Author : Nguon Samnang

Summary : A study was conducted to identify the lactic acid bacteria (LAB) present in fermenting bignay and mango wines. Microbial count (total and acid-producing bacteria) of the samples was determined at weekly intervals (0, 7, 14, 21, and 28 days) using the pour plate technique. Results showed that the counts continuously decreased as fermentation progressed. No acid-producing bacteria was found in fermenting bignay wine during the entire 28-day fermentation period. On the other hand , 99 representative colonies of acid-producing bacteria from fermenting mango wine (7, 14, 21, and 28 days) were isolated. After series of isolation and purification, 70 out of 99 isolates were found to be Gram-positive, catalase-negative, non-motile rods. Further test on gas production from glucose was performed and out of 70 isolates, 8 representatives were selected for further phenotypic characterization. Confirmation of their biochemical properties by sugar fermentation pattern analysis was established using the rapid identification kit API 50 CHL. Results indicated that 3 out of 8 isolates were presumptively identified as Lactobacillus pentosus and 5 as Lactobacillus brevis 3. Further confirmatory identification test by 16S rRNA gene sequencing analysis using 27F and 1492R primers revealed that 7 isolates were identified as Lactobacillus brevis, strain KLDS1.0411, partial sequence with homology of 100% similarity and one isolate was 100% identical to the 16S rRNA gene of either Lactobacillus pentosus, stain KLDS1.0411 or Lactobacillus plantarum, stain SC2-6, partial sequences. These results suggest that Lb. brevis and either Lb. pentosus or Lb. plantarum are predominant in the fermentation of mango wine. These results shed some light on the ecology and oenological influence of LAB on the quality of mango wine. Presence of these two strains in fermenting mango wine of the Philippines is reported for the first time. It is hoped that the results of this study can offer useful information for the improvement of mango wine production and other tropical fruit wines.