Isolation and characterization of lipid-degrading Bacillus thermoleovoransIHI-91 from an icelandic hot spring

An efficient lipid-degrading thermophilic aerobic bacterium was isolated fr om an icelandic hot spring and classified as Bacillus thermoleovorans IHI-9 1. The aerobic bacterium grows optimally at 65 degreesC and pH 6.0 and secr etes a high level of lipase (300Ul(-1)). The newly isolated strain utilizes several lipids such as palmitic acid, stearic acid, lanolin, olive oil, su nflower seed oil, soya oil, and fish oil as sole carbon and energy source w ithout an additional supply of growth factors. The degradation of about 93 % of triolein, which is present in olive oil, was observed after only 7h of fermentation at a maximal growth rate of 1.0 h(-1). During growth at optim al conditions on yeast extract, the doubling time was only 15 min. Based on 168 rDNA studies, DNA-DNA hybridization and morphological and physiologica l properties, the isolate IHI-91 was identified as Bacillus thermoleovorans IHI-91 sp. nov. Because of its production of high concentrations of thermo active lipases and esterases and the capability pf degrading a wide range o f lipids at high temperatures, the isolated strain is an ideal candidate fo r application in various biotechnological processes such as wastewater trea tment.