Cell Surface Display Of E.Coli Using Xylan

This paper aims at making E.coli to use xylan as substrate by cell surface displaysystem. In this research, we constructed a vecter pAB firstly, and then fused with blc,β-xylosidase7gene from Fibrobacter succinogenes S85, endoxylanase3gene fromFusarium graminearum, α-arabinofuranosidase gene from Bacillus subtilis168wereco-expressed and displayed on the surface of the E. coli BL21(DE3). The engineeringstrains developed a whole cell biocatalyst capable of utilizing xylan.By Immunofluorescence microscopy and enzyme assay, we can assay thexylanases activities on the cell surface of the engineering strains, and the M3strain isthe best candidate which could absorb more xylan as substrate and can be applied tothe consolidated bioprocessing (CBP). The degradation in vitro of xylan by cellsurface display was the first step in CBP.We explored fermentation optimization about M3strain. And the result showedthat30℃was the optimal temperature and yeast extract help the strain to use morexylan. In order to compare the effect of secretion system with cell surface display,M4and M5were constructed. The result showed that the secretion system did betterthan cell surface display system in the hydrolysis of xylan respect.