Innovative Approaches to Bioethanol Production: Utilizing Olive Oil Wastewater, Milk Whey, and Sugarcane Molasses through Enzymatic Hydrolysis and Yeast Immobilization

Abstract

This work describes a new method for fermentative ethanol production using a triple waste substrate mixture of olive oil wastewater (OOWW), milk whey (MW), and sugarcane molasses (SCM). Enzymatic hydrolysis was performed using a commercial enzyme complex, Natuzyme, at concentrations of 0.25%, 0.5%, and 0.75%. Fermentation was performed at 30 °C, pH 5.5, and 150 rpm using immobilized cells of Saccharomyces cerevisiae (Sc) previously isolated from OOWW. The ethanol yields produced by immobilized S. cerevisiae ranged from 16.56 g/L to a maximum of 34.56 g/L at the 0.5% enzyme concentration, demonstrating an optimal balance between hydrolytic efficiency and yeast activity. Four different fermentation formulations were prepared by varying the proportions of the waste components, resulting in different substrate compositions and fermentation outcomes. These results demonstrate the potential of valorizing heterogeneous waste streams for the sustainable production of ethanol. This study advances environmentally responsible waste management and opens a promising avenue for large-scale ethanol production using yeast immobilization techniques.

Keywords

renewable biofuels / agro-industrial by-products / enzymatic bioconversion / immobilized fermentation / multi-substrate fermentation / sustainable energy

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