Construction and characterization of fermentative lactate dehydrogenase Escherichia coli mutant and its potential for bacterial hydrogen production

In Escherichia coli, classified as a mixed-acid producer in fermentation, D -lactate is one of the final metabolites from pyruvate. In order to achieve a high efficiency of bacterial hydrogen production from glucose, we have c onstructed an E. coli strain deficient in fermentative lactate dehydrogenas e (LDH-A) by P1 transduction. The mutant, designated as MC13-4, entirely lo st LDH-A activity while retaining whole formate hydrogenlyase activity. Thi s mutation resulted in an increase in hydrogen production based on glucose consumed. The effect of uptake hydrogenases on the hydrogen production was also discussed.