STUDY OF A RICINUS COMMUNIS L. (CASTOR OIL) DERIVATIVE AS A BIOCIDAL AGENT AND VISCOSITY REDUCER ON LEUCONOSTOC MESENTEROIDES IN THE SUGAR AND ALCOHOL INDUSTRIES

ABSTRACT Castor-oil, extracted from seeds of Ricinus communis L., is normally used in natura or in its modified form in the medical, pharmaceutical and industrial areas. One of its chemical derivates – Poliquilgerm® – has shown antifungal properties on Candida albicans, and bacteriostatic/bactericide effects on Escherichia coli reaching 99.9%. Considering these features, in the present study Poliquilgerm® was applied in cultures of Leuconostoc mesenteroides, a frequent contaminant bacterium of musts in the sugar and alcohol industries. This bacterium, when a contaminant of must, produces lactic acid as well as dextran, a polymer of glucose which may increase the viscosity of fluids in the operation. The present study evaluated the effect of different concentrations of Poliquilgerm® on viscosity produced by L. mesenteroides cultures under different conditions of various culture media, pH and temperature. A 20.56% decrease in viscosity was verified when 1.0% of the product was used, and bacterium growth inhibition after 20 hours in media with 1.0 and 0.2% of Poliquilgerm®. L. mesenteroides showed a higher growth rate in pH 6.0, at both 28 and 33º C, evidenced by greater biomass production. Also, in the culture media at this pH a greater decrease in viscosity percentages was verified at both concentrations used. The media with these same concentrations reached up to 100% decrease of UFC/mL after 24 hours in the presence of the product, observed by biomass quantification and confirmed by the Pour Plate technique.