Fermentation of sugar cane juice (Sacharum officinarum) cultivar RB 7515 by wild yeasts resistant to UVC

Abstract

Commercial alcoholic fermentations coexist with microbial contamination come together withsugar cane or industrial water. The contaminants are bacteria or wild yeast that also results reduction in yield. The contaminants control use acid treatment and antibiotics. Disinfection by ultraviolet radiation is efficient in transparent liquid and has as advantage leaving noresidues. Reports on the UV effect over microorganisms in turbid and colored liquids are scarce. The research evaluated the use of commercial UVC lamp in continuous reactor for reducing microbial load and its effect on the fermentation of sugarcane cultivar RB 7515. The sugar cane juice and tap water used in dilution were both exposed to doses of 0, 500, 1000, 2000 and 4000 Joules/ljuice. The counts were made in specific culture media. The dose 500 Joules/liter was enough to eliminate the coliforms, but survived yeast and bacteria without difference to the others dose. The treated sugar cane juice was diluted to 12 Brix and fermented by the surviving wild yeasts untilBrix stabilization. The alcoholic graduation was 5° GL for all the treatment. It was proved the ability of wild yeasts resistant to UVC even with long fermentation times.