Comparative fermentation performance and HPLC volatile profiling of Saccharomyces strains utilizing fruit and vegetable processing waste for bioethanol production

Abstract

The food manufacturing sector generates substantial quantities of pulp waste, thereby creating environmental and economic issues. The valorization of such bio-waste into value-added products represents a reasonable pathway for circular economy and matches the UN Sustainable Development Goals. This work investigates the potential for bioethanol from four different fruit and vegetable waste streams—litchi, peach, orange, and carrot—sourced from Himalayan Food Park, Kashipur, Uttarakhand, India. Two commercial yeast strains 71B (Saccharomyces cerevisiae) and UVafermBC (S. bayanus) were analyzed under same fermentation conditions. The progress of fermentation was monitored daily by °Brix measurement. Post-fermentation, ethanol was recovered via rotary vacuum evaporator, and quantitative volatile metabolites viz., ethanol, methanol, and ethyl acetate were carried out using HPLC analysis. All four substrates showed progressive reduction of °Brix indicating active fermentation. Peach pulp gave the highest alcohol by volume (ABV: 16.9–19.9%), while carrot juice gave the lowest values (12.14–14.9%). Strain 71B produced 2.74–2.98% higher ABV and outperformed UVafermBC in fermentation efficiency across all tested substrates. HPLC profile confirmed maximum ethanol in peach-fermented samples (upto 151.6 mg/mL). Notably, strain 71B synthesized substantial ethyl acetate in fruit-based substrates (31.8–162.2 mg/mL), while UVafermBC yielded minimal amounts. Our data affirmed the applicability of agro-industrial waste as a sustainable feedstock for bioethanol and ester synthesis. This study identified Peach pulp and strain 71B as the best substrate–yeast combination, thereby, supporting food-waste valorization, promoting clean energy generation and responsible consumption in accordance with UN-SDG targets.