Issues in Biological Sciences and Pharmaceutical Research
Vol.2(9),pp. 106-114,October 2014
Article ID/14/BSPR/056/09 pages
Author(s) agree that this article remain permanently open access under the terms of the Creative Commons Attribution License 4.0 International License.
Original Research Article
Anti-pseudomonas activity of organic acids produced by lactic acid bacteria
Beatrice Folawe Okorhi
School of Environmental Sciences, Federal University of Petroleum Resources Effurun Delta State Nigeria.
Author E.mail: damisabeatrice(at)yahoo.ca
Fifteen Lactic acid bacterial (LAB) strains were isolated from milk and milk products. They were identified as Lactobacillus plantarum(3)Lactobacillus fermentum (2), Lactococcus lactis subspecie cremoris(3) Lactobacillus acidophilus (3), Lactobacillus brevis (3) and Streptococcus thermophillus (1). The entire LAB isolated inhibited all the Pseudomonas species with the exception of Lactococcus lactis subspecies cremoris that did not inhibit Pseudomonas putida, Pseudomonas aeroginosa III and Pseudomonas flourescens. Lactobacillus plantarum produces the highest quantity of lactic acid at 72 hours of incubation (2.89g/l) while Lactobacillus fermentum followed closely (1.11g/l). Inhibitory activity of organic acid such as Lactic, glacial acetic and citric acid was tested against indicator microorganisms. Lactic acid had the highest inhibitory activity against Pseudomonas aeroginosa I and Pseudomonas flourescens with 28mm zones of inhibition each, followed closely by Acetic acid having 20mm zone of inhibition against Pseudomonas aeroginosa III. Citric acid had the lowest zone of inhibition (12mm) against Pseudomonas putida I and Pseudomonas putida II. Results of the high performance liquid chromatography (HPLC) used to quantify organic acid revealed that, Lactobacillus plantarum produced the highest yield of Lactic acid (280.16 mg/ml) closely followed by Lactobacillus fermentum (215.9 mg/ml). Whereas the lowest yield (48.253mg/ml) was produced by Lactococcus lactis subsp cremoris with the retention time of 3.231. Thus, the present study showed that the antimicrobials produced by LAB have the potential to inhibit pathogenic and food-spoilage microorganisms, especially Pseudomonas species used in this work.
Key words: Lactic acid bacteria, pseudomonas species, organic acid, high performance liquid chromatography, man ragosa sharpe, analytical profile index.