Integrated consolidated bioprocessing for simultaneous production of Omega-3 fatty acids and bioethanol

Lignocellulosic biomass represents a promising feedstock for supplying biofuels and other useful bioproducts in near future. As an example of process innovation, this study describes an integrated microbial fermentation process involving a thermoanaerobe and a marine thraustochytrid, aiming at the co-production of docosahexaenoic acids and bioethanol from rice straw biomass as substrate. Key points of the process are: (a) consolidated bioprocessing of pretreated rice straw biomass to bioethanol (anaerobic fermentation) resulting into 1.8 g L−1 bioethanol and 29.40% solubilization of rice straw biomass; (b) utilization of spent lignocellulose derived sugars in microalgal fermentation (aerobic fermentation) with subsequent promising cell growth (2.77 g L−1), substantial lipids (17.05%) and docosahexaenoic acids production (44.0% of total fatty acids). Other major fatty acids (as total fatty acid %) were palmitic acid (13.95%), stearic acid (5.07%), eicosapentaenoic acid (7.24%), and docosapentaenoic acid (16.12%). This study provides a new route for marine algae utilization of lignocellulosic biomass for co-production of bioethanol and value-added bioproducts.