O uso de extrato de orégano (Origanum vulgare ) no controle de bactérias da fermentação etanólica a partir de cana-de-açúcar

Abstract

The fermentation process is an important stage in the production of ethanol, however throughout production it can occur contaminations that directly influence the quality and quantity of ethanol produced. The main group of contaminating bacteria in the production of ethanol in fermentation are Lactobacillus, which can compromise the efficiency of the process, making it necessary to use antibiotics. In view of this scenario, the present study aimed to evaluate the use of oregano extract (EO) as a natural antibacterial to control these microorganisms. The oregano extract was produced in the laboratory under sterile conditions 24 hours before use. It was applied in four concentrations, 400, 600, 800 and 1000 ppm. Based on these concentrations, the effect of the extract on contaminating bacteria and yeasts was evaluated, based on the number of initial cells and after the inoculation of the extract, comparing it with the commercial antibiotic used in sugar and alcohol plants. To carry out the study, fermentation took place in six hours. The results revealed that after fermentation the oregano extract showed a control effect on the contaminating bacteria. At the highest concentration tested (1000 ppm), EO reduced approximately 73% of the initial microbial load. In this way the results demonstrated that the oregano extract proved to be promising for the control of contaminating bacteria in the ethanolic fermentation process, as well as not compromising the development of fermentative yeasts.