title: Enhancing gold recovery from electronic waste via lixiviant metabolic engineering in Chromobacterium violaceum.
abstract: Conventional leaching (extraction) methods for gold recovery from electronic waste involve the use of strong acids and pose considerable threat to the environment. The alternative use of bioleaching microbes for gold recovery is non-pollutive and relies on the secretion of a lixiviant or (bio)chemical such as cyanide for extraction of gold from electronic waste. However, widespread industrial use of bioleaching microbes has been constrained by the limited cyanogenic capabilities of lixiviant-producing microorganisms such as Chromobacterium violaceum. Here we show the construction of a metabolically-engineered strain of Chromobacterium violaceum that produces more (70%) cyanide lixiviant and recovers more than twice as much gold from electronic waste compared to wild-type bacteria. Comparative proteome analyses suggested the possibility of further enhancement in cyanogenesis through subsequent metabolic engineering. Our results demonstrated the utility of lixiviant metabolic engineering in the construction of enhanced bioleaching microbes for the bioleaching of precious metals from electronic waste.
authors.affiliation: Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore.
authors.forename: Song Buck
authors.initials: SB
authors.lastname: Tay
authors.forename: Gayathri
authors.initials: G
authors.lastname: Natarajan
authors.forename: Muhammad Nadjad bin Abdul
authors.initials: MN
authors.lastname: Rahim
authors.forename: Hwee Tong
authors.initials: HT
authors.lastname: Tan
authors.forename: Maxey Ching Ming
authors.initials: MC
authors.lastname: Chung
authors.forename: Yen Peng
authors.initials: YP
authors.lastname: Ting
authors.forename: Wen Shan
authors.initials: WS
authors.lastname: Yew
mesh_terms: D002861:Chromobacterium / Q000235:genetics / Q000378:metabolism*; D003486:Cyanides / Q000378:metabolism; D059029:Electronic Waste; D023061:Gene Order; D005818:Genetic Engineering; D005822:Genetic Vectors / Q000235:genetics; D006046:Gold; D060847:Metabolic Engineering; D053858:Metabolic Networks and Pathways; D040901:Proteomics; D018505:Waste Management
chemical_list: D003486:Cyanides; D006046:Gold