A Novel Green Process for Synthesis of 3-Hydroxyalkanoate Methyl Ester Using Lipase and Novel mcl-co-lcl PHA as Catalyst and Substrate

摘要

A new type of medium-chain-length-co-long-chain-length polyhydroxyalkanoate (mcl-co-lcl PHA) containing 39.25 mol 3-hydroxyhexadecanoic (3HHD) was isolated from Bacillus thermoamylovorans strain PHA005 and utilized as biofuel substrate. A novel process to produce 3-hydroxyalkanoate methyl ester (3HAME) using mcl-co-lcl PHA was transesterification via an enzyme-catalysis was used. The optimal conditions for 3HAME productions include enzyme loading of 0.50 g per 3.0 g of substrate, a methanol/PHA ratio of 3:1 (v/w), 0.50 wt of water based on PHA weight, a stirring speed of 150 rpm, a reaction temperature of 45 degrees C and a reaction time of 30 h. The highest methyl ester content of 96.5 was achieved under optimum conditions. In addition, the partial chemical and fuel properties of 3HAME were also investigated. The results found that the properties of 3HAME in this study were similar to 3HAME from chemical catalysts, including other biodiesel, and it meets the standards of international specification (EN 14217 and ASTM D 6751). This is the first report that has assessed the plausibility of producing biofuel from a PHA-containing the 3HHD monomer. Notably, the production of 3HAME via enzyme catalysis has not been previously reported.