Interactions among triphenyltin degradation, phospholipid synthesis and membrane characteristics of Bacillus thuringiensis in the presence of D-malic acid

Degradation pathway and surface biosorption of triphenyltin (TPT) by effective microbes have been investigated in the past. However, unclear interactions among membrane components and TPT binding and transport are still obstacles to understanding TPT biotransformation. To reveal the mechanism involved, the phospholipid expression, membrane potential, cellular mechanism and molecular dynamics between TPT and fatty acids (FAs) during the TPT degradation process in the presence of D-malic acid (DMA) were studied. The results show that the degradation efficiency of 1 mg L-1 wi by Bacillus thuringiensis (1 g L-1) with 0.5 or 1 mg L-1 DMA reached values up to approximately 90% due to the promotion of element metabolism and cellular activity, and the depression of FA synthesis induced by DMA. The addition of DMA caused conversion of more linoleic acid into 10-oxo-12(Z)-octadecenoic acid, increased the membrane permeability, and alleviated the decrease in membrane potential, resulting in TPT transport and degradation. Fluorescence analysis reveals that the endospore of B. thuringiensis could act as an indicator for membrane potential and cellular activities. The current findings are advantageous for acceleration of biosorption, transport and removal of pollutants from natural environments. (C) 2016 Elsevier Ltd. All rights reserved.