Characterization of ethanol producing yeasts isolated from Garcinia indica and Syzygium cumini

Biofuels are commonly recognized as the prospective rivals fighting against our age-old reliance on fossil fuels. Rising demand for fuel economy, environmental sustainability and availability of energy has drawn global attention to liquid biofuels. In India, sugarcane molasses is the main resource for bioethanol development and raw material supply inconsistency holds the major responsibility for sluggish response to blending targets. As the biofuel mass production is under developmental stage, the need for alternative ways to produce the sustainable energy is encouraged all across the globe. Therefore, the main objective of this study is to report the bioethanol producing ability of the yeasts isolated from natural sources. This study was conducted to characterize the three isolates obtained each from Garcinia indica (kokum) and Syzygium cumini (jamun) extracts. The isolated yeasts (here referred to as K1, K2 and K3 from kokum; J1, J2 and J3 from jamun) were subjected to various assays to determine their qualities for industrial applications. The microscopic, morphological and biochemical characteristics of all the strains were studied. All the yeast strains were found tolerant against pH range from 3 to 10 and were able to grow at temperatures like 25ºC and 37ºC suggesting them as being mesophilic. All the strains could also utilize the provided eight carbon sources (sugars) after a varied interval of incubation. The most favored sources of carbon were fructose and dextrose. Among kokum-isolated yeasts, K2 yielded the highest alcohol yield (51.34 mg / ml) while J3 produced maximum alcohol (54.20 mg / ml) among the jamun strains.