title: Rhamnolipid-aided biodegradation of carbendazim by Rhodococcus sp. D-1: Characteristics, products, and phytotoxicity.
abstract: We successfully isolated Rhodococcus sp. D-1, an efficient carbendazim-degrading bacterium that degraded 98.20% carbendazim (200ppm) within 5days. Carbendazim was first processed into 2-aminobenzimidazole, converted to 2-hydroxybenzimidazole, and then further mineralized by subsequent processing. After genomic analysis, we hypothesized that D-1 may express a new kind of enzyme capable of hydrolyzing carbendazim. In addition, the effect of the biodegradable biosurfactant rhamnolipid on the rate and extent of carbendazim degradation was assessed in batch analyses. Notably, rhamnolipid affected carbendazim biodegradation in a concentration-dependent manner with maximum biodegradation efficiency at 50ppm (at the critical micelle concentration, CMC) (97.33% degradation within 2days), whereas 150ppm (3 CMC) rhamnolipid inhibited initial degradation (0.01%, 99.26% degradation within 2 and 5days, respectively). Both carbendazim emulsification and favorable changes in cell surface characteristics likely facilitated its direct uptake and subsequent biodegradation. Moreover, rhamnolipid facilitated carbendazim detoxification. Collectively, these results offer preliminary guidelines for the biological removal of carbendazim from the environment.
authors.affiliation: Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou 310058, PR China.
authors.forename: Naling
authors.initials: N
authors.lastname: Bai
authors.affiliation: Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou 310058, PR China.
authors.forename: Sheng
authors.initials: S
authors.lastname: Wang
authors.affiliation: Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou 310058, PR China.
authors.forename: Rexiding
authors.initials: R
authors.lastname: Abuduaini
authors.affiliation: Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou 310058, PR China.
authors.forename: Meinan
authors.initials: M
authors.lastname: Zhang
authors.affiliation: Institute of Genetics, College of Life Sciences, Zhejiang University, Hangzhou 310058, PR China.
authors.forename: Xufen
authors.initials: X
authors.lastname: Zhu
authors.affiliation: Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou 310058, PR China. Electronic address: yhzhao225@zju.edu.cn.
authors.forename: Yuhua
authors.initials: Y
authors.lastname: Zhao
mesh_terms: D001562:Benzimidazoles / Q000378:metabolism*; D001673:Biodegradation, Environmental; D002219:Carbamates / Q000378:metabolism*; D006017:Glycolipids / Q000737:chemistry*; D012240:Rhodococcus / Q000378:metabolism*; D013501:Surface-Active Agents / Q000737:chemistry*
chemical_list: D001562:Benzimidazoles; D002219:Carbamates; D006017:Glycolipids; D013501:Surface-Active Agents; C418382:rhamnolipid; C006698:carbendazim
keywords: Biodegradation; Carbendazim; Cell surface hydrophobicity; Detoxification; Rhamnolipid; Zeta potential