三苯基锡吸附降解菌的分离及特性研究

Isolation and Characteristics of Triphenyltin-Biosorption and Biodegradation Strain

通过菌种筛选和吸附降解特性实验,分离三苯基锡（TPhT）的吸附降解菌,研究TPhT的微生物吸附降解性能和机制.结果表明,肺炎克雷伯氏菌（Klebsiella pneumoniae）对TPhT具有良好的吸附降解效果.0.3-3.0 g·L^-1菌体在2.0 h内对3 mg·L^-1TPhT的吸附率均超过70%,最高达97.9%;5 d内对TPhT的降解率为26.4%-54.6%;其离体胞内酶2.0 h内对TPhT的降解率也高达28.1%-77.8%.K.pneumoniae对TPhT的降解发生在细胞内,降解速率的增长趋势随时间的延长而变缓,胞内酶在细胞体外对TPhT的降解在2.0 h时达最大值,完整细胞在第1 d对TPhT的降解速率最快,而第2-5 d的变化趋势较平稳.菌体对TPhT的吸附降解过程包括了TPhT的细胞表面吸附、体内外双向运输和体内降解过程.其中,表面吸附的TPhT含量随时间的增长呈现线性增加的趋势;细胞内部的TPhT含量在前3 d快速下降,从55.9%降至17.0%,之后则趋于稳定;上清液中的TPhT含量变化趋势则与细胞内部的相反.

The biosorption and hiodegradation of triphenyltin （TPhT） from aqueous solutions by isolated strains were investigated through microbial separation and characteristic studies. The results illuminated that Klebsiella pneumoniae was an effective strain for the biosorption and removal of TPhT. 70 % to 97.9 % of TPhT with initial concentration of 3 mg·L^-1 could be absorbed within 2 h, and 26.4 % to 54.6 % of this TPhT was biodegraded within 5 d using 0.3 g·L^-1 to 3.0 g·L^-1 biomass of K. pneumoniae. TPhT could be more effectively degraded by separated endoenzyme than by cell biomass, and 28.1% to 77.8 % of TPhT would be degraded by this way within 2.0 h. The biodegradation experiments also showed that the degradation of TPhT by K. pneumoniae mainly occurred intracellularly and the increase of degradation rate gradually slowed down with time. Separated endoenzyme gave rise to the highest biodegradation of TPhT at the contact time of 2.0 h, while the intact cell achieved the highest rate of biodegradation within 1 d, and then reached a plateau among 2 d to 5 d. The experiments also revealed that the biodegradation process of TPhT included biosorption by cell wall, active transportation across cell membrane, and biodegradation within cytoplasm, in which TPhT bio-adsorbed on the cell wall increased linearly with time, TPhT inside the cell wall decreased rapidly from 55.9 % to 17.0% during the first 3 d, and then turned to smooth;while TPhT in the supernate changed reversely with that occurred inside the cell wall.