%0 Journal Article
%T New Lipase for Biodiesel Production: Partial Purification and Characterization of LipSB 25-4
%A Aysel Ugur
%A Nurdan Sarac
%A Rukiye Boran
%A Berk Ayaz
%A Ozgur Ceylan
%A Gulten Okmen
%J ISRN Biochemistry
%D 2014
%R 10.1155/2014/289749
%X The lipolytic activities of 300 Streptomyces isolates were determined in Tributyrin and Rhodamine-B Agar. Lipase activities were also measured with p-nitrophenyl palmitate (p-NPP) as a substrate. The strain of Streptomyces bambergiensis OC 25-4 used in this study was selected among 300 strains of Streptomyces from MUCC as the best lipase producer. The incubation conditions were optimized and the inoculum amount, incubation period, effect of carbon and nitrogen sources, and rates of MgSO4 and CaCO3 were investigated. LipSB 25-4 (the lipase produced by S. bambergiensis OC 25-4 strain) was partially purified with ammonium sulphate precipitation, dialysis, and gel filtration chromatography 2.73-fold and with 92.12£¿U/mg specific activity. The optimal pH and temperature for LipSB 25-4 were determined as 8.0 and 50¡ãC, respectively. The lipase has high stability in all pH and temperature values used in this study. While LipSB 25-4 was slightly activated in the presence of ¦Â-mercaptoethanol, it was slightly reduced by PMSF. The enzyme conserved approximately 75% of its activity at the end of 60£¿h, in the presence of methanol and ethanol. Since LipSB 25-4 displays high activity in the thermophilic conditions and stability in the presence of organic solvents, this lipase can catalyse the biodiesel production from olive oil by the transesterification reactions. 1. Introduction The increasing severity of the global energy crisis, shortage of fossil fuels, increase in the crude oil prices, and an increasing number of environmental problems and environmental concerns to reduce pollution have resulted in the rapid growth of research into alternative energy sources, as well as the use of such sources [1, 2]. Biodiesel which is derived from triglycerides by transesterification with methanol is receiving increasing attention as an alternative, nontoxic, biodegradable, and renewable source of fuel and energy with significantly lower exhaust emissions of particulate matter and green-house gases [3¨C5] and for its ability to replace fossil fuels. Chemically, biodiesel is produced by transforming triglycerides into fatty acid alkyl esters in the presence of alcohol, such as methanol or ethanol, and an acid or alkali catalyst, generating glycerol as a by-product [6]. Enzymes represent an environmentally friendly alternative to chemical catalysts [7]. Utilization of lipase as a catalyst for biodiesel fuel production has great potential compared with chemical methods [7, 8]. Recently, lipase-catalyzed methanolysis method has become more attractive than the traditional chemical
%U http://www.hindawi.com/journals/isrn.biochemistry/2014/289749/