Ghaidaa Jihadi Mohammed

Department of Biology/College of Science/University of Al-Qadisiyah, Iraq.

Abstract

Lipases are hydrolytic enzymes which hydrolyse triglycerides to free fatty acids and glycerol. Bacterial lipase producers were isolated from certain loamy arid soils. Eight thermotolerant bacteria able to produce lipases were identified down to their species level. Identification studies have revealed that 5 isolates were belonging to Bacillus stearothermophilus, while the others were belonging to B. megaterium; B. licheniformis and B. subtilis. The impact  of the incubation period ,medium pH, temperature ,  the source of carbon for the lipase production was detected. Results have shown that the optimal conditions for Lipases production by most of these bacteria were incubation temperature of 50°C, incubation period of 72 hours, pH 7.0, presence of 0.1% yeast extract, and when sucrose plus tributyrin were supplied as carbon sources. Production of lipases by the used heat resistant bacteria could be of academic and applied importance especially for manufacture of detergents.

Keywords: Lipase, Thermotolerant bacteria, Loamy arid soils.