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124237

Antibacterial Bioactivity of Some Lactic Acid Bacteria Isolated from Various Egyptian Products

Article

Last updated: 22 Jan 2023

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Abstract

The current research aimed to isolate and screening of antibacterial bioactive lactic acid bacteria (LAB) from different foods such as raw milk, dairy products and fermented meat and evaluate their potential for production of antibacterial substances, namely bacteriocins. Ten samples were collected from different market foods, examined and used for LAB isolation on MRS medium. A total of 71 bacterial isolates were selected based on some variation properties, such as color, shape, size and oxygen requirements. These isolates were confirmed as lactic acid bacteria based on their microscopic observation and chemical properties, i.e. catalase negative and acid producing from glucose fermentation. All selected isolates were grown on MRS medium at 37ºC for 48 h, and compared to identified LAB strains, i.e. Lactococcus lactis, Streptococcus thermophilus, Befidobacterium sp, Lactobacillus casi, Lb rhamnosus, Lb. acidophilus, Lb. helveticus and Lb. plantarum. Isolates and strains were surveyed for bacteriocin production as inhibitory activity test. Partial purification of bacteriocin was carried out by salt precipitation method; this method was done by ammonium sulphate 40-60% saturation and centrifuged at 9500 rpm for 20 minutes at 4ºC. Some of microbial indicator strains found to test by inhibitory biological activity substance (partial purification of bacteriocin) produced by lactic acid cultures. Indicator strains such as staphylococcus aureus, Listeria monocytogenes and others were grown by nutrient agar at 37º C for 24h. An inhibitory activity test was executed by paper diffusion method. The inhibition effect was examined by form clear inhibition zone around indicator strains. Twenty-eight isolates and the 8 LAB strains showed bioactivities against the tested pathogens. Gram positive indicator bacteria were found to be the most sensitive to inhibitory substances produced by LAB culture as compared to gram negative indicator strains. Staphylococcus aureus was exhibited the highest sensitivity to it. The highest bacteriocins activities were produced by strain Lactobacillus rhamnosus while R5 and S6 from LAB isolates. They were shown broad spectrum against gram positive and gram-negative pathogenic bacteria. Diameters of inhibition zone refer to degree of sensitive between indicator strains and bacteriocin activity

DOI

10.21608/ajs.2020.38231.1236

Keywords

lactic acid bacteria, MRS medium, Antibacterial agent, bacteriocin, Paper diffusion method

Authors

First Name

Amir

Last Name

Kamel

MiddleName

-

Affiliation

Department of Radiation Microbiology, National Center of Research and Radiation Technology, Egyptian Atomic Energy Authority, Cairo, Egypt.

Email

amirkamel2005@yahoo.com

City

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Orcid

0000-0003-0142-7789

First Name

Azhar

Last Name

El-Sayed

MiddleName

-

Affiliation

Department of Agricultural Microbiology, Faculty of Agriculture, Ain Shams University, Cairo, Egypt.

Email

azhar_elsayed@yahoo.com

City

-

Orcid

-

First Name

Bothaina

Last Name

Youssef

MiddleName

-

Affiliation

Department of Radiation Microbiology, National Center of Research and Radiation Technology, Egyptian Atomic Energy Authority, Cairo, Egypt.

Email

bothainaeba@gmail.com

City

-

Orcid

-

First Name

Shaimaa

Last Name

Amin

MiddleName

-

Affiliation

Department of Agricultural Microbiology, Faculty of Agriculture, Ain Shams University, Cairo, Egypt.

Email

dshimaaamin@gmail.com

City

-

Orcid

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Volume

28

Article Issue

4

Related Issue

23211

Issue Date

2020-12-01

Receive Date

2020-08-10

Publish Date

2020-12-01

Page Start

1,117

Page End

1,130

Print ISSN

1110-2675

Online ISSN

2636-3585

Link

https://ajs.journals.ekb.eg/article_124237.html

Detail API

https://ajs.journals.ekb.eg/service?article_code=124237

Order

128

Type

Review Article

Type Code

669

Publication Type

Journal

Publication Title

Arab Universities Journal of Agricultural Sciences

Publication Link

https://ajs.journals.ekb.eg/

MainTitle

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Details

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Article

Created At

22 Jan 2023