不适宜生长条件对混菌降解苯胺的影响

分别从台州和衢州某化工厂的好氧池中分离筛选得到2株苯胺降解菌TZ1和JH1,经16S rDNA测序鉴定为Comamonas sp.TZ1和Pseudomonas sp.JH1,均具有较强的苯胺降解能力,培养24 h后,可使初始浓度为800 mg/L的苯胺去除率达到96.4%~98.4%。在此基础上,按体积比1∶1将2株菌液进行混合构建了混合菌体系,进而对比考察了苯胺初始浓度、pH、盐度和重金属等环境因子对单一菌和混合菌生长量及降解苯胺效果的影响,重点探讨混合菌对不适宜生长环境的适应性及其对苯胺的降解特性。通过单一菌和混合菌对比实验发现,在适宜苯胺初始浓度、pH和盐度条件下,混合菌的生长量略高于单一菌;在不适宜生长的高浓度苯胺、pH和盐度条件下,混合菌也表现出了更强的适应性和苯胺矿化能力。Zn2+和Cr6+耐受实验则表明,对于Cr6+,混合菌表现出了更强的耐受能力,而对于Zn2+并没有表现出更强的耐受能力。

Effects of unsuitable growth conditions on mixed strains for aniline degradation

Aniline-degrading strain TZ1 and JH1 were isolated from the sludge of the aeration tank of chemical plants in Quzhou and Taizhou,respectively,and they were identified as Comamonas sp.TZ1 and Pseudomonas sp.JH1 by 16S rDNA gene sequencing.After a culture for 24 h,either of the two strains could degrade 96.4%~98.4% aniline with an initial aniline concentration of 800 mg/L,which showed strong aniline-degradation ability.Then,two strains were mixed in ratio of 1:1 to develop an effective bacterial consortium,and the impact of initial concentration of aniline,pH,salinity and heavy metals on the growth and aniline degradation was investigated.Compared with two independent strains,the mixed consortium showed higher growth under appropriate initial aniline concentration,pH and salinity conditions.Furthermore,the mixed strains showed much higher adaptability and stronger aniline-biodegradation capability than two single strains in the harsh environment with high aniline concentrations,pH unsuitable for growth and high salinity.In addition,the mixed consortium had stronger tolerance to Cr⁶⁺ stress,while the difference was not very obvious for Zn²⁺.