Innovative strategies for integrating lignocellulosic biomass and microalgae to produce sustainable bioethanol

This study investigated the potential of integrating Parachlorella kessleri biomass with corn stover and tree bark residues as a method for producing bioethanol. The aim was to reduce greenhouse gas emissions, promote environmental sustainability while improving as well food security. The saccharification process involved biomass decrystallization and posthydrolysis, demonstrating the potential use of residual biomass from forests and agriculture. Posthydrolysis resulted in an increase in total reducing sugars in both bark and corn stover. An optimal balance was established to maximize the release of fermentable sugars while minimizing the presence of inhibitors, identifying key factors such as posthydrolysis time for bark and corn stover, the lack of a need for microalgae decrystallization, biomass and microalgae concentration, and the ideal integration point of microalgae in lignocellulosic bioethanol production. Bioethanol production was performed through fermentation assays using Saccharomyces cerevisiae yeast. Despite the higher lignin content of bark, combining it with microalgae provided a higher ethanol yield (33%) than combining microalgae with corn stover (29%). This study is the first to investigate integrating lignocellulosic feedstock and algae biomass in a single bioethanol production system to improve the feasibility of producing advanced renewable biofuels in biorefineries.