摘要
土臭素（geosmin，GSM）和2-甲基异冰片（2-methylisoborneol，2-MIB）是2种普遍存在于养殖水体中的土腥异味化合物，微生物降解是去除这两种物质的有效途径．本文研究了枯草芽孢杆菌（Bacillussubtilis）降解GSM和2-MIB的动力学特性．结果表明，枯草芽孢杆菌对GSM（1000～2000ng·L^-1）和2-MIB（1000～2000ng·L^-1）具有较好的降解性能，降解率均达90％以上；枯草芽孢杆菌对这些异味化合物的降解符合伪一级反应动力学，其生物降解速率常数（足）范围为0．14～0．41，降解速率不随GSM和MIB初始浓度的变化而变化；枯草芽孢杆菌对GSM降解的最大比生长速率umax为0．311，Monod常数K；为1．73，而在降解MIB过程中枯草芽孢杆菌的生长不符合Monod方程（R^2=0．781）．
The earthy and musty odor problem in aquaculture systems has been a worldwide problem, especially in freshwater aquaculture systems. Geosmin （GSM） and 2-methylisoborneol （2-MIB） , the most common causative agents of the off-flavor in fish, are lipophilic secondary metabolites of cyanobacteria, actinomycetes, and other microorganisms. The odor threshold concentrations for 2-MIB and GSM are approximately 9-42 ng·L^-1 and 4-10 ng·L^-1 , and 600 ng·kg^-1 and 900 ng·kg^-1 in the aquaculture water and fish, respectively. With such a low odor threshold concentration, the off-flavor compounds greatly reduce the quality and economic value of aquatic products. This renders the fish, especially some valuable fish produced in reeirculating aquaculture systems （RAS） ; unmarketable. The study reported the kinetic characteristics of degradation of GSM and 2-MIB by Bacillus subtilis and discussed the impacts of the initial concentration of GSM and 2-MIB （ T1, T2） and inoculation amount （ T1, T3） on the biodegradation rate. The result demonstrated that these two compounds could be degraded by B. subtilis effectively and the biodegradation rate reached more than 90% in T1, T2 and T3 treatments. The biodegradation of these two compounds behaved as a pseudo-first-order kinetics with rate constants （K） in the range of 0. 14-0.41. K values indicated that the degradation rate was dependent on the inoculation amount but the start concentration of GSM and MIB. The degradation kinetics showed the maximum specific rate value （ Umax） and the Monod constant （ Ks ） were 0.311 and 1. 73, however, 2-MIB degradation process did not meet the Monod microbial growth equation （R^2 = 0.781 ）.
出处
《环境科学》
EI
CAS
CSCD
北大核心
2015年第4期1379-1384,共6页
Environmental Science
基金
上海工程技术中心能力提升项目(13DZ2280500)
关键词
枯草芽孢杆菌
土臭素
2-甲基异冰片
土腥异味化合物
降解
动力学
Bacillus subtilis
geosmin （ GSM ）
2-methylisoborneol （2-MIB）
off-flavor compounds
degradation
kinetics
