苯系化合物降解的微生物筛选及其特性初探

为选育高效降解苯系物的菌株,该研究选用污水处理厂处理废水的活性污泥作为菌源,分别以甲苯、乙苯、二甲苯作为底物,在好氧条件下,驯化、筛选和分离出了能以上述化合物作为生长的唯一碳源和能源的微生物菌株,并对其进行了初步的鉴定,分别是假单细胞菌属(Pseudomonas sp.)、芽孢杆菌属(Bacillus sp.)、红球菌属(Rhodococcus sp.)等。结果表明,对甲苯的降解率可以达到95%～98%,对乙苯的降解率为80%～88%,对二甲苯的降解率维持在70%～80%之间。进一步研究表明混合菌的最佳生长条件为培养温度30℃,培养时间48 h,接种量10%,摇床转速180 r/min,降解甲苯、乙苯时的pH为7～9,降解二甲苯时的pH为4或10。

Screening of Microbe and Its Characteristics for Benzene Compounds Degradation

To select efficient strains which was used to degrade benzene compounds, the study selected activated sludge as a bacteria source in Shanghai Jinshan chemical industry zone sewage treatment plant, toluene, ethylbenzene and xylene as substrates separately. Under aerobic conditions, the micro-strains were isolated that can live upon above-mentioned compounds as the sole growth carbon and energy source. The micro-strains are preliminary identified as Pseudomonas sp., Bacillus sp., Rhodococcus sp., etc. Aerobic biodegradation study showed that the degradation efficiency of toluene can reach 95 %-98 %, which of ethylbenzene can reach 80 % -88 % and which of p-xylene can reach 70 %-80 %. The optimal growth conditions for hybrid bacteria are 30 ℃, reaction time 48 h, inoculation 10 %, shaking rotate 180 r/min, pH 7-9 for toluene, ethylbenzene degradation and pH 4 or 10 for xylene degradation, respectively.