Paper Title
Use of Wild Yeasts including a Rhodotorula Spp. on Bioethanol Production

Abstract - Brazilian industrial processes of alcoholic fermentation are distinguished from other fermentations by using a large volume of yeast cells and continuous back-slopping cycles during all the sugarcane harvest. A major barrier to be over comed in the fermentation process is the competition between microorganisms, where the selected yeasts have the challenge of competing with the entire microuniverse coming from the field, from which, in most cases, other microorganisms work against the industrial process and as the rate of resource inflow increases, fermenting microorganisms progressively outnumber respirators. This is because higher resource influx rates lead to increased competition, essentially because population density increases and fermenters achieve better performance than respirators. Based on these metabolic interpretations, this work aimed to evaluate the efficiency of 5 wild type yeasts in the alcoholic fermentation of sugar cane juice on a laboratory scale, comparing the efficiencies presented by these isolated microorganisms with the fermentation efficiencies using yeast mix with a non-fermenting wild yeast,Rhodotorula spp., thus promoting cooperation and competition in the fermentation process. Fermentation efficiency results were expressed in terms of the amount of bioethanol determined by gas chromatography; cell viability of yeasts, assessed by cell counting in a Neubauer chamber; and sugar consumption assessed by measurement with DNS reagent in spectrophotometer. It was concluded that the tested yeast mix containing a Rhodotorula spp. promoted fermentative efficiency gain in bioethanol production compared to fermentation in the presence of isolated samples. Keywords- Alcoholic Fermentation; Bioethanol; Yeasts Mix; Wild Yeasts.