초록
<P><B>Abstract</B></P> <P>1,3-Propanediol (1,3-PDO) production from crude glycerol, a byproduct from biodiesel manufacturing, by <I>Clostridium beijerinckii</I> DSM 791 was studied with corn steep liquor as an inexpensive nitrogen source replacing yeast extract in the fermentation medium. A stable, long-term 1,3-PDO production from glycerol was demonstrated with cells immobilized in a fibrous bed bioreactor operated in a repeated batch mode, which partially circumvented the 1,3-PDO inhibition problem. The strain was then engineered to overexpress <I>Escherichia coli gldA</I> encoding glycerol dehydrogenase (GDH) and <I>dhaKLM</I> encoding dihydroxyacetone kinase (DHAK), which increased 1,3-PDO productivity by 26.8–37.5% compared to the wild type, because of greatly increased specific growth rate (0.25–0.40h<SUP>−1</SUP> vs. 0.13–0.20h<SUP>−1</SUP> for the wild type). The engineered strain gave a high 1,3-PDO titer (26.1g/L), yield (0.55g/g) and productivity (0.99g/L·h) in fed-batch fermentation. Overexpressing GDH and DHAK was thus effective in increasing 1,3-PDO production from glycerol.</P> <P><B>Highlights</B></P> <P> <UL> <LI> <I>C. beijerinckii</I> DSM 791 is a robust organism for 1,3-PDO production from glycerol. </LI> <LI> Replacing yeast extract with corn steep liquor increased cell growth and productivity. </LI> <LI> Stable, long-term 1,3-PDO production was obtained in repeated batch fermentations. </LI> <LI> Cell was engineered to overexpress GDH and DHAK. </LI> <LI> 1,3-PDO productivity increased 26.8–37.5% with a greatly increased growth rate. </LI> </UL> </P>