title: Efficient biodegradation of cyanide and ferrocyanide by Na-alginate beads immobilized with fungal cells of Trichoderma koningii.
abstract: Cyanide or metal cyanide contaminations have become serious environmental and food-health problems. A fungal mutant of Trichoderma koningii, TkA8, constructed by restriction enzyme-mediated integration, has been verified to have a high cyanide degradation ability in our previous study. In this study, the mutant cells were entrapped in sodium-alginate (Na-alginate) immobilization beads to degrade cyanide and ferrocyanide in a liquid mineral medium. The results showed that the fungus in immobilization beads consisting of 3% Na-alginate and 3% CaCl2 could degrade cyanide more efficiently than a nonimmobilized fungal culture. For maximum degradation efficiency, the optimal ratio of Na-alginate and wet fungal biomass was 20:1 (m/m) and the initial pH was 6.5. In comparison, cell immobilization took at least 3 and 8 days earlier, respectively, to completely degrade cyanide and ferrocyanide. In addition, we showed that the immobilized beads could be easily recovered from the medium and reused for up to 5 batches without significant losses of fungal remediation abilities. The results of this study provide a promising alternative method for the large-scale remediation of soil or water systems from cyanide contamination.
authors.affiliation: Department of Plant Science, School of Agriculture and Biology, Shanghai Jiaotong University, 2678 Qixin Road Shanghai, 201101 People's Republic of China.
authors.forename: Xiaoying
authors.initials: X
authors.lastname: Zhou
authors.forename: Lixing
authors.initials: L
authors.lastname: Liu
authors.forename: Yunpeng
authors.initials: Y
authors.lastname: Chen
authors.forename: Shufa
authors.initials: S
authors.lastname: Xu
authors.forename: Jie
authors.initials: J
authors.lastname: Chen
mesh_terms: D000464:Alginates; D001673:Biodegradation, Environmental; D001709:Biotechnology / Q000379:methods*; D018914:Cells, Immobilized; D003470:Culture Media; D003486:Cyanides / Q000378:metabolism*; D005295:Ferrocyanides / Q000378:metabolism*; D020723:Glucuronic Acid; D006603:Hexuronic Acids; D008863:Microspheres; D012989:Soil Pollutants / Q000378:metabolism; D014242:Trichoderma / Q000166:cytology* / Q000235:genetics / Q000378:metabolism; D014873:Water Pollutants / Q000378:metabolism
chemical_list: D000464:Alginates; D003470:Culture Media; D003486:Cyanides; D005295:Ferrocyanides; D006603:Hexuronic Acids; D012989:Soil Pollutants; D014873:Water Pollutants; D020723:Glucuronic Acid; C020354:hexacyanoferrate II