Isolation, Characterisation and Identification of Probiotics Lactobacillus Species in Pekasam (Fermented Fish)

The genus Lactobacillus in fermented foods is commonly associated with probiotic properties. Probiotics are living microorganisms in foods and supplements that provide benefits to improve the balance of intestinal microbiota. The purpose of this study was to isolate, characterise, and identify Lacto...

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Main Author: Nur Liyana Binti Kamal
Format: Thesis
Language:English
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Summary:The genus Lactobacillus in fermented foods is commonly associated with probiotic properties. Probiotics are living microorganisms in foods and supplements that provide benefits to improve the balance of intestinal microbiota. The purpose of this study was to isolate, characterise, and identify Lactobacillus from traditional fermented fish or pekasam. A total of 117 isolates were isolated from four samples by using MRS agar. At the beginning of the study, alla bacterial isolates were tested for Gram staining and catalase test. Of these, only 21 bacterial isolates are identified as Gram-positive, rod-shaped and catalase-negative. Then,21 bacterial isolates were tested with a test of tolerance to acid at pH 4, pH 3 and pH 2 as well as a test tolerance of bile of cattle at three different percentages of bile salts at 0.3%, 0.5% and 1.0% In these tests, only 9 isolates can survive in acidic and bile environment. Next, these 9 isolates were tested antimicrobial activity against six bacterial foodborne pathogens of Salmonella typhimurium, Bacillus cereus, Bacillus subtilis, Escherichia coli, Staphylococcus aureus and Astaphylococcus epidermidis.In this test, only 6 out 9 strains of bacteria have good inhibition against the tested pathogenic bacteria. Hydrophobicity tests were done to identify the extent of the 6 strains of these bacteria can live well under anaerobic conditions.The test results have shown that only one isolate showed the hydrophobicity exceeds 50%. The isolate was identified using API 50 CHL as Lactobacillus plantarum. The results of this study confirm that pekasam, the traditional fermented foods contain probiotics Lactobacillus which have a potential to be used as starter cultures in food products. However, molecular studies of these isolates should be done in detail to see which genes act as probiotic properties in the human gut as well as on safety in food products.