Combining C6 and C5 sugar metabolism for enhancing microbial bioconversion.

Mixed sugars, which are often obtained from renewable biomass, can be converted into biofuels and chemicals by microbial conversion. This sustainable production process can also mitigate man-made climate change when used to petroleum-based fuel and chemical production. In contrast to single sugar fermentations, such as corn-based or sugarcane-based ethanol fermentations, mixed sugar fermentations present significant challenges for cost-effective production of the target products. In particular, inefficient and slow microbial fermentation of non-glucose sugars, such as galactose and xylose from the depolymerization of marine and terrestrial biomass has been a major obstacle. Nonetheless, simultaneous utilization of mixed sugars has recently been demonstrated through innovative metabolic engineering strategies and the discovery of transporters, and metabolic pathways which are necessary for co-fermenting glucose and non-glucose sugars.