Production of dihydroxyacetone from glycerol by engineered Escherichia coli cells co-expressing gldA and nox genes

Glycerol can be converted into more valuable compound dihydroxyacetone by the nicotinamide adenine dinucleotide (NAD+)-dependent glycerol dehydrogenase. However, it is economically prohibitive to produce dihydroxyacetone using purified glycerol dehydrogenase at the expense of a stoichiometric amount of the cofactor NAD + . In this study, Escherichia coli was engineered for dihydroxyacetone production by enhancing its glycerol dehydrogenase activity and introducing NADH oxidase activity. Under optimized conditions, dihydroxyacetone productivity reached 0.13 g/h/g wet cell mass by recombinant E. coli D4 (pET-24b-gldA+nox) cells co-expressing gldA gene from E. coli and nox gene from Enterococcus faecalis . It was interesting to note that exogenous NAD+ greatly improved dihydroxyacetone production for the whole-cell biotransformation process. These results should be useful for the development of advanced bioprocess in terms of glycerol utilization. Keywords : Dihydroxyacetone, Glycerol dehydrogenase, NAD + , whole-cell biotransformation, Escherichia coli African Journal of Biotechnology Vol. 12(27), pp. 4387-4392