title: Effective bioleaching of chromium in tannery sludge with an enriched sulfur-oxidizing bacterial community.
abstract: In this study, a sulfur-oxidizing community was enriched from activated sludge generated in tannery wastewater treatment plants. Bioleaching of tannery sludge containing 0.9-1.2% chromium was investigated to evaluate the effectiveness of the enriched community, the effect of chromium binding forms on bioleaching efficiency, and the dominant microbes contributing to chromium bioleaching. Sludge samples inoculated with the enriched community presented 79.9-96.8% of chromium leaching efficiencies, much higher than those without the enriched community. High bioleaching efficiencies of over 95% were achieved for chromium in reducible fraction, while 60.9-97.9% were observed for chromium in oxidizable and residual fractions. Acidithiobacillus thiooxidans, the predominant bacteria in the enriched community, played an important role in bioleaching, whereas some indigenous heterotrophic species in sludge might have had a supporting role. The results indicated that A. thiooxidans-dominant enriched microbial community had high chromium bioleaching efficiency, and chromium binding forms affected the bioleaching performance.
authors.affiliation: College of Architecture and Environment, Sichuan University, No. 24, South Section 1, First Ring Road, Chengdu, Sichuan 610065, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Zeng
authors.affiliation: College of Architecture and Environment, Sichuan University, No. 24, South Section 1, First Ring Road, Chengdu, Sichuan 610065, China.
authors.forename: Min
authors.initials: M
authors.lastname: Gou
authors.affiliation: College of Architecture and Environment, Sichuan University, No. 24, South Section 1, First Ring Road, Chengdu, Sichuan 610065, China. Electronic address: tangyq@scu.edu.cn.
authors.forename: Yue-Qin
authors.initials: YQ
authors.lastname: Tang
authors.affiliation: College of Light Industry, Textile and Food Engineering, Sichuan University, No. 24, South Section 1, First Ring Road, Chengdu, Sichuan 610065, China.
authors.forename: Guo-Ying
authors.initials: GY
authors.lastname: Li
authors.affiliation: College of Architecture and Environment, Sichuan University, No. 24, South Section 1, First Ring Road, Chengdu, Sichuan 610065, China.
authors.forename: Zhao-Yong
authors.initials: ZY
authors.lastname: Sun
authors.affiliation: College of Architecture and Environment, Sichuan University, No. 24, South Section 1, First Ring Road, Chengdu, Sichuan 610065, China.
authors.forename: Kenji
authors.initials: K
authors.lastname: Kida
mesh_terms: D013856:Acidithiobacillus thiooxidans / Q000378:metabolism*; D001673:Biodegradation, Environmental; D002857:Chromium / Q000032:analysis / Q000737:chemistry / Q000378:metabolism; D007220:Industrial Waste; D010084:Oxidation-Reduction; D013633:Tanning
chemical_list: D007220:Industrial Waste; D002857:Chromium
keywords: Acidithiobacillus thiooxidans; Bioleaching; Chromium binding forms; Sulfur-oxidizing bacteria; Tannery sludge