Study On Enzymatic Production Of Biodiesel By Hydrolysis Of Oil Followed By Esterification

Lipases (triacylglycerol acylhydrolase, EC3.1.1.3) can catylyzehydrolysis, esterification, transesterification, acidolysis, and alcoholysisreaction. Petroleum diesel can be substituted by fatty acid esters(also calledbiodiesel)which can be produced from oil and short chain alcohols. RecentlyBiodiesel have drawn more attention. Biodiesel was synthesized from ricebran oil with low acid value by Candida sp.99-125lipase. Biodiesel wassynthesized by hydrolysis of oil followed by esterification. The results wereas follows:1. The glycerides and fatty acid composition of acidified rice bran oil,crude rice bran oil, refined rice bran oil and waste cooking oil was analyzed.The main difference of oil was from the free fatty acid content.2. The hydrolysis reaction conditions catalyzed by lipase were optimizedby single factor and response surface method. The optimal reaction conditionsare: ratio of water to oil1.2, lipase amount0.3%(mass fraction to oil)and reaction temperature40℃. Hydrolysis degree of90.6%was got in the optimalreaction condition after48h. The components of glycerides weremonoglyceride1.0%, diglyceride3.2%and triglyceride5.2%.3. We study the effect of additive on oil hydrolysis reaction catalyzed bylipase. When2.6%Ca(OH)₂(mass fraction to oil) was added, hydrolysisdegree of93.3%was got after24h. When Ca(OH)₂was added in thehydrolysis reaction,the result with shorter reaction time and higher hydrolysisrate was got at the same time.4. Acid value of oil had an impact on biodiesel conversion rate. Biodieselconversion rate increased with increasing the acid value of oil. Biodieselwhich was produced from rice bran oil with low acid value was synthesizedby hydrolysis of oil followed by esterification. An81.8%biodiesel conversionrate was obtained. A key attribute of the hydrolysis-esterification route is itsability to utilize oil with low acid value.