Isolation of a thermophilic bacterium and analysis of its extracellular poly-meric substance

Abstract:

A thermophilic bacterial strain MS-1 was isolated from the water let from an oil well, and identified as Bacillus sp. by its 16S rDNA sequence and morphological characteristics. The bacterium was able to grow at 60℃ and produce extracellular polymeric substance (EPS). Analysis of the EPS showed that there was 48.3%~54.5% polysaccharide, which was composed of mannose:glucose:galactose at a ratio of 2.04︰1.00︰0.89. The protein fraction was 37.2%~42.4% in EPS, containing methionine, leucine, aspartic acid, alanine, histidine and serine.Transmission Electron Microscopy and Environmental Scanning Electron Microscopy were used to observe the extracellular polymeric substances. The strain is useful in microbial profile modification in high temperature oil fields.

Key words:high temperature; Bacillus sp.; extracellular polymeric substances; microbial profile modification