An alkalophilic thermostable lipase produced by a new isolate of Bacillus alcalophilus

An extremophilic bacterium, isolated from mangrove detritus, produced an extracellular alkaline-thermostable lipase. The bacterium was identified on the basis of cell morphology, growth characteristics, G + C molar ratio and DNA/DNA hybridization as a strain of Bacillus alcalophilus. The bacterium grew optimally at pH 10.6, 60 degrees C with NaCl tolerance up to 7.5% (w/v). Carbonates and/or bicarbonates enhanced lipase production, while NaCl had an inhibitory effect. Maximum lipase activity was at 60 degrees C at pH 10.6, with approx. 60% of its activity being retained at 80 degrees C after 20 min and 80% of its activity was retained at pH 11 after incubation at 60 degrees C. A partially purified lipase had similar stabilities to the crude enzyme.