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Journal of Biological Sciences

Year: 2018 | Volume: 18 | Issue: 6 | Page No.: 260-269
DOI: 10.3923/jbs.2018.260.269
Isolation and Molecular Identification of Food Grade Lactic Acid Bacteria and Their Antifungal Activity
Soher El-Sayed Aly, Nivien Abdelrahman Abo-Sereih , Rasha Gomma Salim and Amal Shawky Hathout

Abstract: Background and Objective: The presence of pathogenic fungi in grains has been a global concern due to their economic effects. Recently, biological control methods have become an important strategy to control pathogenic fungi. Therefore, the aim of this study was to isolate and identify food grade lactic acid bacteria and screen their antifungal activity against pathogenic fungi isolated from peanuts. Materials and Methods: Lactic acid bacteria were isolated from dairy products. The lactic acid bacterial cell-free supernatants and bacteriocins were studied for the antifungal activity against fungal species isolated from peanut samples. The two lactic acid bacteria isolates and their bacteriocins that showed antifungal activity were identified using morphological, biochemical and molecular techniques. Results: A total of 20 lactic acid bacteria were isolated from traditional dairy products. Meanwhile, a total of 90 fungal isolates were isolated from peanut samples. Aspergillus (55%) was the dominant genus including five species namely, A. parasiticus, A. flavus, A. ochraceus, A. terreus and A. niger. Fusarium, Penicillium and Trichoderma genera were also isolated but in a lower frequency. Both lactic acid bacterial cell-free supernatants and their bacteriocins showed antifungal activity against fungal species isolated from peanut samples and were thus identified using the molecular 16S rDNA gene sequencing. Lactic acid bacteria isolates 11 and 12 showed 99% homology with Enterococcus faecalis and Enterococcus faecium, respectively. Their sequences were deposited in the GenBank databases under accession number MF000305.1 and MF000307.1. Conclusion: This study revealed the probability of using these Enterococcus isolates in food preservation. The partial or total sequencing of the 16S ribosomal DNA (rRNA) gene showed a fast technique for bacterial classification.

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How to cite this article
Soher El-Sayed Aly, Nivien Abdelrahman Abo-Sereih, Rasha Gomma Salim and Amal Shawky Hathout, 2018. Isolation and Molecular Identification of Food Grade Lactic Acid Bacteria and Their Antifungal Activity. Journal of Biological Sciences, 18: 260-269.

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