Strategies for chromium bioremediation of tannery effluent

Reviews of Environmental Contamination and Toxicology

Volumn 217, Issue , 2012, Pages 75-140

  Garg, Satyendra Kumar ^a   Tripathi, Manikant ^a   Srinath, Thiruneelakantan ^b  

^a DR RAM MANOHAR LOHIA AVADH UNIVERSITY   (India)

^b INDIAN INSTITUTE OF SCIENCE   (India)

Author keywords

[No Author keywords available]

Indexed keywords

CHROMIUM;

BIOREMEDIATION; CHEMISTRY; INDUSTRIAL WASTE; LEATHER INDUSTRY; METABOLISM; POLLUTANT; REVIEW; SEWAGE;

BIODEGRADATION, ENVIRONMENTAL; CHROMIUM; ENVIRONMENTAL POLLUTANTS; INDUSTRIAL WASTE; TANNING; WASTE DISPOSAL, FLUID;

EID: 84858164831     PISSN: 01795953     EISSN: None     Source Type: Book Series    
DOI: 10.1007/978-1-4614-2329-4_2     Document Type: Review

References (385)

1. Abbasi SA, Soni R (1984) Teratogenic effects of chromium (VI) in the environment as evidenced by the impact of larvae of amphibian Rana tigrina : Implications in the environment management of chromium. Int J Environ Stud 23:131-137
2. Ackerley DF, Gonzalez CF, Keyhan M, Blake R, Matin A (2004) Mechanism of chromate reduction by the Escherichia coli protein, NfsA, and the role of different chromate reductases in minimizing oxidative stress during chromate reduction. Environ Microbiol 6:851-860
3. Agarwal SK (1996) Industrial environment-Assessment and strategy. APHA Publishing Company, New Delhi
4. Ahalya N, Ramchandra TV, Kanamadi RD (2003) Biosorption of heavy metals. Res J Chem Environ 7(4):1-10
5. Ahluwalia SS, Goyal D (2007) Microbial and plant derived biomass for removal of heavy metals from waste water. Biores Technol 98:2243-2257
6. Ahn D-H, Chung Y-C, Pak D (1998) Biosorption of heavy metal ions by immobilized Zoogloea and zooglan. Appl Biochem Biotechnol 73:43-50
7. Aksu Z (2005) Application of biosorption for the removal of organic pollutants: A review. Process Biochem 40:997-1026
8. Aksu Z, Acikel U (1999) A single-staged bioseparation process for simultaneous removal of copper (II) and chromium (VI) by using C. vulgaris Process Biochem 34:589-599
9. Aksu Z, Akpinar D (2001) Competitive biosorption of phenol and chromium (VI) from binary mixtures onto dried anaerobic sludge. Biochem Eng J 7:183-193
10. Aksu Z, Egretli G, Kustal T (1999) A comparative study for the biosorption characteristics of chromium (VI) on Ca-Alginate, agarose and immobilized C. vulgaris in a continuous packed bed column. J Environ Sci Health A 34:295-316
11. Aksu Z, Gonen F (2004) Biosorption of phenol by immobilized activated sludge in a continuous packed bed: Prediction of breakthrough curves. Process Biochem 39:599-613
12. Aksu Z, Gonen F (2006) Binary biosorption of phenol and Cr (VI) onto immobilized activated sludge in a packed bed: Prediction of kinetic parameters and breakthrough curves. Sep Purif Technol 49:205-216
13. Akthar MN, Mohan PM (1995) Bioremediation of toxic metal ions from polluted lake waters and industrial effluents by fungal biosorbent. Curr Sci 69:1028-1030
14. Akthar MN, Sastry KS, Mohan PM (1995) Biosorption of silver ions by processed Aspergillus niger biomass. Biotechnol Lett 17:551-556
15. Al-Asheh S, Duvnjak Z (1995) Adsorption of copper and chromium by Aspergillus carbonarius Biotechnol Prog 11:638-642
16. Amudeswari A, Sarvanan J, Rao R, Ramasami T (2009) Leather bioprocessing: A greener finish. Biotechnol News 4(1):4-8, 22
17. Anderson RA (1998) Effects of chromium on body composition and weight loss. Nat Rev 56(9):266-270
18. Andres Y, Thouand G, Boualam M, Mergeay M (2000) Factors influencing the biosorption of gadolinium by micro-organisms and its mobilization from sand. Appl Microbiol Biotechnol 54:262-267
19. Anttila S (1990) Biological effects of occupational and environmental exposure to chromium. In: Coolery P, Poirier LA, Manfait M, Etienne JC (eds) Metal ions in biology and medicine. John Libbey Eurotext, Paris, pp 315-319
20. Antuner APM, Watlins GM, Duncan JR (2001) Batch studies on the removal of gold (III) from aqueous solution by Azolla filiculoides Biotechnol Lett 23:249-151
21. Appanna VD, Gazso LG, Huang J, St Pierre M (1996) Mechanism of chromium detoxification in Pseudomonas fluorescens is dependent on iron. Bull Environ Contam Toxicol 57:875-880
22. Appenroth D, Kersten L (1990) The activity of chromate reduction in renal tissue corresponds nephrotoxicity-developmental aspects. Toxicol Lett 53:157-159
23. Aravindhan R, Balaraman M, Jonnalagadda RR, Balachandran UN, Thirumalachari R (2004) Bioaccumulation of chromium from tannery wastewater: An approach for chromium recovery and reuse. Environ Sci Technol 38(1):300-306
24. Aravindhan R, Sreeram KJ, Rao JR, Nair BU (2007) Biological removal of carcinogenic chromium (VI) using mixed Pseudomonas strains. J Gen Appl Microbiol 53:71-79
25. Arica MY, Bayramoglu G (2005) Cr (IV) biosorption from aqueous solution using free and immobilized biomass of Lentinus sajor-caju : Preparation and kinetic characterization. Colloids Surf A: Physicochem Eng Aspects 253:203-211
26. Asatiani NV, Abuladze MK, Kartvelishvili TM, Bakradze NG, Sapojnikova NA, Tsibakhashvili NY, Tabatadze LV, Lejava LV, Asanishvili LL, Holman H (2004) Effect of Cr (VI) action on Arthrobacter oxydans Curr Microbiol 49:321-326
27. Avudainayagam S, Meghara A, Owens G, Kookana RS, Chittleborough D, Naidu R (2003) Chemistry of chromium in soils with emphasis, on tannery waste sites. Rev Environ Contam Toxicol 178:53-91
28. Bae WC, Kang TG, Kang IK, Won YG, Jeong BC (2000) Reduction of hexavalent chromium by Escherichia coli ATCC 33456 in batch and continuous cultures. J Microbiol 38(1):36-39
29. Bae WC, Lee HK, Choe YC, Jahng DK, Lee SH, Kim SJ, Lee JH, Jeong BC (2005) Purification nd characterization of NADPH-dependent Cr (VI) reductase from Escherichia coli ATCC 33456. J Microbiol 43:21-27
30. Bahijri SMA, Mufti AMB (2002) Beneficial effects of chromium in people with type 2 diabetes, and urinary chromium response to glucose load as a possible indicator of status. Biol Trace Elem Res 85:97-110
31. Bailar JC (1997) Chromium. In: Parker SP (ed) McGraw-Hill encyclopedia of science and technology. McGraw-Hill, New York
32. Baillet F, Margnin J-P, Cheruy A, Ozil P (1998) Chromium precipitation by the acidophilic bacterium Thiobacillus ferrooxidans Biotechnol Lett 20:95-99
33. Barman SC, Sahu RK, Bhargava SK, Chaterjee C (2000) Distribution of heavy metals in wheat, mustard, and weed grown in field irrigated with industrial effluents. Bull Environ Contam Toxicol 64:489-496
34. Barrera LM, Jimenez FMG, Moreno AO, Urbina EC (2008) Isolation, identification and characterization of a Hypocrea tawa strain with high Cr (VI) reduction potential. Biochem Eng J 40:284-292
35. Belay AA (2010) Impact of chromium from tannery effluent and evaluation of alternative treatment options. J Environ Prot 1:53-58
36. Belliveau BH, Starodub ME, Cotter C, Trevors JT (1987) Metal resistance and accumulation in bacteria. Biotechnol Adv 5:101-127
37. Benazir JF, Suganthi R, Rajvel D, Pooja MP, Mathithumilan B (2010) Bioremediation of chromium in tannery effluent by microbial consortia. Afr J Biotechnol 9(21):3140-3143
38. Bender J, Lee RF, Phillips P (1995) Uptake and transformation of metals and metalloids by microbial mats and their use in bioremediation. J Ind Microbiol 14:113-118
39. Beveridge TJ (1978) The response of cell walls of Bacillus subtilis to metals and to electron microscopic strains. Can J Microbiol 24:89-104
40. Beveridge TJ (1988) The bacterial surface: General considerations toward design and function. Can J Microbiol 34:363-372
41. Beveridge TJ, Graham LL (1991) Surface layers of bacteria. Microbiol Rev 55:684-705
42. Bhide JV, Dhakephalkar PK, Paknikar KM (1996) Microbiological process for the removal of Cr (VI) from chromate-bearing cooling tower effluent. Biotechnol Lett 18:667-672
43. Bopp LH, Ehrlich HL (1988) Chromate resistance and reduction in Pseudomonas fluorescens strain LB300. Arch Microbiol 150:426-431
44. Brierley JA, Goyak GM, Brierley CL (1986) Considerations for commercial use of natural products for metal recovery. In: Eccles H, Hunt S (eds) Immobilization of ions by biosorption. Horwood, Chichester, pp 105-117
45. Buljan J, Sahasranaman A (1999) Pollution containment in the tanning industry in developing countries. Proceedings of XXV IULTCS Congress. Tata McGraw-Hill Publishers, New Delhi, pp 410-422
46. Calder LM (1988) Chromium contamination of groundwater. In: Nriagu JO, Neiboer E (eds) Chromium in the natural and human environments. Wiley, New York, pp 215-230
47. Camargo FAO, Okeke BC, Bento FM, Frankenberger WT (2003) In vitro reduction of hexavalent chromium by a cell-free extract of Bacillus sp. ES 29 stimulated by Cu 2+ Appl Microbiol Biotechnol 62:569-573
48. Camargo FAO, Okeke BC, Bento FM, Frankenberger WT (2004) Hexavalent chromium reduction by immobilized cells and the cell-free extract of Bacillus sp. ES 29. Biorem J 8(1-2):23-30
49. Camargo FAO, Okeke BC, Bento FM, Frankenberger WT (2005) Diversity of chromium-resistant bacteia isolated from soils contaminated with dichromate. Appl Soil Ecol 29:193-202
50. Campos J, Martinez-Pacheco M, Cervantes C (1995) Hexavalent-chromium reduction by a chromate resistant Bacillus sp. strain. Antonie Van Leeuwenhoek 68:203-208
51. Campos VL, Moraga R, Yanez J, Zaror CA, Mondaca MA (2005) Chromate reduction by Serratia marcescens isolated from tannery effluent. Bull Environ Contam Toxicol 75:400-406
52. Canter LW (1986) Grounwater pollution control. Lewis Publishers Incorporation, Chelsea Celma PJ, Cerrio R, Choque R,
53. Chelsea Celma PJ, Cerrio R, Choque R, Cabeza LF, Cot J (1999) Chrome recovery from sheepskins tanning baths by an ion exchange (anionic) process. Proceedings of the XXV IULTCS Congress. Pilot scale trials and in tannery chrome reuse. Tata McGraw-Hill Publishers, New Delhi, pp 458-461
54. Cervantes C, Campos-Garica J, Gutierrez-Corona F, Loza-Tavera H, Torres-Guzman JC, Moreno- Sanchez R (2001) Interactions of chromium with microorganisms and plants. FEMS Microbiol Rev 25:335-347
55. Cha J-S, Cooksey DA (1991) Copper resistance in Pseudomonas syringae mediated by periplasmic and outer memebrane proteins. Proc Natl Acad Sci U S A 88:8915-8919
56. Chai L, Huang S, Yang Z, Peng B, Huang Y, Chen Y (2009) Cr (VI) remediation by indigenous bacteria in soils, contaminated by chromium-containing slag. J Hazard Mater 167:516-522
57. Chemical Weekly (2001) Leather units not using treatment plants fully. February 27, 74
58. Chen JM, Hao OJ (1996) Environmental factors and modeling in microbial chromium (VI) reduction. Water Environ Res 68:1156-1164
59. Chen YX, Liu H, Chen HI (2003) Characterization of phenol biodegradation by Coman anastestosteroni ZD4-1 and Pseudomonas aeruginosa ZD4-3. Biomed Environ Sci 16:163-172
60. Cheung KH, Lai HY, Gu JD (2006) Membrane-Associated hexavalent chromium reductase of Bacillus megaterium TKW3 with induced expression. J Microbiol Biotechnol 16:855-862
61. Chirwa EMN, Smit HER (2010) Simultaneous Cr (VI) reduction and phenol degradation in a trickle bed bioreactor: Shock loading response. Chem Eng Trans 20:55-60
62. Chirwa EMN, Wang YT (2000) Simultaneous chromium (VI) reduction and phenol degradation in an anaerobic consortium of bacteria. Water Res 33:2376-2384
63. Chirwa EMN, Wang YT (2001) Simultaneous chromium (VI) reduction and phenol degradation in a fixed-film coculture bioreactor: reactor performance. Water Res 35(8):1921-1932
64. Chirwa EMN, Wang YT (2005) Modeling hexavalent chromium reduction and phenol degradation in a coculture biofilm reactor. ASCE J Environ Eng 131(11):1495-1506
65. Choi SH, Moon S-H, Gu MB (2002) Biodegradation of chlorophenols using the cell-free culture broth of Phanerochaete chrysosporium immobilized in polyurethane foam. J Chem Technol Biotechnol 77:999-1004
66. Cifuentes FR, Lindemann WC, Barton LL (1996) Chromium sorption and reduction in soil with implications to bioremediation. Soil Sci 161:233-241
67. Clark DP (1994) Chromate reductase activity of Enterobacter aerogenes is induced by nitrite. FEMS Microbiol Lett 122:233-238
68. Collins YE, Stotzky G (1992) Heavy metals alter the electrokinetic properties of bacteria, yeasts and clay minerals. Appl Environ Microbiol 58:1592-1600
69. Comte S, Guibaud G, Baudu M (2006) Biosorption properties of extracellular polymeric substances (EPS) resulting from activated sludge according to their type: Soluble or bound. Process Biochem 41:815-823
70. Congeevaram S, Dhanarani S, Park J, Dexilin M, Thamaraiselvi K (2007) Biosorption of chromium and nickel by heavy metal resistant fungal and bacterial isolates. J Hazard Mater 146: 270-277
71. Cooke VM, Hughes MN, Poole RK (1995) Reduction of chromate by bacteria isolated from the cooling water of an electricity generating station. J Ind Microbiol 14:323-328
72. Copley SD (2000) Evolution of metabolic pathway for degradation of a toxic xenobiotic: The patchwork approach. Trends Biochem Sci 25:261-265
73. Costa M (2003) Potential hazards of hexavalent chromium in our drinking water. Toxicol Appl Pharmacol 188:1-5
74. Costerton JW, Lewandowski Z, DeBeer D, Cadwell DE, Korber DE, James GA (1994) Biofilms: The customized microniche. J Bacteriol 176:2137-2142
75. Cotta JG (1921) Buchhandling, 1858 (English translation). J Am Leather Chem Assoc 16:658
76. Das AP, Mishra S (2010) Biodegradation of the metallic carcinogen hexavalent chromium Cr (VI) by an indigenously isolated bacterial strain. J Carcinogen 9:6
77. de Flora S, Bangnasco M, Serra D, Zanacchi P (1990) Genotoxicity of chromium compounds: A review. Mutat Res 238:99-172
78. de Flora S, Wetterhahn KE (1989) Mechanisms of chromium metabolism and genotoxicity. Life Chem Rep 7:169-244
79. Denizil A, Cihangir N, Rad AY, Taner M, Alsancak G (2004) Removal of chlorophenols from synthetic solutions using Phanerochaete chrysosporium Process Biochem 39:2025-2030
80. Desai C, Jain K, Madamwar D (2008a) a) Evaluation of in vitro Cr (VI) reduction potential in cytosolic extracts of three indigenous Bacillus sp. isolated from Cr (VI) polluted industrial landfill. Biores Technol 99:6059-6069
81. Desai C, Jain K, Madamwar D (2008b) b) Hexavalent chromate reductase activity in cytosolic fractions of Pseudomonas sp. G1DM21 isolated from Cr (VI) contaminated industrial landfill. Process Biochem 43:713-721
82. Desjardin V, Bayard R, Lejeune P, Gourdon R (2003) Utilisation of supernatants of pure cultures of Streptomyces thermocarboxydus NH50 to reduce chromium toxicity and mobility in contaminated soils. Water Air Soil Pollut 3:153-160
83. Dey S, Paul AK (2010) Occurrence and evaluation of chromium reducing bacteria in seepage water from chromite mine quarries of Orissa, India. J Water Resour Prot 2(4):380-388
84. Dhal B, Thatoi H, Das N, Pandey BD (2010) Reduction of hexavalent chromium by Bacillus sp. isolated from chromite mine soils and characterization of reduced product. J Chem Technol Biotechnol 85(11):1471-1479
85. Donocik A, Ledin M, Pedersen K, Allard B (1996) Accumulation of zinc and cadmium by Cytophaga johnsonae Biometals 9:169-175
86. Edgehill RU (1996) Degradation of pentachlorophenol (PCP) by Arthrobacter strain ATCC 33790 in biofilm culture. Water Res 30:357-363
87. Edgehill RU, Finn R (1983) Microbial treatment of soil to remove pentachlorophenol. Appl Environ Microbiol 45:1122-1125
88. Elangovan R, Abhipsa S, Rohit B, Ligy P, Chandraraj K (2006) Cr (VI) reduction by a Bacillus sp. Biotechnol Lett 28:247-252
89. Elangovan R, Philip L (2009) Performance of various bioreactors for the removal of Cr (VI) and organic matter from industrial effluent. Biochem Eng J 44:174-186
90. Elizabeth KM, Esther Rani G (2004) Bioremediation of phenol, ammonia, nickel, hexavalent chromium and iron from steel plant effluent of Visakhapatnam city by live, killed and immobilized bacteria. Asian J Chem 16:1269-1273
91. Emsely J (1999) Molecules at exhibition: Portraits of intriguing materials in everyday life. Oxford University Press, Oxford
92. Enterine PE (1974) Respiratory cancer among chromate workers. J Occup Med 16:523-526
93. Ernest M (1991) Metals and their compounds in the environment, occurrence, analysis and biological relevance. VCH, Basel, Weinheim/NY/Cambridge
94. Esmaeili A, Nia AM, Vazirinejad R (2005) Chromium (III) removal and recovery from tannery wastewater by precipitation process. Am J Appl Sci 2(10):1471-1473
95. Failla ML (1977) Zinc: Functions and transport in microorganisms. In: Weinberg ED (ed) Microorganisms and minerals. Marcel Dekker, New York, pp 151-214
96. Faisal M, Hameed A, Hasnain S (2005) Chromium-resistant bacteria and cyanobacteria: Impact on Cr (VI) reduction potential and plant growth. J Ind Microbiol Biotechnol 32:615-621
97. Faisal M, Hasnain S (2004) Microbial conversion of Cr (VI) in to Cr (III) in industrial effluent. Afr J Biotechnol 3(11):610-617
98. Faisal M, Hasnain S (2006) Detoxification of Cr (VI) by Bacillus cereus S-6. Res J Microbiol 1(1):45-50
99. Farag S, Zaki S (2010) Identification of bacterial strains from tannery effluent and reduction of hexavalent chromium. J Environ Biol 31(5):877-882
100. Farrell SO, Ranallo RT (2000) Experiments in biochemistry. A hands-on approach. Saunders College Publisher, Orlando
101. Feng Z, Hu W, Rom WN, Costa M, Tang MS (2004) Chromium (VI) exposure enhances polycyclic aromatic hydrocarbon-DNA binding at the p53 gene in human lung cells. J Carcinogen 24:771-778
102. Findlay A (1934) The spirit of chemistry. Longmans Green and Company, London Flavio AO, Camargo C, Benedict O,
103. Fatima M, Bento W, Frakenberger T (2004) Diversity of chromium-resistant bacteria isolated from soils contaminated with dichromate. Appl Soil Ecol 29:193-202
104. Fourest E, Roux JC (1992) Heavy metal biosorption by fungal mycelial by-products: Mechanisms and influence of pH. Appl Microbiol Biotechnol 37:399-403
105. French C, Peters W, Maxwell B, Rice G, Colli A, Bulf R, Cole J, Heath E, Turner J, Hetes B, Brown DC, Goldin D, Behling H, Loomis D, Behling H, Loomis D, Nelson C (1997) Assessment of health risks due to hazardous air pollutant emissions from electric utilities. Drug Chem Toxicol 20:375-386
106. Fude L, Harris B, Urrutia MM, Beveridge TJ (1994) Reduction of Cr (VI) by a consortium of sulfate-reducing bacteria (SRB-III). Appl Environ Microbiol 60:1525-1531
107. Fude L, Shigui L (1992) Microbial removal and recovery of chromium (VI) from electroplating waste water. J Sichuan Univ (Nat Sci Ed) 2:266-273
108. Gadd GM (1988) Accumulation of metals by microorganisms and algae. In: Rehm HJ, Reed G (eds) Biotechnology: A comprehensive treatise, special microbial process. VCH Verlagsgesellschaft, Weinheim, pp 401-433
109. Gadd GM (1990) Heavy metal accumulation by bacteria and other microorganisms. Experientia 46:834-840
110. Gadd GM, White C (1993) Microbial treatment of metal pollution-A working biotechnology? Trends Biotechnol 11:353-359
111. Ganguli A, Tripathi AK (1999) Survival and chromate reducing ability of Pseudomonas aeruginosa in industrial effluents. Lett Appl Microbiol 28:76-80
112. Ganguli A, Tripathi AK (2002) Bioremediation of toxic chromium from electroplating effluent by chromate-reducing Pseudomonas aeruginosa A2Chr in two bioreactors. Appl Microbiol Biotechnol 58(3):416-420
113. Garbisu C, Alkorta I, Llama MJ, Serra JL (1998) Aerobic chromate reduction by Bacillus subtilis Biodegradation 9:133-141
114. Gasbarro A, Beolchini F, Vegilo F (1997) Biosorption of toxic metals: An equilibrium study using free cells of Arthrobacter sp. Process Biochem 32:99-105
115. Gibb HJ, Lees PS, Pinsky PF, Rooney BC (2000a) Lung cancer among workers in chromium chemical production. Am J Ind Med 38:115-126
116. Gibb HJ, Lees PS, Pinsky PF, Rooney BC (2000b) Clinical findings of irritation among chromium chemical production workers. Am J Ind Med 38:127-131
117. Guan L, Petersen JN, Johnstone DL, Yonge DR, Brouns TM (1993a) Equilibrium sorption of Cr 6+ by a consortia of denitrifying bacteria. Biotechnol Lett 15:727-732
118. Guan L, Petersen JN, Johnstone DL, Yonge DR, Brouns TM (1993b) Sorption rates for the uptake of Cr 6+ by a consortia of denitrifying bacteria. Biotechnol Lett 15:733-736
119. Gulay B, Sema B, Yakup AM (2003) Biosorption of heavy metal ions on immobilized white-rot fungus Trametes versicolor J Hazard Mater B 101:285-300
120. Gupta VK, Rastogi A (2008) Sorption and desorption studies of chromium (VI) from nonviable cyanobacterium Nostoc miscorum biomass. J Hazard Mater B 154:347-354
121. Gvozdyak PI, Mogilevich NF, Ryl'skii AF, Grishchenko NI (1986) Reduction of hexavalent chromium by collection strains of bacteria. Mikrobiologiya 55:962-965
122. Hafez AI, El-Manharawy MS, Khedr MA (2002) RO membrane removal of unreacted chromium from spent tanning effluent. A pilot-scale study, part 2. Desalination 14:237-242
123. Hamed TA, Bayraktar E, Mehmetoglu U, Mehmetoglu T (2004) The biodegradation of benzene, toluene and phenol in a two-phase system. Biochem Eng J 19:137-146
124. He M, Li X, Guo L, Miller SJ, Rensing C, Wang G (2010) Characterization and genomic analysis of chromate resistant and reducing Bacillus cereus strain SJ1. BMC Microbiol 10(1):221
125. Holmes AL, Wise SS, Wise JP Sr (2008) Carcinogenicity of hexavalent chromium. Indian J Med Res 128:353-372
126. Horitsu H, Futo S, Miyazawa Y, Ogai S, Kawai K (1987) Enzymatic reduction of hexavalent chromium by hexavalent chromium tolerant Pseudomonas ambigua G-1. J Agric Biol Chem 51:2417-2420
127. Horitsu H, Futo S, Ozawa K, Kawai K (1983) Comparison of characteristics of hexavalent chromium-Tolerant bacterium, Pseudomonas ambigua G-1, and its hexavalent chromium-sensitive mutant. J Agric Biol Chem 47:2907-2908
128. Horsfall M Jr, Ogban F, Akporhonor EE (2006) Sorption of chromium (VI) from aqueous solution by cassava ( Manihot sculenta CRANZ) waste biomass. J Chem Biodiver 3:161-173
129. Hu MZ-C, Reeves M (1997) Biosorption of uranium by Pseudomonas aeruginosa strain CSUimmobilized in a novel matrix. Biotechnol Prog 13:60-70
130. Huang CP, Wu MH (1977) The removal of chromium (VI) from dilute aqueous solution by activated carbon. Water Res 11:673-679
131. Huges MN, Poole RK (1989) Metals and microorganisms. Chapman and Hall, London Humphries AC, Nott KP, Hall LD,
132. Macaskie LE (2005) Reduction of Cr (VI) by immobilized cells of Desulfovibrio vulgaris NCIMB 8303 and Microbacterium sp. NCIMB 13776. Biotechnol Bioeng 90(5):589-596
133. Ilias M, Rafiqullah IM, Debnath BC, Mannan KSB, Hoq MM (2011) Isolation and characterization of chromium (VI)-reducing bacteria from tannery effluents. Indian J Microbiol 51(1):76-81
134. Ishibashi Y, Cervantes C, Silver S (1990) Chromium reduction in Pseudomonas putida Appl Environ Microbiol 56:2268-2270
135. Ito M, Ohnishi Y (1982) Escherichia coli mutants which are resistant to uncouplers of oxidative phosphorylation. J Microbiol Immunol 26(11):1079-1084
136. Iyer A, Mody K, Jha B (2004) Accumulation of hexavalent chromium by an exopolysaccharide producing marine Enterobacter cloaceae Mar Pollut Bull 49:974-977
137. James BR, Barlett RJ (1983) Behavior of chromium in soils. VII. Adsorption and reduction of hexavalent forms. J Environ Qual 12(2):177-181
138. Janus JA, Krajnc EI (1990) Integrated criteria document chromium: Effects - Appendix, National Institute of Public Health and Environmental Protection, Report No. 710401002. Bilthoven, The Netherlands, p 89
139. Jeyasingh J, Philip L (2005) Bioremediation of chromium contaminated soils: Optimization of operating parameters under laboratory conditions. J Hazard Mat B 118:113-120
140. Kapoor A, Viraraghavan T (1995) Fungal biosorption-An alternative treatment option of heavy metal bearing wastewater: A review. Biores Technol 53:195-206
141. Kar NS, Dasgupta AK (1996) The possible role of surface charge in membrane organization in an acidophile. Indian J Biochem Biophys 33:398-402
142. Katz SA, Salem H (1994) The biological and environmental chemistry of chromium. VCH Publishers Incorporation, New York
143. Kazy SK, Sar P, Asthana RK, Singh SP (1999) Copper uptake and its compartmentalization in Pseudomonas aeruginosa strains: Chemical nature of cellular metal. World J Microbiol Biotechnol 15:599-605
144. Keely JF, Boateng K (1987) Monitoring well installation, purging, and sampling techniques-part 2: Case histories. Ground Water 25:427-439
145. Kilic NK, Donmez G (2008) Environmental conditions affecting exopolysaccharide production by Pseudomonas aeruginosa , Micrococcus sp., and Ochrobactrum sp. J Hazard Mater 154:1019-1024
146. Kimbrough DE, Cohen Y, Winer AM, Creeman L, Mabuni C (1999) A critical assessment of chromium in the environment. CRC Crit Rev Environ Sci Technol 29:1-46
147. Komori K, Rivas A, Toda K, Ohtake H (1990) Biological removal of toxic chromium using an Enterobacter cloacae strain that reduces chromate under anaerobic conditions. Biotechnol Bioeng 35:951-954
148. Komori K, Wang PC, Toda K, Ohtake H (1989) Factors affecting chromate reduction in Enterobacter cloacae strain HO1. Appl Microbiol Biotechnol 31:567-570
149. Kong S, Yonge DR, Johnstone DL, Petersen JN, Brouns TM (1992) Chromium distribution in subcellular components between fresh and subsurface bacterial consortium. Biotechnol Lett 14:521-524
150. Kong S, Yonge DR, Johnstone DL, Petersen JN, Brouns TM (1993) Competing ion effect on chromium adsorption with fresh and starved subsurface bacterial consortium. Biotechnol Lett 15:87-92
151. Kotas J, Stasicka Z (2000) Chromium occurrence in the environment and methods of its speciation. Environ Pollut 107:263-283
152. Kratochvil D, Pimentel P, Volesky B (1998) Removal of trivalent and hexavalent chromium by seaweed biosorption. Environ Sci Technol 32:2693-2698
153. Kratochvil D, Volesky B (1998) Advances in the biosorption of heavy metals. Trends Biotechnol 16:291-300
154. Kulczycki E, Ferris FG, Fortin D (2002) Impact of cell wall structure on the behaviour of bacterial cells as sorbents of cadmium & lead. Geomicrobiol J 19:553-565
155. Kumar SPA, Mahimairaja S, Ramasamy K, Naidu R (1999) Impact of treated effluent on flower crops, soil and on water quality. Proceedings of the second international conference on contaminants in the soil environment in the Australasia-Pacific region. INSCR, New Delhi, India, pp 351-352
156. Kurek E, Czaban J, Bollag J-M (1982) Sorption of cadmium by microorganisms in competition with other soil constituents. Appl Environ Microbiol 43:1011-1015
157. Kuyucak N, Volesky B (1988) Biosorbents for recovery of metals from industrial solutions. Biotechnol Lett 10(2):137-142
158. Kwon SI, Jung KY, Kim KH (1999) Effect of long-Term application of some organic wastes on the distribution and availability of heavy metals in the soil-plant system. Proceedings of the second international conference on contaminants in the soil environment in the Australasia-Pacific region. INSCR, New Delhi, India, pp 254-255
159. Langard S (1990) One hundred years of chromium and cancer: A review of epidemiological evidence and selected case reports. Am J Ind Med 17:189-215
160. Lange CC, Wackett LP, Minton KW, Daly MJ (1998) Engineering Deinococcus radiodurans for organopollutant degradation in radioactive mixed waste environments. Nat Biotechnol 16:929-933
161. Langley S, Beveridge TJ (1999) Effect of O-side chain-lipopolysaccharide chemistry on metal binding. Appl Environ Microbiol 65:489-498
162. Lebedeva EV, Lyalikova NN (1979) Reduction of crocoite by Pseudomonas chromatophila sp. nov. Microbiologiya 48:517-522
163. Leduc G, Pierce RC, McCracken IR (1982) The effects of cyanides on aquatic organisms with emphasis upon freshwater fishes. National Research Council Canada, NRCC No. 19246, p 139
164. Lee SE, Lee JU, Chon HT, Lee JS (2008) Microbiological reduction of hexavalent chromium by indigenous chromium-resistant bacteria in sand column experiments. Environ Geochem Health 30:141-145
165. Levis AG, Bianchi V (1982) Mutagenic and cytogenic effects of chromium compounds. In: Langard S (ed) Biological and environmental aspects of chromium. Elesvier, Amsterdam, pp 171-208
166. Lima SAC, Raposo MFJ, Castro PML, Morais RM (2004) Biodegradation of p -chlorophenol by a microalgae consortium. Water Res 38:97-102
167. Liu N, Luo S, Yang Y, Zhang T, Jin J, Liao J (2002) Biosorption of americium-241 by Saccharomyces cerevisiae J Radioanal Nucl Chem 252:187-191
168. Liu YG, Pan C, Xia WB, Zeng GM, Zhou M, Liu YY, Ke J, Huang C (2008) Simultaneous removal of Cr (VI) and phenol in consortium culture of Bacillus anthracis and Pseudomonas putida Migula (CCTCC AB92019). Trans Nonf Met Soc China 18:1014-1020
169. Liu YG, Xu WH, Zeng GM, Li X, Gao H (2006) Cr (VI) reduction by Bacillus sp. isolated from chromium landfill. Process Biochem 41:1981-1986
170. Liu YG, Xu WH, Zeng GM, Tang CF, Li CF (2004) Experimental study on reduction by Pseudomonas aeruginosa J Environ Sci 16(5):797-801
171. Lock K, Janssen CR (2002) Ecotoxicology of chromium (III) to Eisenia fetida, Enchytraeus albidus and Folsomia candida Ecotoxicol Environ Saf 51:203-205
172. Lokeshwari N, Joshi K (2009) Biosorption of heavy metal (chromium) using biomass. Global J Environ Res 3(1):29-35
173. Losi ME, Amrhein C, Frankenberger WT (1994a) Environmental biochemistry of chromium. Rev Environ Contam Toxicol 36:91-121
174. Losi ME, Amrhein C, Frankenberger WT (1994b) Bioremediation of chromate-contaminated groundwater by reduction and precipitation in surface soils. J Environ Qual 23:1141-1150
175. Love AHG (1983) Chromium- biological and analytical considerations. In: Burrows D (ed) Chromium: Metabolism and toxicity. CRC, Boca Raton, pp 1-12
176. Lovely DR (1995) Bioremediation of organic and metal contaminants with dissimilatory metal reduction. J Ind Microbiol 14:85-93
177. Lovely DR, Coates JD (1997) Bioremediation of metal contamination. Curr Opin Biotechnol 8:285-289
178. Lovely DR, Phillips EJP (1994) Reduction of chromate by Desulfovibrio vulgaris and its c 3 cytochrome. Appl Environ Microbiol 60:726-728
179. Lovera S, Bonet R, Simon-Pujal MD, Congregado F (1993) Chromate reduction by resting cells of Agrobacterium radiobacter EPS-916. Appl Environ Microbiol 59:3516-3518
180. Lu YL, Yang JL (1995) Long-Term exposure to chromium (VI) oxide leads to defects in sulfates in sulfate transport system in Chinese hamster ovary cells. J Cell Biochem 57:655-665
181. Luo H, Lu Y, Mao Y, Shi X, Dalal NS (1996) Role of chromium (IV) in the chromium (VI)-related free radical formation, dG hydroxylation, and DNA damage. J Inorg Biochem 64:25-35
182. Mabbett AN, Macaskie LE (2001) A novel isolate of Desulfovibrio sp. with enhanced ability to reduce Cr (VI). Biotechnol Lett 23:683-687
183. Mala JGS, Nair BU, Puvanakrishnan R (2006) Bioaccumulation and biosorption of chromium by Aspergillus niger MTCC 2594. J Gen Appl Microbiol 52:179-186
184. Mance G (1987) Pollution threat of heavy metals in aquatic environments. Elesevier Applied Science, New York, pp 31-60, 134-135
185. Maria MV, Bertha AR, Carlos GSJ (1999) Health deterioration by chromium in workers of a tannery unit. Proceedings of the XXV IULTCS Congress. Tata McGraw-Hill Publishers, New Delhi, pp 725-730
186. Marques AM, Roca X, Simon-Pujol MD, Fuste MC, Congregado F (1991) Uranium accumulation by Pseudomonas sp. EPS-5028. Appl Microbiol Biotechnol 35:406-410
187. Masood F, Malik A (2011) Hexavalent chromium reduction by Bacillus sp. Strain FM1 isolated from heavy-metal contaminated soil. Bull Environ Contam Toxicol 86:114-119
188. Mathew A, Thanga V, Salom G, Reshma JK (2010) Simultaneous phenol degradation and chromium (VI) reduction by bacterial isolates. Res J Biotechnol 5(1):46-49
189. McLaughlin GD, Theis ER (1945) The chemistry of leather manufacture, vol 101, American Chemical Society in monograph. Reinhold Publishing Corporation, New York
190. McLean J, Beveridge TJ (2001) Chromate reduction by a Pseudomonad isolated from a site contaminated with chromated copper arsenate. Appl Environ Microbiol 67:1076-1084
191. McLean J, Beveridge TJ, Phipps D (2000) Isolation and characterization of a chromium-reducing bacterium from a chromated carbon arsenate-contaminated site. Environ Microbiol 2:611-619
192. Megharaj M, Avudainayagam S, Naidu R (2003) Toxicity of hexavalent chromium and its reduction by bacteria isolated from soil contaminated with tannery waste. Curr Microbiol 47:51-54
193. Mejare M, Bulow L (2001) Metal-binding proteins and peptides in bioremediation and phytoremediation of heavy metals. Trends Biotechnol 19:67-73
194. Merrin JS, Sheela R, Saswathi N, Prakasham RS, Ramakrishna SV (1998) Biosorption of chromium VI using Rhizopus arrhizus Indian J Exp Biol 36:1052-1055
195. Mertz W (1974) Chromium as a dietary essential for man. In: Hockstra WG, Suttie JW, Ganther KE, Mertz W (eds) Trace elements metabolism. University Park Press, Baltimore, pp 185-198
196. Mertz W (1998) Chromium research from a distance: From 1959 to 1980. J Am Coll Nutr 17: 544-547
197. Michel C, Brugna M, Aubert C, Bernadac A, Bruschi M (2001) Enzymatic reduction of chromate: Comparative studies using sulfate-reducing bacteria. Appl Microbiol Biotechnol 55:95-100
198. Mishra S, Doble M (2008) Novel chromium tolerant microorganisms: Isolation, characterization and their biosorption capacity. Ecotoxicol Environ Saf 71:874-879
199. Moore JW, Ramamoorthy S (2001) IUE assessment for chromium containing waste from the leather industry. http://www.ctc.fr/faq/docs/CTC-recommendations
200. Morris BW, Griffiths H, Kemp J (1988) Effect of glucose loading on concentration of chromium in plasma and urine of healthy adults. Clin Chem 34:1114-1116
201. Mukherjee AB (1998) Chromium in the environment of Finland. Sci Total Environ 217:9-19
202. Murugesan AG, Maheswari S (2007) Uptake of hexavalent chromium from aqueous solution employing live, dead and immobilized bacterial biomass. J Appl Sci Environ Manage 11(4):71-75
203. Myers CR, Carstens BP, Antholine WE, Myers JM (2000) Chromium (VI) reductase activity is associated with the cytoplasmic membrane of anaerobically grown Shewanella putrifaciens MR-1. J Appl Microbiol 88:98-106
204. NAS (1974) The relation of selected trace elements to health and disease. In: Geochemistry and the Environment-I. US National Academy of Engineering, Washington, DC, p 533
205. Nath K, Singh D, Shyam S, Sharma YK (2009) Phytotoxic effects of chromium and tannery effluent on growth and metabolism of Phaseolus mungo Roxb. J Environ Biol 30:227-234
206. Nies DH (1999) Microbial heavy-metal resistance. Appl Microbiol Biotechnol 51:730-750
207. Nies DH, Silver S (1989) Plasmid-determined inducible efflux is responsible for resistance to cadmium, zinc, and cobalt in Alcaligenes eutrophus J Bacteriol 171:896-900
208. Nishioka H (1975) Mutagenic activities of metal compounds in bacteria. Mutat Res 31:185-189
209. Niu H, Volesky B (1999) Characteristics of gold biosorption from cyanide solution. J Chem Technol Biotechnol 74:778-784
210. Norseth T (1986) The carcinogenicity of chromium and its salts. Braz J Ind Med 43:649-651
211. Nriagu JO (1988a) Historical perspectives. In: Nriagu JO, Neiboer E (eds) Chromium in the natural and human environments. Wiley, New York, pp 1-20
212. Nriagu JO (1988b) Production and uses of chromium. In: Nriagu JO, Neiboer E (eds) Chromium in the natural and human environments. Wiley, New York, pp 81-104
213. Nriagu JO, Pacyna JM (1989) Quantitative assessment of worldwide contamination of air, water and soils by trace metals. Nature 333:134-139
214. Oboh OI, Aluyor EO (2008) The removal of heavy metal ions from aqueous solutions using sour sop seeds as biosorbent. Afr J Biotechnol 7(24):4508-4511
215. Ohtake H, Cervantes C, Silver S (1987) Decreased chromate uptake in Pseudomonas fluorescens carrying a chromate resistance plasmid. J Bacteriol 169:3853-3856
216. Ohtake H, Fujii E, Toda K (1990a) A survey of effective electron-donors for reduction of toxic hexavalent chromium by Enterobacter cloacae J Gen Appl Microbiol 36:198-206
217. Ohtake H, Fujii E, Toda K (1990b) Reduction of toxic chromate in an industrial effluent by use of a chromate-reducing strain of Enterobacter cloacae Environ Technol 11:663-668
218. Olson PA, Foster RF (1956) Effect of chronic exposure of sodium dichromate on young Chinook salmon and rainbow trout (Annual Report for 1955/56, HW 41500:35). Hanford Biological Research,
219. Richland Omar NB, Merroun ML, Penalver JMA, Munaz TG (1997) Comparative heavy metal biosorption study of brewery yeast and Myxococcus xanthus biomasss. Chemosphere 35:2277-2283
220. Omoike A, Chorover J (2004) Spectroscopic study of extracellular polymeric substances from Bacillus subtilis : Aqueous chemistry and adsorption effects. Biomacromolecules 5:1219-1230
221. One B-L (1988) Genetic approaches in the study of chromium toxicity and resistance in yeast and bacteria. In: Nriagu JO, Neiboer E (eds) Chromium in the natural and human environments. Wiley, New York, pp 351-368
222. Padmesh TVN, Vijayaraghavan K, Sekaran G, Velan M (2005) Batch and column studies on biosorption of acid dyes on fresh water macro alga Azolla filiculoides J Hazard Mater B 125: 121-129
223. Padmesh TVN, Vijayaraghavan K, Sekaran G, Velan M (2005) Batch and column studies on biosorption of acid dyes on fresh water macro alga Azolla filiculoides J Hazard Mater B 125: 121-129
224. Paknikar KM, Puranik PR, Pethkar AV (1999) Development of microbial biosorbents-A need for standardizations of experimental protocols. In: Amils R, Ballester A (eds) Biohydrometallurgy and the environment toward the mining of the 21st century. Part B: Molecular biology, biosorption, bioremediation. Elsevier, Amsterdam, pp 363-373
225. Pal A, Dutta S, Paul AK (2005) Reduction of hexavalent chromium by cell-free extract of Bacillus sphaericus AND 303 isolated from serpentine soil. Curr Microbiol 66:327-330
226. Palmer CD, Puls RW (1994) EPA ground water issue: natural attenuation of hexavalent chromium in groundwater and soils. Washington, DC, Report 540/R-95-512. U.S. Environmental Protection Agency
227. Palmer CD, Wittbrodt PR (1991) Processes affecting the remediation of chromium-contaminated sites. Environ Health Perspect 92:25-40
228. Parameswari E, Lakshmanan A, Thilagavathi T (2009) Biosorption of chromium (VI) and nickel (II) by bacterial isolates from an aqueous solution. Electron J Environ Agric Food Chem 8(3):150-156
229. Park CH, Keyan M, Wielinga B, Fendorf S, Matin A (2000) Purification to homogeneity and characterization of a novel Pseudomonas putida chromate reductase. Appl Environ Microbiol 66(5):1788-1795
230. Park D, Yun Y-S, Park JM (2005) Use of dead fungal biomass for the detoxification of hexavalent chromium: Screening and kinetics. Process Biochem 40:2559-2565
231. Park RM, Bena JM, Stayner LT, Smith RJ, Gibb HJ, Lees PHJ (2004) Hexavalent chromium and lung cancer in the chromate industry: A quantitative risk assessment. Risk Anal 24:1099-1108
232. Parkar MA, Flint SH, Palmer JS, Brooks JD (2001) Factors influencing attachment of thermophilic bacilli to stainless steel. J Appl Microbiol 90:901-908
233. Parvathi K, Nagendran R, Nareshkumar R (2007) Effect of pH on chromium biosorption by chemically treated Saccharomyces cerevisiae J Sci Ind Res 66:675-679
234. Pattanapipitpaisal P, Brown NL, Macaskie LE (2001) Chromate reduction by Microbacterium liquefaciens immobilized in polyvinyl alcohol. Biotechnol Lett 23:61-65
235. Pattanapipitpaisal P, Mabbett AN, Finlay JA, Beswick AJ, Paterson-Beedle M, Essa AM, Wright J, Tolley MR, Badar U, Ahmed N, Hobman JL, Brown NL, Macaskie LE (2002) Reduction of Cr(VI) and bioaccumulation of chromium by Gram-positive and Gram-negative microorganisms not previously exposed to Cr-stress. Environ Technol 23:731-745
236. Patterson JW (1985) Industrial wastewater treatment technology. Butterworth Publishers, Stoneham
237. Paulsen IT, Saier MH Jr (1997) A novel family of ubiquitous heavy metal ion transport proteins. J Membr Biol 156:99-103
238. Pedersen LM, Permin H (1988) Rheumatic disease, heavy-metal pigments, and the great masters. Lancet 331(8597):1267-1269
239. Pethkar AV, Paknikar KM (1998) Recovery of gold from solutions using Cladosporium cladosporiodies biomass beads. J Biotechnol 63:121-136
240. Philip L, Iyengar L, Venkobachar C (1998) Cr (VI) reduction by Bacillus coagulans isolated from contaminated soils. J Environ Eng 124(12):1165-70
241. Polti MA, Amoroso MJ, Abate CM (2010) Chromate reductase activity in Streptomyces sp. MC1. J Gen Appl Microbiol 56:11-18
242. Polti MA, Amoroso MJ, Abate CM (2011) Intracellular chromium accumulation by Streptomyces sp. MC1. Water Air Soil Pollut 214:49-57
243. Polti MA, Gracia RO, Amoroso MJ, Abate CM (2009) Bioremediation of chromium (VI) contaminated soil by Streptomyces sp. MC1. J Basic Microbiol 49(3):285-292
244. Poopal AC, Laxman RS (2008) Hexavalent chromate reduction by immobilized Strepomyces griseus Biotechnol Lett 30:1005-1010
245. Postgate J (1984) The sulfate-reducing bacteria. Cambridge University Press, Cambridge, pp 56-100
246. Prakasham RS, Merrie JS, Sheela R, Saswathi N, Ramakrishna SV (1999) Biosorption of chromium VI by free and immobilized Rhizopus arrhizus Environ Pollut 104:421-427
247. Puranik PR, Paknikar KM (1997) Biosorption of lead and zinc solutions using Streptoverticillium cinnamoneum waste biomass. J Biotechnol 55:113-124
248. Puranik PR, Paknikar KM (1999) Biosorption of lead, cadmium, and zinc by Citrobacter strain MCMB-181: Characterization studies. Biotechnol Prog 15:228-237
249. Quazilbash AA, Faryal R, Naqvi KB, Ahmad S, Hameed A (2006) Efficacy of indigenous Bacillus species in the removal of chromium from industrial effluent. Biotechnology 5:12-20
250. Quintelas C, Fernandes B, Castro J, Figueiredo H, Tavares T (2008) Biosorption of Cr (VI) by three different bacterial species supported on granular activated carbon-A comparative study. J Hazard Mater 153:799-809
251. Quintelas C, Sousa E, Silva F, Neto S, Tavares T (2006) Competitive biosorption of ortho-cresol, phenol, chlorophenol and chromium (VI) from aqueous solution by a bacterial biofilm supported on granular activated carbon. Process Biochem 41:2087-2091
252. Quintelas C, Tavares T (2001) Removal of chromium (VI) and cadmium (II) from aqueous solution by a bacterial biofilm supported on granular activated carbon. Biotechnol Lett 23:1349-1353
253. Quintelas C, Tavares T (2002) Lead (II) and iron (II) removal from aqueous solution: Biosorption by a bacterial biofilm supported on granular activated carbon. J Res Environ Biotechnol 3:196-202
254. Rahman MU, Gul S, Haq MZU (2007) Reduction of chromium (VI) by locally isolated Pseudomonas sp. C-171. Turkish J Biol 31:161-166
255. Rajamani S, Ramasami T, Langerwerf JSA, Schappman JE (1995) Environment management in tanneries, feasible chromium recovery and reuse system. Proceedings of the third international conference on appropriate waste management technologies for developing countries. Nagpur, pp 965-973
256. Rajwade JM, Saluke PB, Paknikar KM (1999) Biochemical basis of chromate reduction by Pseudomonas mendocina In: Amils R, Ballester A (eds) Biohydrometallurgy and the environment toward the mining of the 21st century. Elsevier, Amsterdam, pp 105-114
257. Rama Krishna K, Philip L (2005) Bioremediation of Cr (VI) in contaminated soils. J Hazard Mater B 121:109-117
258. Rao JR, Chandrababu NK, Rao PS, Ramesh R, Suthanthararajan R, Nair BU, Nair KM, Warrier KGK, Rajamani S, Ramasami T, Langerwerf JSA (1999) Surveillance of chromium in tanning: A revisit. Proceedings of the XXV IULTCS Congress. Tata McGraw-Hill Publishers, New Delhi, pp 295-301
259. Ray SA, Ray MK (2009) Bioremediation of heavy metal toxicity-with special reference to chromium. Al Ameen J Med Sci 2(2):57-63
260. Rehman A, Shakoori FR, Shakoori AR (2007) Heavy metal resistant Distigma proteus (Euglenophyta) isolated from industrial effluents and its possible role in bioremediation of contaminated wastewaters. World J Microbiol Biotechnol 23:753-758
261. Rehman A, Zahoor A, Muneer B, Hasnain S (2008) Chromium tolerance and reduction potential of a Bacillus sp.ev3 isolated from metal contaminated wastewater. Bull Environ Contam Toxicol 81:25-29
262. Reid VM, Wyatt KW, Horn JA (1994) A new angle on groundwater remediation. J Civil Eng 64:56-58
263. Reidske JH (1956) Chromium toxicity to plants (Annual Report for 1955/56, HW 41500:48). Hanford Biological Research, Richland
264. Richard EC, Bourg ACM (1991) Aqueous geochemistry of chromium: A review. Water Res 25:807-816
265. Roe FJC, Carter RL (1969) Chromium carcinogenesis: Calcium chromate as a potent carcinogen from the subcutaneous tissues of the rat. Br J Cancer 23:172-176
266. Sag Y, Acikel U, Aksu Z, Kustal T (1998) A comparative study of the simultaneous biosorption of Cr (VI) and Fe (III) on C. vulgaris and R. arrhizus : Application of the competitive adsorption models. Process Biochem 33:273-281
267. Sag Y, Kustal T (1989) The use of Zoogloea ramigera in waste water treatment containing Cr (VI) and Cd (II) ions. Biotechnol Lett 11:145-148
268. Sag Y, Kustal T (1996a) The selective biosorption of chromium (VI) and copper (III) ions from binary metal mixtures by R. arrhizus Process Biochem 31:561-572
269. Sag Y, Kustal T (1996b) Fully competitive biosorption of chromium (VI) and iron (III) ions from binary metal mixtures by R. arrhizus : Use of the competitive Langmuir model. Process Biochem 31:573-585
270. Saifuddin N, Raziah AZ (2007) Removal of heavy metals from industrial effluent using Saccharomyces cerevisiae (Baker's yeast) immobilized in chitosan/lignosulphonate matrix. J Appl Sci Res 3(12):2091-2099
271. Sakthivel S, Civakaran J, Ramasamy K, Naidu R (1999) Impact of tannery effluent irrigation on soil, groundwater and tree growth. Proceedings of the second international conference on contaminants in the soil environment in the Australasia-Pacific region. INSCR, New Delhi, India, pp 355-356
272. Salunkhe PB, Dhakephalkar PK, Paknikar KM (1998) Bioremediation of hexavalent chromium in soil microcosms. Biotechnol Lett 20:749-751
273. Sarkar KT (1991) Theory and practice of leather manufacture. K. T. Sarkar Publisher, India Sarvanan K, Mahimairaja S,
274. Ramasamy K, Naidu R (1999) Is there potential for use of tannery sludge for plant production? Proceedings of the second international conference on contaminants in the soil environment in the Australasia-Pacific region. INSCR, New Delhi, India, pp 349-350
275. Sau GB, Chatterjee S, Mukherjee SK (2010) Chromate reduction by cell-free extract of Bacillus firmus KUCr1. Polish J Microbiol 59(3):185-190
276. Sau GB, Chatterjee S, Sinha S, Mukherjee SK (2008) Isolation and characterization of a Cr (VI) reducing Bacillus firmus from industrial effluents. Polish J Microbiol 57:327-332
277. Sauter S, Buxton KS, Macek KJ, Petrocelli SR (1976) Effects of exposure of heavy metals on selected freshwater fish. Toxicity of copper, cadmium, chromium and lead to eggs and fry of seven fish species (EPA-600/3-76-105). U. S. Environmental Protection Agency, Washington
278. Saxena DK, Murthy RC, Jain VK, Chandra SV (1990) Fetoplacental-maternal uptake of hexavalent chromium administered orally in rats and mice. Bull Environ Contam Toxicol 45:430-435
279. Sepehr MN, Nasseri S, Assadi MM, Yaghmaian K (2005) Chromium bioremoval from tannery industries effluent by Aspergillus oryzae Iranian J Environ Health Sci Eng 2(4):273-279
280. Shah S, Thakur IS (2002) Enrichment and characterization of a microbial community from tannery effluent for degradation of pentachlorophenol. World J Microbiol Biotechnol 18:693-698
281. Shakoori AR, Makhdoom M, Haq RU (2000) Hexavalent chromium reduction by a dichromateresistant gram-positive bacterium isolated from effluents of tanneries. Appl Microbiol Biotechnol 53:348-351
282. Sharma A, Thakur IS (2008) Characterization of pentachlorophenol degrading bacterial consortium from chemostat. Bull Environ Contam Toxicol 81:12-18
283. Sharma DC, Chatterjee C, Sharma CP (1995) Chromium accumulation and its effects on wheat ( Triticum aestivum L. cv. HD 2204) metabolism. Plant Sci 111:145-151
284. Sharma DC, Forster CF (1993) Removal of hexavalent chromium using Sphagnum moss peat. Water Res 27:1201-1208
285. Sharma DC, Forster CF (1994a) A preliminary examination into the adsorption of hexavalent chromium using low-cost adsorbents. Biores Technol 47:257-264
286. Sharma DC, Forster CF (1994b) The treatment of chromium wastewaters using the sorptive potential of leaf mould. Biores Technol 49:31-40
287. Shen H, Wang YT (1993) Characterization of enzymatic reduction of hexavalent chromium by Escherichia coli ATCC 33456. Appl Environ Microbiol 59:3771-3777
288. Shen H, Wang YT (1994a) Modeling hexavalent chromium reduction in Escherichia coli ATCC 33456. Biotechnol Bioeng 43(4):293-300
289. Shen H, Wang YT (1994b) Biological reduction of chromium by E. coli J Environ Eng 120:560-572
290. Shen H, Wang YT (1995) Modeling simultaneous hexavalent chromium reduction and phenol degradation by a defined coculture of bacteria. Biotechnol Bioeng 48:606-616
291. Shi X, Dalal NS (1990) On the hydroxyl radical formation in the reaction between hydrogen peroxide and biologically generated chromium (V) species. Arch Biochem Biophys 277:342-350
292. Shi X, Ding M, Ye J, Wang S, Leonard SS, Zang L, Castranova V, Vallyathan V, Chiu A, Dalal N, Liu K (1999) Cr (VI) causes activation of nuclear transcription factor-Kb, DNA strand breaks and Dg hydroxylation via free radical reactions. J Inorg Biochem 75:37-44
293. Shukla OP, Rai UN, Dubey S (2009) Involvement and interaction of microbial communities in the transformation and stabilization of chromium during the composting of tannery effluent treated biomass of Vallisneria spiralis L. Biores Technol 100:2198-2203
294. Shumate SE, Strandberg GW (1985) Accumulation of metals by microbial cells. In: Moo-Young M, Robinson CW, Howell JA (eds) Comprehensive biotechnology. Pergamon, New York, pp 235-247
295. Siegel S, Keller P, Galun M, Lehr H, Siegel B, Galun B (1986) Biosorption of lead and chromium by Penicillium preparations. Water Air Soil Pollut 27:69-75
296. Silva B, Figueiredo H, Neves IC, Tavares T (2009) The role of pH on Cr (VI) reduction and removal by Arthrobacter viscosus Int J Chem Biomol Eng 2:100-103
297. Silver S, Walderhaug M (1992) Gene regulation of plasmid-And chromosome-determined inorganic ion transport in bacteria. Microbiol Rev 56:195-228
298. Simmons P, Singleton I (1996) A method to increase silver biosorption by an industrial strain of Saccharomyces cerevisiae Appl Microbiol Biotechnol 45:278-285
299. Singh S, Chandra R, Patel DK, Rai V (2007) Isolation and characterization of novel Serratia marcescens (AY927692) for pentachlorophenol degradation from pulp and paper mill waste. World J Microbiol Biotechnol 23:1747-1754
300. Smillie RH, Hunter K, Loutit M (1981) Reduction of chromium (VI) by bacterially produced hydrogen sulphide in a marine environment. Water Res 15:1351-1354
301. Smith WL, Gadd GM (2000) Reduction and precipitation of chromate by mixed culture sulphatereducing bacterial biofilms. J Appl Microbiol 88:983-991
302. Song H, Liu Y, Xu W, Zeng G, Aibibu N, Xu L, Chen B (2009) Simultaneous Cr (VI) reduction and phenol degradation in pure cultures of Pseudomonas aeruginosa CCTCC AB91095. Biores Technol 100:5079-5084
303. Sreeram KJ, Ramasami T (2003) Sustaining tanning process through conservation, recovery and better utilization of chromium resources. Resour Conserv Recycl 38:185-212
304. Srinath T, Garg SK, Ramteke PW (2002a) Cr (VI) accumulation by Bacillus circulans : Effect of various growth conditions. Indian J Microbiol 42:141-146
305. Srinath T, Garg SK, Ramteke PW (2003a) Biosorption and elution of chromium from immobilized Bacillus coagulans biomass. Indian J Exp Biol 41:986-990
306. Srinath T, Garg SK, Ramteke PW (2003b) Biosorption and elution of Cr (VI): A detoxification strategy. In: Roussos R, Soccol CR, Pandey A, Augus C (eds) New horizons in biotechnology. Kluwer Academic Publishers, Netherlands, pp 251-265
307. Srinath T, Khare S, Ramteke PW (2001) Isolation of hexavalent chromium-reducing Cr-Tolerant facultative anaerobes from tannery effluent. J Gen Appl Microbiol 47:307-312
308. Srinath T, Ramteke PW (1999) Heavy metals contamination in sludge of tannery effluent treatment plants and their toxicity. Proceedings of the second international conference on contaminants in the soil environment in the Australasia-Pacific region. INSCR, New Delhi, India, pp 72-73.
309. Srinath T, Verma T, Ramteke PW, Garg SK (2002b) Chromium (VI) biosorption and bioaccumulation by chromate resistant bacteria. Chemosphere 48:427-435
310. Srivastava A, Pathak AN (1997) Status report on tannery wastes and special reference to tanneries at Kanpur, U.P. J Sci Ind Res 58:453-459
311. Srivastava J, Chandra H, Tripathi K, Naraian R, Sahu RK (2008) Removal of chromium (VI) through biosorption by the Pseudomonas spp. isolated from tannery effluent. J Basic Microbiol 48:135-139
312. Srivastava S, Ahmad AH, Thakur IS (2007) Removal of chromium and pentachlorophenol from tannery effluent. Biores Technol 98:1128-1132
313. Srivastava S, Thakur IS (2003) Bioadsorption potentiality of Acinetobacter sp. strain IST103 of a bacterial consortium for removal of chromium from tannery effluent. Biores Technol 97:1167-1173
314. Srivastava S, Thakur IS (2006) Biosorption potency of Aspergillus niger for removal of chromium (VI). Curr Microbiol 53(3):232-237
315. Srivastava S, Thakur IS (2007) Evaluation of biosorption potency of Acinetobacter sp. for removal of hexavalent chromium from tannery effluent. Biodegradation 18:637-646
316. Standeven AM, Wetterhahn KE (1991) Possible role of glutathione in chromium (VI) metabolism and toxicity in rats. Pharmacol Toxicol 68:469-476
317. Sugden KD, Geer RD, Rogers SJ (1992) Oxygen radical-mediated DNA damage by redox-Active Cr (III) complexes. Biochemistry 31:11626-11631
318. Sugiyama M (1992) Role of physiological antioxidants in chromium (VI)-induced cellular injury. Free Radical Biol Med 12:397-407
319. Sultan S, Hasnain S (2007) Reduction of toxic hexavalent chromium by Ochrobactrum intermedium strain SDCr-5 stimulated by heavy metals. Biores Technol 98(2):340-344
320. Suzuki T, Miyata N, Horitsu H, Kawai K, Tsakamizawa K, Tai Y, Okazaki M (1992) NAD(P)H dependent chromium (VI) reductase of Pseudomonas ambigua G-1: A Cr(V) intermediate is formed during the reduction of Cr (VI) to Cr(III). J Bacteriol 174:5340-5345
321. Szulczewski MD, Helmke PA, Bleam WF (1997) Comparison of XANES analysis and extractions to determine chromium speciation in contaminated soils. Environ Sci Technol 31:2954-2959
322. Tadesse I, Isoaho A, Green FB, Puhakka JA (2006) Lime enhanced chromium removal in advanced integrated wastewater pond system. Biores Technol 97(4):529-534
323. Tarangini K, Kumar A, Satpathy GR, Sangal VK (2009) Statistical optimization of process parameters for Cr (VI) biosorption onto mixed cultures of Pseudomonas aeruginosa and Bacillus subtilis Clean-Soil Air Water 37:319-327
324. Taseli BK, Gokcay CF (2005) Degradation of chlorinated compounds by Penicillium camemberti in batch and up-flow column reactors. Process Biochem 40:917-923
325. Thacker U, Parikh R, Shouche Y, Madamwar D (2006) Hexavalent chromium reduction by Providencia sp. Process Biochem 41:1332-1337
326. Thakur IS, Verma P, Upadhyaya KC (2001) Involvement of plasmid in degradation of pentachlorophenol by Pseudomonas sp. from a chemostat. Biochem Biophys Res Comm 286:109-113
327. The Environmental Protection Act (1991). Ministry of environment and land use. Government of Mauritius, Pat X, 182
328. Thorstensen EB (1958) Practice of chrome tannage. In: Flaherty FO, Roddy WT, Lollar RM (eds) The chemistry and technology of leather, American Chemical Society monograph series. Reinhold Publication Corporation, New York
329. Tobin JM, Cooper DG, Neufeld RJ (1984) Uptake of metal ions by Rhizopus arrhizus biomass. Appl Environ Microbiol 47:821-824
330. Trevors JT, Stratton GW, Gadd GM (1986) Cadmium transport, resistance, and toxicity in bacteria, algae, and fungi. Can J Microbiol 32:447-464
331. Tripathi M, Garg SK (2010) Studies on selection of efficient bacterial strain simultaneously tolerant to hexavalent chromium and pentachlorophenol isolated from treated tannery effluent. Res J Microbiol 5(8):707-716
332. Tripathi M, Mishra SS, Tripathi VR, Garg SK (2011a) Predictive approach for simultaneous biosorption of hexavalent chromium and pentachlorophenol degradation by Bacillus cereus RMLAU1. Afr J Biotechnol 10(32):6052-6061
333. Tripathi M, Vikram S, Jain RK, Garg SK (2011b) Isolation and growth characteristics of chromium (VI) and pentachlorophenol tolerant bacterial isolate from treated tannery effluent for its possible use in simultaneous bioremediation. Indian J Microbiol 51(1):61-69
334. Tucker MD, Barton LL, Thomson BM (1998) Reduction of Cr, Mo, Se and U by Desulfovibrio desulfuricans immobilized in polyacrylamide gels. J Ind Microbiol Biotechnol 20:13-19
335. Turick CE, Camp CE, Apel WA (1998) Bioremediation potential of Cr (VI) contaminated soil using indigenous microorganisms. Biorem J 2:1-6
336. Tziotzios G, Dermou E, Eftychia P, Dorothea V, Dimitris V (2008) Simultaneous phenol removal and biological reduction of hexavalent chromium in a packed-bed reactor. J Chem Technol Biotechnol 83(7):829-835
337. U.S. EPA (1979). Economics of wastewater treatment alternatives for the electroplating industry. In: U.S. EPA technology transfer report, Environment Protection Agency 625/5-79-016, June, U. S. Environmental Protection Agency, Washington
338. Uchiyama H, Yagi O, Oguri K, Kokufuta E (1994) Immobilization of trichloroethylene-degrading bacterium. Methylocystis sp. strain M in different matrices. J Ferment Bioeng 77:173-177
339. Ueno S (1992) Protective effects of thiol containing chelating agents against liver injury induced by hexavalent chromium in mice. Kitasato Arch Exp Med 65:87-96
340. Ueno S, Kashimoto T, Susa N, Furukawa Y, Ishii M, Yokoi K, Yasuno M, Sasaki YF, Ueda J-I, Nishimura Y, Sugiyama M (2001) Detection of dichromate (VI)-induced DNA strand breaks and formation of paramagnetic chromium in multiple mouse organs. Toxicol Appl Pharmacol 170:56-62
341. Urrutia MM (1997) General bacterial sorption processes. In: Waste J, Forster C (eds) Biosorbent for metal ions. Taylor and Francis Publishers, London, pp 39-66
342. Valdman E, Erijman L, Pessoa FLP, Leite SGF (2001) Continuous biosorption of Cu and Zn by immobilized waste biomass Sargassum sp. Process Biochem 36:869-873
343. van Hullebusch ED, Zandvoort MH, Lens PNL (2003) Metal immobilization by biofilms: Mechanisms and analytical tools. Rev Environ Sci Bio/Technol 2:9-33
344. Veglio F, Beolchini F (1997) Removal of metals by biosorption: A review. Hydrometallurgy 44:301-316
345. Venba R, Jawahar M, Babu NKC (1999) Studies on the effect of recovered chrome on dyeing of leathers. Proceedings of the XXV IULTCS Congress. Tata McGraw-Hill Publishers, New Delhi, pp 446-452
346. Venitt S, Levy LS (1974) Mutagenicity of chromates in bacteria and its relevance to chromate carcinogenesis. Nature (Lond) 250:493-495
347. Verma SK, Singh RK (1995) Multiple metal resistance in the cyanobacterium Nostoc muscorum Bull Environ Contam Toxicol 54:614-619
348. Verma T, Garg SK, Ramteke PW (2009) Genetic correlation between chromium resistance and reduction in Bacillus brevis isolated from tannery effluent. J Appl Microbiol 107:1425-1432
349. Verschoor MA, Braget PC, Herber RFM, Zielhuis RL, Zwennis WCM (1988) Renal function of chrome-plating workers and welders. Int Arch Occup Environ Health 60:67-70
350. Viamajala S, Peyton BM, Petersen JN (2003) Modeling chromate reduction in Shewanella oneidensis MR-1: Development of a novel dual-enzyme kinetic model. Biotechnol Bioeng 83:790-797
351. Viamajala S, Peyton R, Apel WA, Petersen JN (2002) Chromate/nitrite interactions in Shewanella oneidensis MR-1: Evidence for multiple hexavalent chromium [Cr (VI)] reduction mechanisms dependent on physiological growth conditions. Biotechnol Bioeng 78:770-778
352. Vidali M (2001) Bioremediation. An overview. Pure Appl Chem 73(7):1163-1172
353. Viraraghavan T, Kapoor A (1998) Removal of heavy metals from aqueous solutions using immobilized fungal biomass in continuous mode. Water Res 32:1968-1977
354. Viti C, Pace A, Giovanetti L (2003) Characterization of Cr (VI)-resistant bacteria isolated from chromium-contaminated soil by tannery activity. Curr Microbiol 46:1-5
355. Volesky B (1990) Biosorption and biosorbents. In: Volesky B (ed) Biosorption of heavy metals. CRC, Boca Raton
356. Volesky B, Holan ZR (1995) Biosorption of heavy metals. Biotechnol Prog 11:235-250
357. Walker SG, Flemming CA, Ferris FG, Beveridge TJ, Bailey GW (1989) Physicochemical interaction of Escherichia coli cell envelopes and Bacillus subtilis cell walls with two clays and the ability of the composite to immobilize heavy metals from solution. Appl Environ Microbiol 55:2976-2984
358. Wang PC, Mori T, Komori K, Sasatu M, Toda K, Ohtake H (1989) Isolation and characterization of an Enterobacter cloacae strain that reduces hexavalent chromium under anaerobic conditions. Appl Environ Microbiol 55:1665-1669
359. Wang PC, Mori T, Toda K, Ohtake H (1990) Membrane-Associated chromate activity from Enterobacter cloacae J Bacteriol 172:1670-1672
360. Wang PC, Toda K, Ohtake H, Kusaka I, Yabe I (1991) Membrane-bound respiratory system of Enterobacter cloacae strain H01 grown anaerobically with chromate. FEMS Microbiol Lett 78:11-16
361. Wang Y, Xu W, Luo Y, Ma L, Li Y, Yang S, Huang K (2009) Bioeffects of chromium (III) on the growth of Spirulina platensis and its biotransformation. J Sci Food Agric 89(6):947-952
362. Wang YT, Chirwa EM (1998) Simultaneous removal of Cr (VI) and phenol in chemostat culture of E. coli ATCC 33456 and P. putida DMP-1. Water Sci Technol 38:113-119
363. Wang YT, Nikhalambayausi-Chirwa EM (2001) Simultaneous Cr (VI) reduction and phenol degradation in a fixed-film coculture bioreactor: reactor performance. Water Res 35:1951-1932
364. Wang YT, Shen H (1995) Bacterial reduction of hexavalent chromium. J Ind Microbiol 14:159-163
365. Wang YT, Xiao CS (1995) Factors affecting hexavalent chromium reduction in pure cultures of bacteria. Water Res 29(11):2467-2474
366. Weber WJ Jr (1985) Adsorption theory, concepts and models. In: Slejko FL (ed) Adsorption technology: A step-by-step approach to process evaluation and application. Marcel Dekker, New York, pp 1-35
367. White C, Gadd GM (1997) An internal sedimentation bioreactor for laboratory-scale removal of toxic chemicals from leachates using biogenic sulfide precipitation. J Ind Microbiol Biotechnol 18:414-421
368. White C, Gadd GM (1998) Accumulation and effects of cadmium on sulfate-reducing bacterial films. Microbiology 144:1407-1415
369. WHO (1988) Environmental health criteria 61. Chromium. World Health Organisation, Geneva, p 197
370. Wilhelmi BS, Duncan JR (1995) Metal recovery from Saccharomyces cerevisiae biosorption columns. Biotechnol Lett 17:1007-1012
371. Wilson JA (1948) Modern practice in leather manufacture. Reinhold Publishing Corporation, New York
372. Wong PK, So CM (1993) Copper accumulation by a strain of Pseudomonas putida Microbios 73:113-121
373. Xing L, Okrent D (1993) Future risk from a hypothesized RCRA site disposing of carcinogenic metals should a loss of societal memory occur. J Hazard Mater 38:363-384
374. Xu WH, Liu YG (2005) Experimental study on Cr (VI) reduction by Pseudomonas aeruginosa Environ Sci Technol 28:1-3
375. Xu WH, Liu YG, Zeng GM, Li X, Song HX, Peng QQ (2009) Characterization of Cr (VI) resistance and reduction by Pseudomonas aeruginosa Trans Nonf Met Soc China 19:1336-1341
376. Xu XR, Li HB, Gu J-D (2004) Reduction of hexavalent chromium by ascorbic acid in aqueous solutions. Chemosphere 57:609-613
377. Xu XR, Li HB, Gu J-D, Li XY (2005) Kinetics of the reduction of chromium (VI) by vitamin C. Environ Toxicol Chem 24:1310-1314
378. Yang CF, Lee CM, Wang CC (2006) Isolation and physiological characterization of the pentachlorophenol degrading bacterium Sphingomonas chlorophenolica Chemosphere 69:709-714
379. Yang RD, Humphrey AE (1975) Dynamic and steady state studies of phenol biodegradation in pure and mixed cultures. Biotechnol Bioeng 17:1211-1235
380. Yao J, Tian L, Wang Y, Djah A, Wang F, Chen H, Su C, Zhuang R, Zhou Y, Choi MM, Barmanti E (2008) Microcalorimetric study the toxic effect of hexavalent chromium on microbial activity of Wuhan brown sandy soil: An in vitro approach. Ecotoxicol Environ Saf 69:289-295
381. Yassi A, Nieboer E (1988) Carcinogenicity of chromium compounds. In: Nriagu JO, Neiboer E (eds) Chromium in the natural and human environments. Wiley, New York, pp 443-496
382. Yuann JP, Liu KJ, Hamilton J-W, Wetterhahn KE (1999) In vivo effects of ascorbate and glutathione on the uptake of chromium, formation of chromium (V), chromium-DNA binding and 8-hydroxyl-2'-deoxy-guanosine in liver and kidney of osteogenic disorder shionogi rats following treatment with chromium (VI). J Carcinogen 20:1267-1275
383. Zayed AM, Terry N (2003) Chromium in the environment: Factors affecting biological remediation. Plant Soil 249:139-156
384. Zhao M, Duncan JR (1998) Column sorption of Cr (VI) from electroplating effluent using formaldehyde cross-linked Sacchromyces cerevisae Biotechnol Lett 20(6):603-606
385. Zhao Y, Zouboulis AI, Matis KA (1996) Removal of molybdate and arsenate from aqueous solutions by floatation. Sep Sci Technol 31:769-785