Isolation and characterization of Lactic Acid Bacteria (Lactobacillus sp) from strawberry (Fragaria vesca)

Abstract

The principle of making yoghurt is fermentation of milk with the addition of lactobacillus (LAB) and Streptococcus bacteria. LAB often found naturally in fruits and vegetables. One of the fruits that is thought to contain lactic acid bacteria is strawberries (Fragaria vesca). Strawberry are thought to be one of the natural media of bacteria including lactic acid, because strawberry contain various chemical compositions that are needed as a substrate for LAB. The purpose of this study is isolate LAB from strawberry and determine the type of LAB produced microscopically. Research methods, the ingredients used are strawberry obtained from community plantations in Aie Angek, Tanah Datar district, with Merck NA media, oxoid MRSa, 0,9% NaCl, crystal violet paint from biological laboratories of Universitas Negeri Padang. Isolation LAB from strawberry done in two ways, the first with plant strawberry tissue directly into the NA medium and the second with fermentation strawberry and then plant the strawberry into the MRSa medium with streak plate methods. The isolates obtained were identified microscopically using a microscope with gram staining method. From the research that has been done, the following result are obtained : (1) Plant strawberry tissue direcly into NA medium and gram staining, there were 2 colonies of gram positive bacteria with bacil cell form. (2). Fermentation strawberry from the results, there were 2 colonies gram positive bacteria with bacil cell form. We can identify this colonies as Lactobacillius bulgaricus.