[Isolation and characteristics of triphenyltin-biosorption and biodegradation strain]

The biosorption and biodegradation 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 x 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 x L(-1) to 3.0 g x 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 oh 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.