产酸克雷伯氏菌Klebsiella oxytoca对硝基苯及4-氯硝基苯的降解

硝基苯类化合物生物降解菌的筛选及性能研究，是制药、染料等行业废水达标的重要基础。以浓度梯度升高法筛选到一株硝基苯厌氧降解菌Klebsiella oxytoca NBA-1。考察了该菌对氧气的需求，以及在厌氧条件下，温度、pH值、外加葡萄糖及硝基苯初始浓度等环境因子对菌株降解硝基苯能力的影响，并进一步讨论菌株对氯取代硝基苯类化合物的降解情况。结果表明，该菌在厌氧条件下生长比好氧条件下慢，但降解速度更快；厌氧降解硝基苯的最佳pH值和温度和分别为8．3和30～35℃；加入0．3％～0．5％的葡萄糖可促进降解，且对300mg／L以下的硝基苯均有降解能力；该菌能将4-氯硝基苯转化为4-氯苯胺，并进一步脱氯为苯胺。研究结果可为硝基苯及含氯硝基苯的处理工艺选择提供相关的参考依据。

Degradation of nitrobenzene and 4-chloronitrobenzene by Klebsiella oxytoca

The screening and characterization of nitrobenzene-degrading microorganisms are the safe foundation for the wastewater discharged from the pharmaceutical and dye factories. An anaerobic nitrobenzene-degrading bacterium was isolated through gradient concentrations increasing method and was named as Klebsiella oxytoca NBA-1. The impacts of environmental factors such as oxygen demand, temperatures, pH, extra glucose addition and different initial concentrations of nitrobenzene were examined under anaerobic condition to study the degradation ability of this strain. Besides,the biodegradation ability and pathway of 4-chloronitrobenzene were in- vestigated. The results showed that the biodegradation rate under anaerobic condition by NBA-1 was faster than that of aerobic condition whereas the growth rate under anaerobic condition was slower than under aerobic condition. 300 mg/L nitrobenzene could be degraded when pH was 8.3 with 0.3% -0.5% glucose at 30 -35℃ under anaerobic condition. Klebsiella oxytoca NBA-1 can transform 4-chloronitrobenzene into 4-chloroaniline, and dechlorinate to aniline continually. The results may provide reference for the process of nitrobenzene and chloro- nitrobenzene containing wastewater treatment.