Optimization of calcium, magnesium and zinc ions in yeast nitrogen base media for bioethanol production using response surface method

Safri Ishmayana, Sheila Farahdika, Debora Tamaris Horasio, Agus Safari, Muhammad Fadhlillah, Ukun M.S. Soedjanaatmadja, Retna Putri Fauzia, Fajriana Shafira Nurrusyda
https://doi.org/10.35118/apjmbb.2025.033.1.07

Abstract

The rapid decline in fossil fuel availability has driven a high demand for alternative fuels, including bioethanol. Bioethanol produced from starchy, sugary, or lignocellulosic materials through hydrolysis and fermentation by microorganisms, especially Saccharomyces cerevisiae. During fermentation, the yeast cell exposed to various stress factors that can reduce the ethanol productivity. One of the means to improve yeast cell tolerance against various stress factors is by supplementing fermentation media with metal ions. Metal ions have important role to increase the rate of sugar conversion to ethanol, cell viability and stress tolerance, and also the degree of final ethanol yield. This study aimed to determine the optimum concentrations of metal ions (calcium, magnesium, and zinc) in yeast nitrogen base (YNB) media for achieving the highest ethanol yield using S. cerevisiae Pinnacle S. The optimum condition was determined using response surface method – central composite design (RSM-CCD) approach. The results of this study indicate that the optimum concentrations of calcium, magnesium, and zinc ions for bioethanol production in YNB media are 26.36 mg/L, 31.82 mg/L, and 68.64 mg/L, respectively. Under these conditions, the maximum ethanol yield achieved was 0.197 g/g, representing a 4.8% increase compared to the central point (0.188 g/g), which was considered the baseline result.

Keywords:

bioethanol, fermentation, metal ions, Saccharomyces cerevisiae