Catalytic Hydrolysis of Fruit Waste Using Magnetic Carbon Acid Catalyst for Bioethanol Production

Abstract

The synthesized magnetic carbon acid catalyst was found promising to replace the homogeneous catalyst in biomass hydrolysis. The as-prepared magnetic carbon acid catalyst contains –COOH, –OH, and –SO3H groups were of importance in the hydrolysis of pomegranate peel waste (Punica granatum). Preliminary experimental results revealing that the temperature, reaction time and catalyst dosage have a great influence on biomass hydrolysis. By optimizing these parameters, 58% of TRS yield was achieved at 140 °C for 2 h reaction time in water medium with the addition of 150 mg of catalyst dosage. The magnetic carbon acid catalyst was regenerated by external magnetic field from the reaction system and reused for up to three consecutive runs with minor loss in activity. Due to some loss of catalyst, the activity of regenerated catalyst in hydrolysis results in reduction of total reducing sugar yield. The hydrolysate from catalytic hydrolysis was fermented into bioethanol with 71.1% of theoretical ethanol yield using baker’s yeast (Saccharomyces cerevisiae). Moreover, the mechanism involved in biomass hydrolysis over prepared catalyst was also studied. The synthesized catalyst provides a novel strategy for converting renewable carbon sources into fermentable sugar.