Screening for antagonistic activity of lactic acid bacteria isolated from the nectar of melliferous plants against Lactobaccilus plantarum and selected food borne pathogens.

Date

4-2013

Degree

Bachelor of Science in Biology

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Jamora, Renard M.

Committee Member

Cruz, Wilma T.

Abstract

Seventeen putative lactic acid bacteria were isolated from the nectar of four melliferous plants namely, Actinophleus macarthurii, Cocos nucifera, Helianthus anuus, and Moringa oleifera. All bacterial isolates were found to be catalase negative, Gram positive and non-endospore forming. Fifteen were cocci in shape and the rest were rods. Majority of the isolates were aerotolerant anaerobes and only four were facultative anaerobes. Twelve isolates were observed to be heterofermentative while five were homofermentative. Primary screening for antagonistic activity of the bacterial isolates using the Agar-plug method revealed that three isolates were antagonistic against Enterococcus faecalis, seven against Escherichia coli, and 16 were active against Staphylococcus aureus. None of the isolates exhibited activity against Lactobacillus plantarum. Secondary screening using the Cylinder cup method and two cell-free broth preparations (pH-unneutralized and neutralized) of the antagonistic isolates was done. For the unneutralized broth, results showed that seven isolates were antagonistic against E. coli, 16 against S. aureus and none on E. faecalis. Isolates that exhibited zones of inhibition greater than or equal to 13 mm diameter for S. aureus and 8 mm for E. coli were further screened using pH-neutralized cell-free broth. None of the isolates, however, exhibited activity against the two test organisms.

Language

English

Location

UPLB Main Library Special Collections Section

Call Number

LG 993.5 2013 B4 N53

Document Type

Thesis

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