An alkaline protease producer Bacillus sp. strain CA15 was isolated from soil. The microorganism was found to be closely related to Bacillus cereus based on 16S ribosomal DNA sequencing. The culture conditions for higher protease production were optimized with respect to carbon and nitrogen sources, metal ions, pH and temperature. Maximum protease production was obtained in the medium supplemented with 1% skim milk, 1% starch and 0.6% MgSO 4 .7H 2 O, initial pH 8.0 at 35°C. The best enzyme production was obtained during the stationary phase in which the cell density reached to 1.8x108 cells/mL. The level of protease was found to be low in the presence of inorganic nitrogen sources. The protease production was diminished in the presence of sucrose and lactose. The extreme stability towards Triton X-100, Tween 20 and SDS was observed by Bacillus sp. CA15 alkaline protease. The enzyme activity was inhibited by PMSF suggested that presence of serine residues at the active sites.
An extracellular lipase was produced by Bacillus coagulans by solid-state fermentation. Solid waste from melon was used as the basic nutrient source and was supplemented with olive oil. The highest lipase production (78,069 U/g) was achieved after 24 h of cultivation with 1% olive oil enrichment. Enzyme had an optimal activity at 37 degrees C and pH 7.0, and sodium dodecyl sulfate increased lipase activity. NH4NO3 increased enzyme production, whereas organic nitrogen had no effect. The effect of the type of carbon sources on lipolytic enzyme production was also studied. The best results were obtained with starch and maltose (148,932 and 141,629 U/g, respectively), whereas a rather low enzyme activity was found in cultures grown on glucose and galactose (approx 118,769 and 123,622 U/g, respectively). Enzyme was inhibited with Mn+2 and Ni+2 by 68 and 74%, respectively. By contrast, Ca+2 enhanced enzyme production by 5%.
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