Potentiality of Saccharomyces boulardii in fermentation of bio-ethanol derived from fruit wastes

An astronomical increase in vehicular usage has led to the depletion of existing fossil fuels and forced researchers to find alternative sources of fuels. Extensive studies are utilizing Saccharomyces cerevisiae for bioethanol production. Therefore, in the present study, the potential application of Saccharomyces boulardii derived bioethanol from fruit wastes was explored. The orange, sweet lime, and banana peels were subjected to various pre-treatment procedures and used as substrates for yeast mediated fermentation. The cellulosic de-linearization of fruit peels induced by alkaline and steam pre-treatments was analysed using Fourier Transform Infrared Spectroscopic analysis. The chemical nature of fruit waste-derived bioethanol was compared with commercial ethanol using gas chromatographic analysis. Bioethanol used in ratios 0%, 4%, 8%, 12% by volume as part of fuel blends were subjected to performance testing. This testing process was carried out on a single-cylinder, four-stroke spark-ignition engine and the effect of bioethanol content (by volume) on the operational parameters like total fuel consumption, brake specific fuel consumption, brake thermal efficiency, volumetric efficiency, and equivalence ratios were assessed. FTIR spectra showed significant changes in the chemical structure of fruit peels due to pretreatments. The bioethanol yields increased up to 24 h of fermentation after which there was a steady decline. These results were confirmed by an increase in pH of the biomass after 24 h up to 72 h. Enzymatic hydrolysis of fruit peels resulted in higher bioethanol yield as compared to acid treatment. The fruit derived bioethanol showed ideal physicochemical characteristics for use as automobile fuel. The same showed decent performance when tested on a four-stroke, spark ignition engine.