Strain improvement by UV mutagenesis for enhanced lipase production from Bacillus cereus ATA179 strain, nutritional optimization, partial purification of enzyme, characterization and potential in the detergent industry

In this study, Bacillus cereus ATA179 was exposed to UV and total 445 lipase-producing mutants were obtained. The best lipase producing mutant showed the highest enzime activity at 24th hour (10,6 U/ml). The mutant showed a 60% increase in enzyme production and, named as Bacillus cereus EV4. Sucrose (10,8 U/mL) as the best carbon source, (NH4)2HPO4 (15,3 U/mL) as the best nitrogen source, CuSO4 (11 U/mL) as the best metal ion were obtained. EV4 mutant showed a 32% increase in enzyme production in the modified medium created by optimizing nutritional conditions. Optimum temperature and pH of the partially purified enzyme were 60° C and 7.0, respectively. Thermostability studies showed that the enzyme is thermostable. CuSO4, CaCl2, LiSO4, KCl, BaCl2 and Tween 20 had an activating effect on enzyme activity. Vmax and Km kinetic values were found as 17,36 U/mL ve 0,036 mM, respectively. The molecular weight was determined as about 28,2 kDa. The activity enzyme was found to be stable up to 60 days at room temperature, 75 days at + 4ºC and 90 days at -20ºC. The potential strength of the enzyme in the detergent industry was investigated and it was found that the enzyme was not affected by detergent additives; and it was found to be effective in removing fat in fabrics contaminated with oily substances.