Ethanol is an important bioproducts used in the field of clean energy. It is produced through the fermentation of sugars by various microorganisms.
Yeast and bacteria are found in terrestrial and aquatic environments and can be isolated from natural substances such as soil, fruits, and vegetables. Yeasts, particularly Saccharomyces cerevisiae, are the primary organisms used in ethanol production due to their efficiency and adaptability. Bacteria such as Bacillus subtilis also play an important role in this process, offering an alternative or supplementary method of fermentation. The choice of microorganism depends on some factors like substrate availability, desired ethanol yield, and process conditions.
This study aims to isolate and identify several yeasts and bacterial isolates, evaluate the production ethanol, molecularly characterize the producing isolates, and to improve some isolates to produce more Ethanol. Fifty different isolates were collected from contaminated fruit and vegetables. Three isolates were identified as S. cerevisiae by PCR specific DNA primers, while 47 isolates were bacterial isolates. All the yeast and bacterial isolates were screened for bioethanol productivity. The bacterial isolate LS-6 showed the highest bioethanol productivity (50%), which was identified by 16S rRNA gene sequencing as B. subtilis. Yeast isolate (CJ-12) and bacterial isolate (LS-6) were subjected to UV- mutagenesis to improve the bioethanol productivity, all obtained mutants from the two yeast and bacteria isolates showed higher productivity compared to the wild-type.