[Characteristics of biodegradation of triphenyltin by enzyme obtained from Klebsiella pneumoniae].

The objective of this study is to illuminate the mechanism of biodegradation of triphenyltin (TPhT). The removal of TPhT by Klebsiella pneumoniae was, therefore, investigated through characteristics studies. The influences of the various parameters were also discussed. The results demonstrated that the cell, extracellular secretion and intracellular enzyme were the effective biomasses for the biodegradation of TPhT. At initial concentration of 3 mg x L(-1), 10.9%, 5.3% and 47.9% of TPhT could be degraded by these biomasses respectively at 30 degrees C within 2 hours under an rotary shaker at 120 r x min(-1). The experimental results also showed that the enzyme activity could be affected by the buffers, pH, temperature, metals and the concentration of TPhT. The degradation efficiency would reach the highest point at pH 8, and at the optimal temperature of 50 degrees C. Metals including Mg2+, Mn2+, Fe2+ and Fe3+ improved the enzyme activity at certain concentrations. In the presence of 15 mg x L(-1) of Mg2+, the removal percentage of TPhT was up to 73.8%. It suggested that the metals activated the enzyme and interacted with the TPhT enabling its removal during the biodegradation process. Linear plots of removal ratios versus concentrations of TPhT meant that the biodegradation fitted the Michaelis-Menten model. The Vmax and Km of this biodegradation were 0. 15 mg x (L x min)(-1) and 47.1 mg x L(-1), respectively.