Enhancement of cypermethrin degradation by a coculture of Bacillus cereus ZH-3 and Streptomyces aureus HP-S-01.
Degradation of cypermethrin was significantly enhanced in a coculture of Bacillus cereus ZH-3 and Streptomyces aureus HP-S-01. In the pure culture, longer half-lives (t(1/2)=32.6-43.0h) of cypermethrin were observed, as compared to the mixed cocultures (t(1/2)=13.0h). The optimal degradation conditions were determined to be 28.2°C and pH 7.5 based on response surface methodology (RSM). Under these conditions, the mixed cultures completely metabolized cypermethrin (50mgL(-1)) within 72h. Analysis of degradation products of cypermethrin indicated that the microbial consortium converted cypermethrin to α-hydroxy-3-phenoxy-benzeneacetonitrile, 3-phenoxybenzaldehyde and 4-phenoxyphenyl-2,2-dimethyl-propiophenone, and subsequently transformed these compounds with a maximum specific degradation rate (q(max)), half-saturation constant (K(s)) and inhibition constant (K(i)) of 0.1051h(-1), 31.2289mgL(-1) and 220.5752mgL(-1), respectively. This is the first report of a proposed pathway of degradation of cypermethrin by hydrolysis of ester linkage and oxidization of 3-phenoxybenzyl in a coculture. Finally, this coculture is the first described mixed microbial consortium capable of metabolizing cypermethrin.
Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, Laboratory of Insect Toxicology, South China Agricultural University, Guangzhou 510642, PR China.
Shaohua
S
Chen
Jianjun
J
Luo
Meiying
M
Hu
Kaiping
K
Lai
Peng
P
Geng
Huasheng
H
Huang
D001409:Bacillus cereus / Q000378:metabolism*; D018920:Coculture Techniques; D006863:Hydrogen-Ion Concentration; D007306:Insecticides / Q000378:metabolism*; D011722:Pyrethrins / Q000378:metabolism*; D013302:Streptomyces / Q000378:metabolism*; D013696:Temperature
D007306:Insecticides; D011722:Pyrethrins; C017160:cypermethrin