Wax synthase MhWS2 from Marinobacter hydrocarbonoclasticus: substrate specificity and biotechnological potential for wax ester production

Wax synthases are involved in the biosynthesis of wax esters, lipids with great industrial potential. Here, we heterologously expressed the native wax synthase MhWS2 from Marinobacter hydrocarbonoclasticus in Saccharomyces cerevisiae and performed comprehensive analysis of its substrate specificity. The enzyme displayed high wax synthase (but no diacylglycerol acyltransferase) activity both in vivo and in vitro. In the presence of exogenous fatty alcohol, wax esters accounted for more than 57% of total yeast lipids. In vitro, MhWS2 produced wax esters with most of the tested substrates, showing the highest activity with 14:0-, 18:1-, 18:0-, 12:0-, and 16:0-CoA together with saturated C10-C16 fatty alcohols. Co-expression with genes encoding fatty acyl reductases resulted in the accumulation of C26-C36 wax esters. Altogether, our results provide a detailed characterization of MhWS2 which should be useful in the development of strategies for producing wax esters in various expression systems.