Isolation and identification of lactic acid bacteria with antimicrobial properties from fermented food products
Lactic acid bacteria (LAB) are "Generally Recognized as Safe" (GRAS) microorganisms that play an important role in the fermentation of animal and vegetable substrates. They may produce antimicrobial peptides that have high and promising potential to inhibit the growth of spoilage pathogeni...
שמור ב:
| Main Authors: | , |
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| פורמט: | Proceedings Paper |
| שפה: | English |
| יצא לאור: |
Malaysian Society for Microbiology
2021
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| נושאים: | |
| גישה מקוונת: | http://agris.upm.edu.my:8080/dspace/handle/0/19649 |
| תגים: |
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| סיכום: | Lactic acid bacteria (LAB) are "Generally Recognized as Safe" (GRAS) microorganisms that play an important role in the fermentation of animal and vegetable substrates. They may produce antimicrobial peptides that have high and promising potential to inhibit the growth of spoilage pathogenic bacteria. The objectives of this study were to isolate and identify LAB from Yakult, Vitagen, yoghurt, tempeh and chili paste and determine the antimicrobial properties of the LAB. De Man, Rogosa and Sharpe (MRS) agar was used for its isolation. The isolated bacteria were picked and cultured to obtain pure colonies. The colonies were identified using Gram stain, spore stain, catalase, oxidase and triple sugar iron tests. All the bacteria isolated were Gram positive, catalase and oxidase negative. Nineteen isolates showed the same results for triple sugar iron test. The isolates were then tested using antimicrobial assays namely well diffusion, minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC). From the 23 isolates, 6 isolates displayed antibacterial activity against Staphylococcus aureus, Escherichia coli, Bacillus cereus and Pseudomonas sp. The lowest MIC obtained was 8.2 log CFU mr. Inhibitions obtained in all six isolates were bacteriostatic. These six isolates were assayed for antibacterial compounds synthesized against test microorganisms by extracting the peptides from the supernatant and then checked with reverse-phase high-performance liquid chromatography (RP-HPLC). Peaks obtained showed that there were peptides present in the cell-free supernatant. Rep-PCR divided the isolates with antimicrobial properties into 2 groups and 16S rRNA gene sequencing identified them as Staphylococcus warneri and Lactobacillus paracasei. |
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