Title

Screening of lactic acid bacteria isolated from traditional fermented products: Potential probiotic bacteria with antimicrobial and cytotoxic activities

Date of Publication

2015

Document Type

Master's Thesis

Degree Name

Master of Science in Biology

Subject Categories

Biology

College

College of Science

Department/Unit

Biology

Thesis Adviser

Esperanza C. Cabrera

Defense Panel Chair

Delia C. Ontengco

Defense Panel Member

Chona Camille E. Vince Cruz
Patricio Elvin L. Cantiller

Abstract/Summary

Thirty (30) isolates of lactic acid bacteria (LAB) from traditionally-prepared fermented products specifically fermented soy-bean paste, fermented mustard and fermented rice-fish mixture were studied for their in vitro antimicrobial and cytotoxic activies. Seventeen (17) isolates were identified as Lactobacillus plantarum, while 13 isolates were identified as Enterococcus spp using 16s rDNA sequences. Disc diffusion method was used to determine the antibacterial activity of LAB against Staphylococcus aureus (ATCC 25923) and Escherichia coli (ATCC 25922), while the modified agar overlay method was used to determine the antifungal activity of LAB isolates on the yeast Candida albicans, and the dermatophytes Microsporum gypseum, Trichophyton rubrum and Epidermophyton floccosum. The filter-sterilized LAB supernatants were evaluated for their cytotoxicity to mammalian colon cancer cell lines (HT-29 and HCT116) and normal human dermal fibrolasts (HDFn) using resazurin assay (PrestoBlueTM) . Colchicine was the positive control. No antimicrobial activity was observed against the bacterial test organisms and the yeast Candida albicans. On the other hand, all of the tested LAB strains were fungicidal for all the test dermatophytes. Cytotoxicity index profiles of the supernatants of the 15 randomly picked LABs and negative control (brain heart infussion broth) suggest nontoxicity to the cells when compared to colchicine, whereas all LAB supernatants were found to be cytotoxic to HT- 29 and HCT116 colon cancer cell lines. Results provide strong support for the role of the lactic acid bacteria studied in antimicrobial treatment and anticancer therapy.

Abstract Format

html

Language

English

Format

Electronic

Accession Number

CDTG006531

Shelf Location

Archives, The Learning Commons, 12F Henry Sy Sr. Hall

Physical Description

1 computer optical disc ; 4 3/4 in.

Keywords

Lactic acid bacteria; Anti-infective agents; Probiotics

This document is currently not available here.

Share

COinS