title: Improvement of chromium biosorption by UV-HNO(2) cooperative mutagenesis in Candida utilis.
abstract: The present study focused on the improvement of chromium resistance and biosorption efficiency in Candida utilis CR-001 utilizing protoplast mutagenesis technology. Through ultraviolet (UV) radiation, HNO(2) treatment and chromium acclimatization, six preferred mutants of C. utilis CR-001 were screened out, namely, CRU132-26, CRC7-2, CRC2811-1, CRC2811-2, CRC2814-8 and CRY182-1. The removal efficiency of these mutants for 20mg/L Cr(VI) solutions were 85.6%, 95.2%, 87.0%, 82.5%, 94.7% and 82.7%, respectively, noticeably greater than that of the parent strain CR-001 (79.5%). Furthermore, CRC2811-1 exhibited outstanding application potential with high removal efficiency and low dosage over a wide range of pH. Cell surface and inner details of CRC2811-1 and its parent strain CR-001 were analyzed by scanning electron microscopy (SEM) and atomic force microscopy (AFM) in order to explore possible changes caused by inducement. The results showed that Cr-sorption of CR-001 mainly depended on intracellular accumulation, but for CRC2811-1, cell surface deposition was also involved in improving its chromium biosorption capacity.
authors.affiliation: Department of Environmental Engineering, Jinan University, Guangzhou 510632, China. thyin@jnu.edu.cn
authors.forename: Hua
authors.initials: H
authors.lastname: Yin
authors.forename: Baoyan
authors.initials: B
authors.lastname: He
authors.forename: Xianyan
authors.initials: X
authors.lastname: Lu
authors.forename: Hui
authors.initials: H
authors.lastname: Peng
authors.forename: Jinshao
authors.initials: J
authors.lastname: Ye
authors.forename: Feng
authors.initials: F
authors.lastname: Yang
mesh_terms: D000042:Absorption; D002175:Candida / Q000235:genetics* / Q000648:ultrastructure; D002857:Chromium / Q000737:chemistry / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D016296:Mutagenesis; D009573:Nitrites / Q000737:chemistry*; D014466:Ultraviolet Rays; D018508:Water Purification
chemical_list: D009573:Nitrites; D002857:Chromium