Cellobiose utilization in Escherichia coli

Abstract

In nature, there are plenty of energy source that human can use efficiently. In oil palm empty fruit bunch (EFB), there are Lignin (24%~26%), Cellulose (22.5%~25.4%), Hemi-cellulose (24.5%~27.8%) and other components (14%~16%). EFP can be used by biomass source, because of an advantage of price and available quantity. Cellobiose is one of the carbon sources that can be used efficiently because cellulase is expensive, and there are technical limits. Using cellobiose as a carbon source, cell factory is one of the best strategies. In E.coli, some operons that can consume cellobiose are remained as cryptic genes (chb operon, asc operon, bgc operon, bgl operon). To make the strain that can use cellobiose, cryptic operons have to rework by promoter changing. That strain (cp12chb) can use both cellobiose and glucose but show distinct phenotype by catabolite repression. Through understanding of pathway and regulations, strain can be optimized. Gene replacement and deletion by M.A.GE and gene knockout can help understanding the cellobiose utilization.