LaFaC develops a new integrated process for 1G and 2G ethanol production

Second-generation ethanol (2G ethanol) production from lignocellulosic residues is a topic of great relevance for expanding biofuel production and increasing the energy efficiency of plants. Despite numerous advances in addressing the technological challenges inherent to 2G ethanol production, some important aspects still need to be overcome to implement more robust and feasible processes. These include achieving high ethanol productivities and final concentrations, as well as the complete conversion of biomass-derived sugars into the target product.

To propose solutions to these challenges, and considering its feasibility for industrial application, LaFaC researchers developed a process that integrates first- and second-generation ethanol production. For this purpose, residual molasses from conventional ethanol production was used to increase the sugar load of hydrolysate fractions derived from sugarcane bagasse processing, which served as the culture medium for 2G ethanol production. To enable co-fermentation of pentoses and hexoses, genetically modified strains of Saccharomyces cerevisiae capable of fermenting xylose were employed. Additionally, to increase process productivity and stability, the yeast cells were immobilized and used in a packed-bed bioreactor.

Using the developed process, final ethanol concentrations above 50 g/L and productivities around 22 g/L/h were achieved, with up to 20 recycling cycles of the immobilized cells. These productivity results are higher than those observed in industrial ethanol production plants.

The full results of this study were published in the journal Renewable Energy and can be accessed here.