Optimization of ethanol production from carob pod extract using immobilized Saccharomyces cerevisiae cells in a stirred tank bioreactor

► Ethanol fermentation was optimized in carob extract using immobilized cells. ► Repeated-batch fermentation was carried out successfully in carob extract. ► Fermentation time was decreased fewer than 12 h after first cycle. ► Ethanol fermentation was performed from non-enrichment carob extract using immobilized cells. ► Immobilized cells were shown to be reusable for five cycles in carob extract.