A novel crude glycerol assisted surfactant pretreatment strategy of chili post-harvest residue for bioethanol production

A novel crude glycerol assisted surfactant pretreatment was evaluated for bioethanol production from chili postharvest residue. Among the various surfactants screened crude glycerol assisted polyethylene glycol (PEG) pretreatment was found to be more effective. Various process parameters affecting pretreatment were optimized. The optimum conditions of pretreatment were crude glycerol concentration of 0.55% w/ w, PEG concentration of 4.5% w/ w, biomass loading of 25% w/ w and incubation time of 60 min. Under optimized conditions 0.459 g of reducing sugar per g of dry biomass (g/ g) was observed. The hydrolyzate is devoid of major fermentation inhibitors like furfurals, 5-hydroxymethylfurfural and organic acids like citric acid, succinic acid and propionic acid. Fermentation of the non-detoxified hydrolyzate yielded 8.60 g of bioethanol per 100 g of dry biomass with a fermentation efficiency of 36.68%.