Improved Glycerol Utilization by Rhodococcus opacus Strain for Renewable Fuels

Glycerol produced from renewable fuel production is an attractive substrate for the production of value-added materials. The engineered Rhodococcus opacus strain MITXM-61 can produce triacylglycerols (TAGs) for biofuels using glucose and xylose. However, it does not produce TAGs on glycerol medium. Anthony J. Sinskey of the Massachusetts Institute of Technology aimed to develop a TAG-producing R. opacus capable of production at high glycerol concentrations.

Adaptive evolution strategy was used to improve the conversion of glycerol to TAGs in MITXM-61. The evolved strain, MITGM-173, grown on glycerol medium produced TAGs at 0.144 g/g of TAG produced per glycerol consumed. MITGM-173 was able to grow on high concentrations of glycerol. The evolved strain was also cultivated in a mixed medium of glycerol, glucose, and xylose and was able to simultaneously consume the mixed substrates and yielded TAGs.

Sinskey's team generated a TAG-producing R. opacus MITGM-173 strain with improved glycerol utilization. Their results showed that the evolved R. opacus strain shows potential in developing a process to generate advanced renewable fuels from mixed sugar feedstocks supplemented with glycerol.