Isolation and characterization of lactic acid bacteria and yeasts from the Brazilian grape sourdough

Sourdough is a mixture of flour and water fermented by lactic acid bacteria and yeast, with a large use in bakery products. This study was developed with Brazilian grape (Niagara rosada) sourdough obtained from spontaneous fermentation. The aim of this work was to characterize genotypic and phenotypically lactic acid bacteria and yeasts isolated from sourdough. The phenotypic identification for bacteria and yeasts was performed by using the kit API50CHL and 20CAUX and the genotypic characterization was performed by sequencing method. A total of four isolated strains were analyzed in this study. Two of these strains were phenotypically and genotypic identified as Lactobacillus paracasei and one as Saccharomyces cerevisiae. Another sample phenotypically identified as Candida pelliculosa did not show the same identity by sequencing. It shows the need to use phenotypic and genotypic characterization associated for the correct microorganism identification.

酸面团（Sourdough）是由面粉与水经乳酸菌和酵母发酵制成的混合物，在烘焙食品中应用广泛。本研究以经自然发酵得到的巴西葡萄（Niagara rosada）酸面团为材料开展。本研究旨在对从酸面团中分离得到的乳酸菌与酵母进行基因型与表型鉴定分析。细菌与酵母的表型鉴定采用API50CHL与20CAUX试剂盒完成，基因型表征则通过测序法实现。本研究共分析了4株分离菌株。其中2株菌株经表型与基因型鉴定为副干酪乳杆菌（Lactobacillus paracasei），另有1株鉴定为酿酒酵母（Saccharomyces cerevisiae）。另有1株经表型鉴定为薄膜假丝酵母（Candida pelliculosa）的菌株，经测序验证并未得到一致的鉴定结果。该结果表明，为实现微生物的准确鉴定，需将表型表征与基因型鉴定结合使用。