Efficient media for high lipase production: one variable at a time approach

Background: lipase enzymes have applications in a wide range of industries. A crucial determining factor of industrial prices of these enzymes is the culture media composition that is constantly under review by researchers. In this work, for maximum lipase production by Bacillus sp. ZR-5, culture media compositions were optimized using "one variable at a time" strategy

Methods: for this purpose, the culture medium parameters such as low and high cost carbon and nitrogen sources, substrates and incubation times were evaluated

Results: maximum lipase activity was achieved after 24 hr of incubation with 1.5% of glucose syrup [1600+/-69.1u/mg], 1% of fish powder [1238+/-36.7 u/mg] and olive oil [1407+/-2.1 u/mg] as low cost carbon and nitrogen sources and substrate, respectively

Conclusion: our results show a significant increase in lipase activity with usage of low cost sources; this could help in reducing the media prices for industrial application of lipase enzyme

Purification and characterization of a thermostable neutrophilic metalloprotease from Pseudomonas sp. DR89

A novel neutrophilic metalloprotease was isolated from Pseudomonas sp. DR.89 isolate which was identified in a mineral spring in Iran. The enzyme was purified from the isolate to 21-folds in a three-step procedure involving ammonium sulfate precipitation, Q-Sepharose ionic exchange and Sephadex G-100 gel filtration chromatography. Resuts showed that the enzyme was active at high temperatures and in a wide-range pH of 5-11 with the optimum of 8.0. The zymogram and sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis revealed the presence of one protease with a molecular weight of 74 kDa. The enzyme activity was decreased by Zn[2+], Mn[2+], H[2]O[2] and Cetyl trimethylammonium bromide [CTAB], whereas its activity was increased by Ca[2+], Mg[2+], Cu[2+] and dimethyl sulfoxide [DMSO]. Na[+], phenylmethyl sulfonylfluoride [PMSF], beta -mercaptoethanol, sodium dodecyl sulfate [SDS], and Triton X-100 did not show a considerable effect on its activity. Casein was a better substrate than bovin serum albumin [BSA] and gelatin for this enzyme. The kinetic parameters [K[m] and V[max]] of the purified protease towards caseinolytic activity were also determined. These properties of the enzyme make it suitable for use in food industries