RESUMO
Abstract Lipases are enzymes of immense industrial relevance, and, therefore, are being intensely investigated. In an attempt to characterize lipases at molecular level from novel sources, a lipase gene from Bacillus amyloliquefaciens PS35 was cloned, heterologously expressed in Escherichia coli DH5α cells and sequenced. It showed up to 98% homology with other lipase sequences in the NCBI database. The recombinant enzyme was then purified from E. coli culture, resulting in a 19.41-fold purification with 9.7% yield. It displayed a preference for long-chain para-nitrophenyl esters, a characteristic that is typical of true lipases. Its optimum pH and temperature were determined to be 8.0 and 40 °C, respectively. The half-lives were 2.0, 1.0 and 0.5 h at 50 °C, 60 °C and 70 °C, respectively. The metal ions K+ and Fe3+ enhanced the enzyme activity. The enzyme displayed substantial residual activity in the presence of various tested chemical modifiers, and interestingly, the organic solvents, such as n-hexane and toluene, also favored the enzyme activity. Thus, this study involves characterization of B. amyloliquefaciens lipase at molecular level. The key outcomes are novelty of the bacterial source and purification of the enzyme with desirable properties for industrial applications.
Assuntos
Adulto , Feminino , Humanos , Masculino , Dieta/psicologia , Planejamento Ambiental , Abastecimento de Alimentos/métodos , Obesidade/epidemiologia , Características de Residência/estatística & dados numéricos , Índice de Massa Corporal , Bebidas/estatística & dados numéricos , Comércio , Dieta/etnologia , Dieta/estatística & dados numéricos , Ingestão de Energia , Fast Foods , Frutas , Abastecimento de Alimentos/estatística & dados numéricos , Inquéritos Epidemiológicos , Los Angeles/epidemiologia , Atividade Motora , Obesidade/prevenção & controle , Fatores Socioeconômicos , Inquéritos e Questionários , Comportamento Sedentário/etnologia , Edulcorantes/administração & dosagem , Verduras , Caminhada/estatística & dados numéricosRESUMO
Background: lipase is an enzyme with immense application potential. Ester synthesis by lipase catalysis in organic media is an area of key industrial relevance. Enzymatic preparations with traits that cater to the needs of this function are hence being intensely researched
Objective: the objectives of the study were to immobilize the lipase from Bacillus sp. PS35 by cross-linking and adsorption onto styrene-divinyl benzene [Sty-Dvb] hydrophobic resin and to comparatively characterize the free and immobilized lipase preparations. The work also aimed to apply the immobilized lipase for catalysing the fatty acid methyl ester [FAME] synthesis from palm oil and optimize the process parameters for maximizing the yield
Materials and Methods: In this study, the purified lipase from Bacillus sp. PS35 was immobilized by adsorption onto styrene-divinyl benzene hydrophobic resin with gluteraldehyde cross-linking
Results: the immobilized enzyme showed better pH and temperature stabilities than the free lipase. Organic solvent stability was also enhanced, with the relative activity in the presence of methanol being shifted from 53% to 81%, thereby facilitating the enzyme's application in fatty acid methyl ester synthesis. It exhibited remarkable storage stability over a 30-day period and after 20 repetitive uses. Cross-linking also reduced enzyme leakage by 49%. The immobilized lipase was then applied for biodiesel production from palm oil. Methanol and oil molar ratio of 5:1, three step methanol additions, and an incubation temperature of 50[degree]C were established to be the ideal conditions favoring the transesterification reaction, resulting in 97% methyl ester yield
Conclusions: these promising results offer scope for further investigation and process scale up, permitting the enzyme's commercial application in a practically feasible and economically agreeable manner