Retrofitting analysis of a biorefinery: Integration of 1st and 2nd generation ethanol through organosolv pretreatment of oat husks and fungal cultivation

This study was dedicated to techno-economic analysis of an integrated 1st and 2nd generation biorefinery, where the organosolv pretreated oat husk and thin stillage is valorized through filamentous fungi and baker yeast. By this strategy, process economy can benefit from multiple value-added products including lignin (80% purity), and protein-rich biomass as feed/food ingredients. Ethanol recovery of organosolv pretreatment benefits the already existing equipment in 1st generation ethanol plant. The best results shows that the integration of 10 tons/h oat husk into a process using 18.8 tons/h grains results in increasing ethanol production from 5.2 to 7.5 tons/h, in addition to 1.6 tons/h lignin (80% purity) and 7.6 tons/h fungal biomass. Integrated process is beneficial not only for 2nd but also for 1st generation ethanol production. Selling the fungal biomass as feed and food increased the net present value (NPV) in comparison to conventional ethanol plant by 71% and 7.9-fold, respectively.