Enhanced Ethanol Production from Pomelo Peel Waste by Integrated Hydrothermal Treatment, Multienzyme Formulation, and Fed-Batch Operation

Pomelo peel is an abundant pectin-rich biomass waste in China and has the potential to serve as a source of fuels and chemicals. This study reports a promising way to deal with pomelo peel waste and to utilize it as raw material for ethanol production via simultaneous saccharification and fermentation (SSF). An integrated strategy, incorporating hydrothermal treatment, multienzyme formulation, and fed-batch operation, was further developed to enhance the ethanol production. The results show that hydrothermal treatment (120 °C, 15 min) could significantly reduce the use of cellulase (from 7 to 3.8 FPU g–1) and pectinase (from 20 to 10 U g–1). A multienzyme complex, which consists of cellulase, pectinase, β-glucosidase, and xylanase, was also proven to be effective to improve the hydrolysis of pretreated pomelo peel, leading to higher concentrations of fermentative sugars (36 vs 14 g L–1) and galacturonic acid (23 vs 9 g L–1) than those with the use of a single enzyme. Furthermore, to increase the final eth...