Adaptation of Anoxybacillus flavithermus ssp．Yunnanesis E13T to toluene at the level of fatty acid composition of membrane

Abstract:

Abstract:［Objective］ Anoxybacillus flavithermus subsp．yunnanensis is now the only species of thermophilic bacteria able to tolerate toxic solvents at high temperature．The adaptive responses of A．flavithermus subsp． yunnanensis E13T to toluene on the level of fatty acid composition of membrane were studied in detail．［Methods］The extraction of fatty acids was performed according to the method described in the Sherlock Microbial Identification System manual．The fatty acid compositions were analyzed by gas chromatography mass spectrometry (GC-MS)．［Results］In presence of 0.3% (V/V) toluene，key moment to adapt the saturated straight-chain fatty acids was that when cells grew from the lag phase to the initial growth phase in liquid． The saturated straight-chain fatty acids were continuously decreased as the strain E13T to grow．In survival of the cells in 100% toluene，the saturated straight-chain fatty acids increased significantly.［Conclusion］A．flavithermus ssp． yunnanesis E13T alters its membrane fluidity via fatty acid composition to become more rigid when it is exposed to solvent，which is consistent that commonly found in mesophilic organic solvent-tolerant bacteria． However，it adapted its membrane by increasing straight-chain saturated fatty acids，rather than unsaturated fatty acids，which was demonstrated in mesophilic organic solvent-tolerant bacteria．