Screening and growth optimization of 2,4-dimethylphenol degrading bacteria
As an intermediate in producing many industrial and agricultural products,2,4-dimethylphenol accumulates in large quantities in the environment.Due to its difficulty in natural degradation,it causes par-ticular environmental pollution and is an essential ecological priority pollutant.In this study,a strain 4302,which can efficiently degrade 2,4-dimethylphenol,was isolated from the activated sludge of a wastewater treatment factory.After morphological observation,biochemical identification,and 16S rRNA sequence a-nalysis,the strain was identified as Comamonas sp.,and named Comamonas sp.4302.The strain 4302 could completely degrade 2 mmol/L of 2,4-dimethylphenol within 24 hours.Based on the results of single-factor experiments,response surface experiments were conducted to optimize the growth conditions of strain 4302.The results showed that the optimal conditions for the growth of strain 4302 were:temperature 31.7 ℃,pH 7.4,substrate concentration 0.9 mmol/L,and culture for 14 hours after inoculation,OD600 could reach 0.117.The enzyme activity of strain 4302 showed that protocatechuate 3,4-dioxygenase was detected,but catechol 2,3-dioxygenase and gentisate 1,2-dioxygenase were not detected,suggesting that the metabolic pathway of 2,4-dimethylphenol in strain 4302 might be through protocatechuate ring-open-ing.This study provides a scientific theoretical reference for the microbial reserve for the degradation of 2,4-dimethylphenol and the remediation of polluted environment.
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