Cloning of the Lactococcus lactis adhEGene, Encoding a Multifunctional Alcohol Dehydrogenase, by Complementation of a Fermentative Mutant of Escherichia coli

摘要

The Lactococcus lactis adhE gene, which encodes a multifunctional alcohol dehydrogenase, has been cloned and characterized. A DNA fragment encoding the putative alcohol dehydrogenase domain of the AdhE protein was cloned by screening anL. lactis genomic library in a fermentative mutant ofEscherichia coli and selecting for the ability to grow anaerobically. Further analysis of the clone obtained allowed the cloning of the entire adhE gene sequence. Analysis ofadhE expression in L. lactis during anaerobiosis showed induction at the transcriptional level, especially in medium containing glucose. Constructed mutant strains produced reduced amounts of ethanol under anaerobic conditions. With theL. lactis gene as a probe, adhE homologs were found in other industrially relevant lactic acid bacteria.