Production of ethanol by Saccharomyces cerevisiae from byproduct of sugar industry in a batch fermentation system

Subject Areas : environmental management

Farshid Ghorbani ¹ (Faculty of Natural Resources and Marine Sciences, Tarbiat Modares University)
Habibollah Younesi ² (Faculty of Natural Resources and Marine Sciences, Tarbiat Modares University)
Abbas Esmaeili Sari ³ (Faculty of Natural Resources and Marine Sciences, Tarbiat Modares University)
Seyed Mahmoud Ghasempouri ⁴ (Faculty of Natural Resources and Marine Sciences, Tarbiat Modares University)
Malihe Amini ⁵ (Faculty of Natural Resources and Marine Sciences, Tarbiat Modares University)
Ali Daneshi ⁶ (Faculty of Natural Resources and Marine Sciences, Tarbiat Modares University)

Received: 2007-12-01 Accepted : 2008-03-03 Published : 2009-12-22

Keywords: Saccharomyces cerevisiae, Ethanol, cane molasses, batch fermentation, cane Industry,

Abstract :

A great amount of agricultural wastes are produced in Iran, which can be converted into suitable sources of ethanol production. Molasses is one of the cheapest and most frequent carbon sources which are available for ethanol production. This application, besides preventing molasses from entering the environment, produces a clean fuel which is compatible with nature. The main goal of this study was to produce ethanol as a clean and environment-friendly fuel. To this end, the biosynthesis of ethanol was conducted by Saccharomyces cerevisiae PTCC5010, using cane molasses as substrate through batch fermentation processes. Experiments were carried out at the ambient temperature (25o C) and pH 4.5. Batch ethanol production was carried out with 10, 20, 30, 40, and 50 gl-1 of cane molasses. The total sugar consumption, maximum ethanol production, and productivity at 50 gl-1 of molasses were 93.27%, 9.3 g ethanol/l molasses,and 0.24 g ethanol/g total sugar,respectively. However, the maximum cell dry weight and biomass yield were 5.15 g CDW/l and 0.18 g CDW/g total sugar, respectively. The results showed that the applied substrate could indeed support the production of a sustainable biofuel. These alternatives exhibited comparable biological activity in comparison with the fuels obtained using more costly biomasses. . Also, ethanol can be substituted with fossil fuels because of the low pollution produced as a result of its combustion