Using lipase Candida rugosa as a catalyst for the biodiesel production from Tra fish (Pangasius hypophtalmus) oil

Abstract

In this work, lipase from Candida rugosa (LCR) was used as a catalyst for the transesterification reaction of fish oil with methanol. The research process consists of three stages: determine the material properties and the activity of the enzyme from Candida rugosa, transeter of fish oil with methanol catalyzed by the enzyme lipase, evaluation indicators of the quality of biodiesel obtained. Fish oil contains 62% unsaturated fatty acid, acid value of 2.2 mg KOH/g. Activity and specific activity of enzyme were respectively 1064 U/mg enzyme and 2782 U/mg protein. Factors affecting the efficiency of conversion of fatty acid methyl esters - FAME were investigated: the molar ratio of methanol/fish oil, ratio of enzyme/fish oil, temperature reaction, pH reaction, concentration of buffer and reaction time. Yield of biodiesel conversion was 92.65% with optimal conditions: rate of methanol/fish oil was 4:1, the ratio of enzyme/substract was 2%, reaction temperature was 40°C, additional 10% buffer solution pH 7 with 96 hour response time. Products biodiesel obtained FAME components accounted for 98.94%; density at 15°C is 0.8816 g/ml; no free water and glycerine, consistent with the original standard biodiesel (B100) (TCVN 7717:2007). However, the acid value of 1.7 mg KOH products/g higher than the allowable value.