Screening and characterisation of lactic acid bacteria isolates as potential probiotic from different stages of soybean tempe processing / Balqis Pisol

Nowadays, health consciousnesses among the consumers are increasing. The market of healthy food like ready fermented food is in demand especially ready fermented food with probiotic as they commonly contain lactic acid bacteria (LAB). However, the information of LAB presence during the processing stages of fermented food is still scarce. Therefore, isolation of LAB from tempe was carried out at different stages of tempe processing to examine the occurrence of LAB and to identify the isolates with the most promising potential as probiotic. Isolation was done using conventional plating method while morphological, physiological and chemical characteristics with the use of API 20 Strep, API 50 CHL kit and 16S rRNA gene sequences were employed to identify the LAB isolates. Acid (pH 1.5, 2.0. 4.0, 6.5 and unmodified broth) and bile (0.3%) tolerance along with antimicrobial activity tests were conducted to screen for probiotic characteristics. A total of 14 LAB isolates were obtained from all stages. Identification of all LAB isolates using API kits revealed isolates A, B, C, D, E, F and I as Enterococcus faecium, isolates G, H, M and N as Leuconostoc mesenteroides and isolate J as Lactobacillus plantarum. Isolate K and L however were unable to be identified. Molecular identification using 16S rRNA had revealed that isolate G (Leuconostoc mesenteroides) and J (Lactobacillus plantarum) were re-identified as Leuconostoc lactis and Leuconostoc spp. respectively. Whereas, two previously unidentified isolates were identified as Alicyclobacillus spp.