Comparison of Candida tropicalis and Recombinant Escherichia coli BL21 (DE3) Expressed Enzyme Production for Bioconversion of Lignocellulosic Materials

Lignocellulose is the most abundant renewable resource naturally available with great potential for bioconversion to value-added bio-products in this case from coconut husk to reducing sugars with bio-converting enzyme(s) from Candida tropicalis and Escherichia coli BL21(DE3). This study was to colometrically analyze the xylitol bioconversion and PAGE analysis expressed natively and recombinantly. Pretreated coconut husk (PC) and carboxymethylcellulose (CMC) were used as the carbon source in minimal media to monitor the enzymatic activity, reducing sugar and enzyme production. Enzymatic hydrolysis was facilitated through fermentation of different compartments of C. tropicalis and recombinant E.coli BL21(DE3) between 0 to 96 hours. After 2 hour of induction, recombinant E. coli BL21(DE3), 0.224 g/L (IN) showed higher enzymatic activity than C. tropicalis, 0.181 g/L (EX). Bands expressed extracellularly by C. tropicalis had an estimated molecular weight of 45 kDa while recombinant E. coli BL21(DE3) was 7 kDa. Mannitol dehydrogenase had the highest similarity to the expected peptide sequence through MALDI-TOF MS analysis. Recombinant strains are developed to obtain a higher enzymatic activity compare to the native one. Future studies on optimization of production media may be done.