Highly efficient extraction and lipase-catalyzed transesterification of triglycerides from Chlorella sp. KR-1 for production of biodiesel

Abstract

We developed a method for the highly efficient lipid extraction and lipase-catalyzed transesterification of triglyceride from Chlorella sp. KR-1 using dimethyl carbonate (DMC). Almost all of the total lipids, approximately 38.9% (w/w) of microalgae dry weight, were extracted from the dried microalgae biomass using a DMC and methanol mixture (7:3 (v/v)). The extracted triglycerides were transesterified into fatty acid methyl esters (FAMEs) using Novozyme 435 as the biocatalyst in DMC. Herein, DMC was used as the reaction medium and acyl acceptor. The reaction conditions were optimized and the FAMEs yield was 293.82 mg FAMEs/g biomass in 6 h of reaction time at 60 °C in the presence of 0.2% (v/v) water. Novozyme 435 was reused more than ten times while maintaining relative FAMEs conversion that was greater than 90% of the initial FAMEs conversion.

Keywords: Chlorella sp. KR-1; Dimethyl carbonate; Fatty acid methyl esters; Microalgae; Novozyme 435.