The increasing demand for renewable energy has driven research into bioethanol production. This study explores the use of immobilized Meyerozyma guilliermondii yeast and co-cultivation with Zea mays (sweet maize) to enhance bioethanol yields. Optimal conditions for yeast adhesion to alginate beads and co-cultivation effects on ethanol production were investigated. Variables such as alginate concentration, bead size, temperature, pH, and nutrients were adjusted to maximize yeast viability and sugar availability. Co-cultivation demonstrated synergistic benefits, significantly improving bioethanol output compared to traditional methods. This approach offers sustainable, efficient bioethanol production with promising environmental and economic advantages.

By employing immobilized Saccharomyces cerevisiae yeast to optimize the enzymatic scarification and fermentation processes, this work seeks to close this research gap and manufacture bioethanol from rice straw. In this work, bioethanol is produced from rice straw by enzymatic scarification and fermentation using immobilized Saccharomyces cerevisiae yeast. In Iraq, where rice is widely grown and rice straw provides lignocellulosic biomass for biofuel, the study was carried out.Pretreatment was the first step in the process, while ethanol recovery was the last. To liberate cellulose and hemicellulose, rice straw was mechanically and chemically processed. Reducing sugars were liberated from preprocessed biomass through enzymatic hydrolysis employing cellulose and hemicellulose enzymes. After being captured and rendered immobile in calcium alginate beads, S. cerevisiae yeast cells retained more than 95% of their vitality. When immobilized yeast was used in the fermentation process, more ethanol was produced than when it wasn't. Peak ethanol concentrations of 25 g/L were achieved after 96 hours thanks to process modifications. 95% of the crude ethanol was purified by distillation. With a 94% efficiency rate, 48 grams of ethanol were produced per liter. Numerous parameters were used to assess the processes of scarification, fermentation, and ethanol generation. Enzymatic hydrolysis was enhanced by the pretreatment mixture and sugar release kinetics. The strength of alginate entrapment was demonstrated by the stability and vitality of immobilized cells. The ethanol content and purity of the product were confirmed by HPLC analysis. According to this study, bioethanol may be produced in Iraq using immobilized yeast and rice straw. Programs for renewable energy and agricultural waste management may be implemented. This technology could become a sustainable fuel if it is developed and made available to the public. The study demonstrates how to optimize scarification and fermentation processes for the conversion of lignocellulosic biomass.