초록
<P>A genetically-engineered strain of the yeast Candida utilis harboring genes encoding (1) an acetoacetyl-CoA transferase from Clostridium acetobutylicum ATCC 824, (2) an acetoacetate decarboxylase, and (3) a primary-secondary alcohol dehydrogenase derived from Clostridium beijerinckii NRRL B593 produced up to 0.21?g/L of isopropanol. Because the engineered strain accumulated acetate, isopropanol titer was improved to 1.2?g/L under neutralized fermentation conditions. Optimization of isopropanol production was attempted by the overexpression and disruption of several endogenous genes. Simultaneous overexpression of two genes encoding acetyl-CoA synthetase and acetyl-CoA acetyltransferase increased isopropanol titer to 9.5?g/L. Moreover, in fed-batch cultivation, the resultant recombinant strain produced 27.2?g/L of isopropanol from glucose with a yield of 41.5?% (mol/mol). This is the first demonstration of the production of isopropanol by genetically engineered yeast.</P>