Bioethanol production from fruit waste using a microbial co‐culture of  <i>Bacillus siamensis</i> <scp>F2</scp> and <i>Candida albicans</i> <scp>GP1</scp>

Abstract This study explores the sustainable valorization of fruit waste (FW) for bioethanol production using a consolidated bioprocess (CBP) that combines fermentation and enzymatic hydrolysis in a single step. A co‐culture of Bacillus siamensis F2 (a multienzyme producer) and Candida albicans GP1 (a fermentative yeast) was employed to maximize bioethanol yield. Initially, C. albicans GP1 was isolated and characterized from grape pomace, with its fermentative efficiency tested on various sugars (glucose, sucrose, fructose, cellulose, pectin, and starch). Following this, critical parameters – pH, temperature, fermentation time, substrate concentration, and inoculum levels – were optimized using response surface methodology (RSM) to improve bioethanol production. Under optimal conditions (15% FW concentration, 7.5% v v −1 B. siamensis F2, 8% v v −1 C. albicans GP1, 120 h fermentation time, 35 °C, and pH 7), a maximum bioethanol yield of 48 g L −1 and 0.7 g g −1 of utilized FW was achieved. Techno‐economic analysis revealed positive profitability, indicating the economic feasibility of the process. The successful utilization of FW for bioethanol production highlights its potential as a sustainable solution for waste valorization and renewable energy generation.