Characterization of yeast strains from handia a traditional fermented beverage and the possibility of their application in winery

Abstract

The thesis describes work that can be divided into four chapters. The first part describes newlinethe work with isolation and identification of microorganisms from Handia. A variety of yeast strains and bacteria were isolated from Handia samples collected from different localities of tribal villages, in West Bengal. All the microorganisms present in Handia have been successfully identified to species level. A total of 12 yeast strains belonging to four genera were detected newlinefrom the samples of Handia. These were designated as Saccharomyces cerevisiae KpY, S.cerevisiae 18VSL, S. cerevisiae H15, S. cerevisiae H17, Hanseniaspora guilliermondii G1, H. guilliermondii G4, Issatchenkia orientalis H21L, Candida glabrata H3, C. glabrata H8, C. glabrata H11, C. glabrata H12 and C. tropicalis 18VLL. I followed a number molecular techniques involving 26S rRNA gene sequence analysis, 5.8S ITS fingerprinting and RAPDPCR using M13 primers. The bacterial species identified from Handia by 16S rRNA gene sequence analysis were Brevibacillus agri BA, Leuconostoc sp. B16 and Kocuria sp. B4. This is the first report to explore the microbial composition of Handia. newlineThe second part is aimed at the physiological and biochemical characterization of these newlinemicroorganisms. The parameters (pH, temperature) that influence microbial growth have been studied. In addition sugar tolerance, ethanol tolerance; flocculation ability, hydrogen sulfide production and ability to grow at various concentrations of glucose and fructose have been evaluated. newlineThe third focuses on assessing the potential of the microorganisms to ferment grape newlinejuice. The kinetics of growth during fermentation in grape juice at 180C has been studied. Further, pH and titratable acidity before and after fermentation in grape juice have been evaluated in order understand their efficiency to ferment grape juice. Finally some of the important components (ethanol, propanol, methanol, butanol, acetaldehyde) produced in wine have been analyzed.