EXTRATO DE LÚPULO NO CONTROLE BACTERIANO EM USINAS DE ETANOL

Abstract

The ethanol production in Brazil is made by fermentation, and competition between the microorganisms of process (yeasts) and the alcoholic fermentation contaminants (bacteria) that use the substrate (sucrose) for its metabolism can occur. Bacteria produce undesirable substances, such as organic acids, the main one being lactic acid, which is the most important group in the fermentation process, by diverting the transformation of ethanol into other undesirable substances. Due to the damage caused by the bacteria in the fermentation process, the use of antibiotics or antimicrobials is necessary to their control. Antibiotics, most commonly used, cause microbial resistance and leave residues in the yeast after drying, which is used as feedstock in the preparation of animal feed or food ingredient for humans. To meet the numerous market requirements, in some countries it is not acceptable to use yeasts for animal feed or even human food that present antibiotic residues, the sugar and alcohol plants started eliminating the use of conventional antibiotics in their fermentation process. Therefore, the use of natural antimicrobials that do not cause bacterial resistance and leave no residues is becoming more frequent. This work aimed to verify the antimicrobial efficiency derived from hops in different dosages in bacterial populations control during the fermentation process of industrial ethanol production. It was concluded that the antimicrobial based on hops (LactoStab) has efficiency in reducing bacteria in several dosages, however due to the high added value of hops the 20 ppm dosage is satisfactory as a result of the bacterial population reduction.

Keywords: Yeasts; Bacteria; Hops Extract; Contaminants.