Optimized culture medium and fermentation conditions for enzyme production by the atrazine-degrading bacterium HB-5
莠去津降解菌HB-5的最佳产酶培养基及发酵条件

An atrazine degrading bacterium (Arthrobacter sp.) HB-5, was isolated in our laboratory from pesticide waste water. The optimum fermentation conditions and fermentation culture medium of HB-5 were selected by uniform experimental design and orthogonal experimentation, and the amount of enzyme produced by HB-5 was estimated from the atrazine degradation rate. The experimental results were analyzed by the SASsystem. The ideal composition of culture medium of HB-5 included saccharose 3.0 g·L-1, atrazine 0.38 g·L-1, K2HPO4 1.2 g·L-1, K2HPO4 0.5 g·L-1, MgSO4· 7H2O1.2 g·L-1, NaCl 0.1 g·L-1,microelements 3.8 mL·L-1. The optimum culture conditions of HB-5 were: culture time 48 h, inoculum size 2%, initial pH9.0 and amount of culture medium 80 mL. The degradation rate of atrazine by the optimum fermentation liquid reached up to 91.64%, and increased 125% over the original culture medium (40.67%).