Antagonism research between lactic acid bacteria, yeasts and acetic acid bacteria isolates obtained from spontaneous cocoa beans fermentation

• Grant number: 18/06627-9
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: June 01, 2018
• End date: November 30, 2018
• Field of knowledge: Biological Sciences - Microbiology
• Principal Investigator: Elaine Cristina Pereira de Martinis
• Grantee: Maria da Graça Landim Bravo
• Host Institution: Faculdade de Ciências Farmacêuticas de Ribeirão Preto (FCFRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil

Abstract

The spontaneous fermentation of cocoa beans process is a relatively synchronized microbial succession which depends on metabolites and exchange of carbon sources among microorganisms. Lactic acid bacteria (LAB) are dominant during fermentative process and, consequently, during the succession. Our literature review indicated LAB are not desirable in the process and the presence of lactic acid, a non-volatile metabolite may even enhance the bitterness of final product, linked to low acceptation of final product. Our objective for this project is to evaluate the antagonism exerted by LAB on yeast and acetic acid bacteria (AAB) populations. Antagonism assays will be carried out between yeasts vs. LAB and LAB vs. AAB to analyze if there is any AAB able to survive in the presence of antagonistic metabolites of LAB. In this way, we intend to advance the research that is under way in our laboratory to obtain a starter culture to increase the quality and yield of fermented.