title: Biological decolorization of malachite green by Deinococcus radiodurans R1.
abstract: Cultures of Deinococcus radiodurans R1 were observed to decolorize malachite green (MG) dye. The effects of various factors on decolorization efficiency were investigated. The optimal decolorization temperature and pH ranges were 25-50°C and 6.0-8.0, respectively. With increasing initial MG concentration, the decolorization efficiency decreased, and the kinetic parameters, R(MG,max) and K(m) were 416.7 mg-MG/g-cell/h and 1033.7 mg/L, respectively. The D. radiodurans R1 cells were capable of tolerating and rapidly degrading high concentrations of the dye. When MG concentration was 200 mg/L, decolorization efficiency was up to 97.2% within 30 min. The intermediate products of MG biodegradation were 4-(dimethylamino)phenol and 4-(dimethylamino)benzophenone, as identified by gas chromatography/mass spectrometry analysis. Toxicity tests indicated that D. radiodurans R1 did not detoxify an MG solution completely, but clearly reduced its toxicity. This study demonstrated that this strain was an efficient degrader compared to other microorganisms.
authors.affiliation: Institute of Horticulture, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China.
authors.forename: Guo-Ying
authors.initials: GY
authors.lastname: Lv
authors.forename: Jian-Hui
authors.initials: JH
authors.lastname: Cheng
authors.forename: Xiao-Yang
authors.initials: XY
authors.lastname: Chen
authors.forename: Zuo-Fa
authors.initials: ZF
authors.lastname: Zhang
authors.forename: Lei-Fa
authors.initials: LF
authors.lastname: Fan
mesh_terms: D000818:Animals; D001673:Biodegradation, Environmental / Q000187:drug effects; D003116:Color; D034301:Deinococcus / Q000187:drug effects / Q000378:metabolism*; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D007700:Kinetics; D008163:Luminescent Measurements; D051379:Mice; D012394:Rosaniline Dyes / Q000302:isolation & purification* / Q000633:toxicity; D013696:Temperature; D018675:Toxicity Tests
chemical_list: D012394:Rosaniline Dyes; C005095:malachite green
keywords: Biodegradation; Decolorization; Deinococcus radiodurans; Malachite green