The Control of Lactobacillus sp. by Extracellular Compound Produced by Pseudomonas aeruginosa in the Fermentation Process of Fuel Ethanol Industry in Brazil

Abstract

This work evaluated the effect of secondary bacterial metabolites produced by Pseudomonas sp LV strain in control of Lactobacillus sp. population in the microcosm of the vat during ethanol fermentation. The fraction F4 produced by Pseudomonas aeruginosa was extracted with dichloromethane and fractionating by vacuum liquid chromatography ob-tained in a methanol phase. The evaluation of antibiotic activity of F4 fraction mixed or not with sulphuric acid and Kamoram ® . The antibiotic activity of F4 fraction was determined as well as the fermentation efficiency. Also was de-termined yeast cell viability, budding formation, the viability of budding cells, and number of populations of Sac-charomyces cerevisiae and Lactobacillus sp. The results showed that the F4 fraction had high selective antibiotic ac-tivity against Lactobacillus sp. but not for S. cerevisae, and no inhibitory effect was observed in the fermentation proc-ess by yeast. Also F4 fraction decreased flocculation and foam formation. The F4 has an antibiotic activity against Lac-tobacillus sp. and should be used as an alternative to control bacteria contamination and foam and flocculation forma-tion in the fuel ethanol fermentation process. The F4 fraction could reduce the use of antibiotics in the control of Lac-tobacillus sp. population during the fuel ethanol production.