Isolation and degradation characteristics of nitrobenzene degradation bacterium under hypersaline conditions

Six high efficiency nitrobenzene degradation strains were isolated and screened from activated sludge of aeration tank in a pharmaceutical factory under the hypersaline conditions.Among the six degradation strains,N18 presented the best nitrobenzene biodegradation capability.According to the morphological characteristics,physiological and biochemical characteristics,the strain N18 was identified as Corynebacterium sp.Results of nitrobenzene degradation experiments showed that the optimal N18 culture conditions were 30 ℃,pH 7 and shaker rotary speed 150 r/min.When the initial nitrobenzene concentration was below 150 mg/L,the nitrobenzene degradation rate of N18 was higher than 75% after 72 h of cultivation.In addition,the influence of salinity on nitrobenzene degradation rate was not obvious when salinity ranged 1%-3%,while the strain could hardly grow when the salinity up to 10%,so N18 was belonged to medium salt-tolerance strain.