Ethanol Production from Molasses Using an Indigenous Strain of Thermotolerant Kluyveromyces marxianus Under Controlled Conditions

Abstract

Ethanol produced by a fermenting renewable crop such as sugarcane molasses is a very cheap source of alternative fuel. All the developed and some developing countries have taken up bioethanol as an alternative energy source. This situation arises because of the depletion of the fossil fuel reserves, rising costs, and environmental impacts. This study shows that a newly indigenous strain isolated as a mutant strain of thermotolerant Kluyveromyces marxianus M15 produced a maximum production of ethanol in 48 h. The kinetic parameters have been studied for cell growth, substrate consumption, and ethanol production for wild and mutant strains of K. marxianus M15. It has been observed that the wild strain was growing up to 55°C, while the mutant strain was growing up to 65°C. In this study, the mutant strain M15 was proved to be stronger than its parental culture due to its microbial activity. K. marxianus were grown in a 23-l fermentor (working volume 15 l) on different substrates, including glucose, sucrose, and molasses at concentrations of 10, 12, 15, and 17%. Total sugars were tested for their ability. M15 produced maximum ethanol of 72.5–75.2 g l⁻¹ with concentration of 15%, and β-fructofuranosidase (F-Fase) at 72 and 48 h, respectively.