earticle

영어

Recently, polylactic acid (PLA), a biodegradable polymer showing many valuable characteristics and friendly environment, has been widely used in industrial applications. Lactide formation from lactic acid has played crucial role on the PLA formation. Candida antarctica lipase B (CALB) with high enantioselectivity toward R-form of substrate was found to catalyze the lactide formation. However, the abundant source of S-lactic acid commercially produced through microbial fermentation of glucose was rarely catalyzed by CALB wild type. By using Autodock program, 2 amino acid residues Tryp104 and Thr138 on CALB displaying the key role on the enantioselectivity of CALB favouring R-form of alkyl lactate were found. CALB mutants from these sites were made and transformed successfully into Pichia pastoris X33. We are expected that these mutants will show the enantioselectivity toward S- form of lactide production.