Cellulosic ethanol production by Zymomonas mobilis harboring an endoglucanase gene from Enterobacter cloacae.
Enterobactercloacae was isolated from the gut of the wood feeding termite, Heterotermes indicola, and a 2.25-kb fragment conferring cellulase activity was cloned in Escherichia coli. The cloned fragment contained a 1083-bp ORF which could encode a protein belonging to glycosyl hydrolase family 8. The cellulase gene was introduced into Zymomonas mobilis strain Microbial Type Culture Collection centre (MTCC) on a plasmid and 0.134 filter paper activity unit (FPU)/ml units of cellulase activity was observed with the recombinant bacterium. Using carboxymethyl cellulose and 4% NaOH pretreated bagasse as substrates, the recombinant strain produced 5.5% and 4% (V/V) ethanol respectively, which was threefold higher than the amount obtained with the original E.cloacae isolate. The recombinant Z. mobilis strain could be improved further by simultaneous expression of cellulase cocktails before utilizing it for industrial level ethanol production.
Department of Biotechnology, Anna University Tiruchirappalli, Tiruchirappalli 620024, Tamil Nadu, India.
P Thirumalai
PT
Vasan
P Sobana
PS
Piriya
D Immanual Gilwax
DI
Prabhu
S John
SJ
Vennison
D000818:Animals; D002480:Cellulase / Q000235:genetics / Q000378:metabolism*; D002482:Cellulose / Q000378:metabolism*; D003001:Cloning, Molecular; D016972:Enterobacter cloacae / Q000201:enzymology* / Q000235:genetics; D000431:Ethanol / Q000378:metabolism*; D024861:Genetic Enhancement / Q000379:methods*; D020049:Isoptera / Q000382:microbiology*; D011994:Recombinant Proteins / Q000378:metabolism; D017355:Zymomonas / Q000235:genetics / Q000378:metabolism*
D011994:Recombinant Proteins; D000431:Ethanol; D002482:Cellulose; D002480:Cellulase