Extraction using multiple enzymes and lipase-assisted transestirification of Jatropha curcas L. oil for biodiesel

Date

5-2007

Degree

Bachelor of Science in Chemistry

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Veronica P. Migo

Abstract

Production of bio-fuel from plant materials is a major step toward harnessing one of the world's most-prevalent, yet least-utilized renewable energy resources. One of the most promising sources of biodiesel today is the Jatropha curcas L. also known as "Tuba-tuba" in our country. Oil from its seeds is usually extracted by hexane extraction. In this experiment, conventional process, which is hexane extraction, was compared with two enzymatic alternatives in which several enzyme preparations (cellulase, n-amylase, xylanase and protease, specifically bromelain) were used to increase the oil extraction yield: (i) extraction using single enzymes and (ii) extraction by consecutive enzymatic treatment. The effect of various parameters, enzyme concentration, temperature and incubation time on the extraction yield was studied to define the most satisfactory processing conditions. After the oil had been released by the enzyme reaction, it was separated by centrifugation. Using the single enzymatic treatment, results showed that the highest % oil yield was obtained from the bromelain oil extraction with a value of 64.4 s 6.4%, which is almost approximately 80% of the extracted oil from hexane extraction. Upon using the consecutive enzymatic treatment, it was found out that the most appropriate combination was the XACB (xylanase-amylase-cellulase-bromelain) scheme. It was notable to know that by the addition of this proteolytic enzyme (bromelain) with the combined carbohydrates (X, A, C), the yield reached a remarkable % oil yield of 79.46 . 0.02%. This result is relatively comparable with that of the hexane extraction which gave a value of 80.63 t 2.65% oil yield. Furthermore, the use of bromelain alone in oil extraction is capable enough of producing significantly high oil yield. This implies that enzymatic method is a very good alternative for oil extraction. Chemical transesterification, specifically base-catalyzed method was also compared with lipase-assisted method of transesterification. Result from the lipase-assisted transesterification showed a percent ester recovery of 75.75%, which was relatively comparable with that of the base-catalyzed reaction (89.83%). Results from the GC analysis of both esters were relatively comparable, showing that the fatty acid content of the jatropha oil is mostly composed of monounsaturated fatty acid, specifically oleic acid (C18:1). The proposed methods in this experiment could be environmentally and economically important, since these enzymatic methods were proven to be competitive enough with the existing methods of extraction and transesterification. Moreover, this could be a major step towards the creation of an eco-friendly transportation fuel that is relatively clean on combustion.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

LG 993.5 2007 C4 L44

Document Type

Thesis

This document is currently not available here.

Share

COinS