Isolation of lipase producing bacteria from fat milk and optimization of various parameter effect on lipase enzyme production in submerge fermentation

Fat milk sample was selected to isolationg lipolitic bacteria. 25 strains were isolated from fat milk. The best isolate was selected for identifing and further study according to lipase producing with amount of 177 U/ml lipase activities that was the most lipase activity among bacteria strains. This bacterium was identified as a strain of genus Bacillus based on morphological and biochemical characterization and 16S rRNA gene sequence. Optimization was done for economical producing of lipase by Respone Surfase Method. After optimization, screening of culture parameters was conducted by Placket Burman Design. The effect of oive oil, yeast extract, peptone, Mgcl2, glucose, corn syrop, molase, sesame oil, black seed oil, rotation speed and sunflower oil was investigated for optimization. The optimum lipase activity (574 U/ml) was achieved at optimum levels of factors of sesame oil (25.0w/w), olive oil concentration (22.5 g/L), yeast extract (10 g/l) and Mgcl2 (25 mM/l) (160 rpm, pH 6.5 and 24 h) that lipase activity increased to 3.24-fold. Kinetic parameters, Km and Vmax for the purified lipase was calculated from the Michaelis–Menten plot. The lipase showed lower Km value (1.62 mM) and high Vmax value (0.667 mM/min) than the other Bacillus subtilis.