A novel sono-assisted acid pretreatment of chili post harvest residue for bioethanol production. (August 2016) - Sindhu, Raveendran
Highlights: First report on sono-assisted acid pretreatment of chili post harvest residue. Effectively removed hemicelluloses and lignin. Maximum reducing sugar yield was 0.465 g/g of dry biomass. Hydrolyzate is devoid of fermentation inhibitors like organic acids and furfurals. Fermentation yielded 16.87 g of ethanol with an efficiency of 71.03%. Abstract: The objective of the present study was to develop a sono-assisted acid pretreatment strategy for the effective removal of lignin and hemicelluloses and to improve the sugar yield from chili post harvest residue. Operational parameters that affect the pretreatment efficiency were studied and optimized. Inhibitor analysis of the hydrolyzate revealed that major fermentation inhibitors like furfural, hydroxymethyl furfural and organic acids like citric acid, succinic acid and propionic acid were absent. Changes in structural properties of the biomass were studied in relation to the pretreatment process using scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier Transform Infrared (FTIR) analysis, and the changes in chemical composition was also monitored. The biomass pretreated with the optimized novel method yielded 0.465 g/g of reducing sugars on enzymatic hydrolysis. Fermentation of the non-detoxified hydrolysate yielded 2.14% of bioethanol with a fermentation efficiency of 71.03%.