초록
With the aim of isolating a biocatalyst able to catalyze biodiesel production from microbial source, Ralstonia sp. CS274 was isolated and a lipase from the strain (RL74) was purified. Molecular weight of RL74 was estimated to be 28,000Da by SDS-PAGE. The activity was highest at 50-55<SUP>o</SUP>C and pH 8.0-9.5 and was stable at pH 7.0-12.0 and up to 45<SUP>o</SUP>C. It was resistant to oxidizing and reducing agents and the activity was enhanced by detergents. RL74 was 1,3 specific and K<SUB>m</SUB> and V<SUB>max</SUB> for p-nitrophenyl palmitate were 2.73+/-0.6mM and 101.4+/-1.9mM/minmg, respectively. N-terminal amino acid sequence showed partial homology with that of Penicillium lipases. RL74 produced biodiesel more efficiently in palm oil than in soybean oil; and the production was highest at pH 8.0, at 5% methanol and at 20% water content.