title: Production of milk-clotting protease from Bacillus subtilis.
abstract: An indigenous Bacillus subtilis strain isolated from soil was found to be a potent milk-clotting protease (mcp) producer. Production optimized using response surface methodology (RSM) yielded 1,190 U/ml of enzyme in medium containing 6% fructose, 1% casein, 0.3% NH4NO3, 10 mM CaCl2, pH 6.0 and inoculated with 3% inoculum and incubated at 250 rpm for 72 h. Solid-state fermentation resulted in 1,080 and 952.3 U/gds of milk-clotting protease using soybean meal and rice bran, respectively, with higher proteolytic values of 18.97 and 9.1 IU/gds. Production in a biphasic system using an overlay of RSM-optimized medium on solid layer of 6% fructose and 1% casein with 1.5% agar resulted in significant enzyme production. Maximum mcp was obtained using a biphasic system where solid: liquid ratio of 3.0 resulted in a final yield of 1,276.65 U/ml with a yield index of 1.80 as compared to static liquid culture. However, significant increase or difference was noted as compared to yield obtained after RSM. This is the first report on the use of RSM for production of mcp from a bacterial species.
authors.affiliation: Department of Microbiology, University of Delhi South Campus, Benito Juarez Road, New Delhi 110021, India.
authors.forename: Kakoli
authors.initials: K
authors.lastname: Dutt
authors.forename: Pritesh
authors.initials: P
authors.lastname: Gupta
authors.forename: Saurabh
authors.initials: S
authors.lastname: Saran
authors.forename: Swati
authors.initials: S
authors.lastname: Misra
authors.forename: Rajendra Kumar
authors.initials: RK
authors.lastname: Saxena
mesh_terms: D000818:Animals; D001412:Bacillus subtilis / Q000201:enzymology* / Q000378:metabolism; D001426:Bacterial Proteins / Q000096:biosynthesis*; D019149:Bioreactors; D005285:Fermentation; D008892:Milk / Q000382:microbiology; D010447:Peptide Hydrolases / Q000096:biosynthesis*; D044367:Phase Transition
chemical_list: D001426:Bacterial Proteins; D010447:Peptide Hydrolases