Utilization of Agro Based Residue Solid Waste for Production of Lipase-Mediated Synthesis of Isoamyl Butyrate

摘要

Agro-based solid residues are generally considered the best substrate for solid-state fermentation (SSF) hold tremendous potential for the biodiversity. It ca be of special interest. In those processes where the crude fermented product may be used directly as the enzyme source. In addition to the conventional applications in the food and fermentation industries, microbial enzyme have attained significant role in biotransformation involving organic solvent media mainly for lipase-mediated synthesis of esters, focus is being made in this text on isoamyl butyrate synthesis. Lipases (Triacylglycerol acyl ester hydrolases, EC.3.1.1.3) that catalyze the hydrolysis of fats and oils to glycerol and fatty acids, also display catalytic activity towards esterification and interesterification reactions such as ester exchange, acidolysis and alcoholysis of triglycerides. Lipases, particularly those produced by microorganism, have recently become the focus of interest because of their high potential for many industrial applications. The extra cellular lipases were microbially produced and their esterification activity in the synthesis of isoamyl butyrate has been investigated. The lipases were produced from Candida cylindracea 1908 strains using rice bran as solid substrate by solid-state fermentation. The optimum temperature and incubation time for lipase production were found to be 30°C and 72 hrs respectively. Production of lipases was substantially enhanced when the additional carbon sources and nitrogen sources were added. Maltose and malt extract were found to be the best source of additional carbon and nitrogen respectively, giving maximum lipase yield. Isoamyl butyrate, an important fruity flavour ester was synthesized using Candida cylindracea1908 by esterification of isoamyl alcohol and butyric acid. The effects of a various reaction parameters such as pH, incubation temperature, incubation time, substrate (butyric acid and isoamyl alcohol) concentration and effect of various organic solvents has been investigated. The esterification activity was found to be optimum at 25°C at pH 6.5 for 20 hours in both n-hexane with molecular sieves and only in n-hexane. The percentage conversion shows maximum in butyric acid (0.1M) and isoamyl alcohol (0.12M) in both n-hexane with molecular sieves and only in n-hexane. n-hexane shows the better solvent with maximum conversion of 68.5%.