Bacteriocin Production using Lactic Acid Bacteria Isolated from Ugba (Pentaclethra macrophylla Benth)

Abstract— Lactic acid bacteria (LAB) play vital roles in our everyday life such as in fermentation, preservation and production of wholesome foods. This work is aimed at studying the bacteriocin production of lactic acid bacteria from Ugba (a local condiment) sold in Anambra state. A total of 5 samples of Ugba each were purchased randomly from three locations in Anambra state. Lactic acid bacteria were isolated and characterized using standard microbiological procedures. The isolates were subjected to antimicrobial activities by disc diffusion method while bacteriocin production was achieved by culture on appropriate medium and partially purified by centrifugation method and then characterized. Antimicrobial activities using cell free supernatant and partially purified bacteriocin of the isolates against Escherichia coli, Staph. aureus and Candida albicans found in Ugba were equally assessed. The isolate that gave the highest zone of inhibition was identified by 16s rDNA sequencing and was selected for further assay. Biopreservative study of the choice isolate against Escherichia coli, Staph. aureus and Candida albicans which were extraneously introduced into the Ugba was conducted. A total of Six LAB isolates designated with codes were obtained based on their catalase spot test reaction. zones of inhibition ranging from 13-20mm, 12- 18 mm and 10-19mm were obtained against Escherichia coli, Staphylococcus aureus and Candida albicians respectively. The LAB isolate code A1 with the Best Antimicrobial Activity was identified as Lactobacillus plantarum. The bacteriocin produces by Lactobacillus plantarum (A) was slightly stable at 40 and 60°C with a continuous decrease at 80 and 100°C for 30 mins but totally lost the activity at 121 °C for 15 min. The effect of pH on partially purified bacteriocin showed maximum activity against Escherichia coli, Staphylococcus auerus and Candida albicians. at pH 5.0 (18 mm ,17mm and 15mm respectively) and a continuous decrease as the pH increased from 6 to 9. The antimicrobial activity of bacteriocin was lost after treatment with proteolytic enzyme: trypsin and pepsin. This study show that Lactobacillus plantarum isolated from ugba has great potential for exploitation in food safety and preservation as a result of its bacteriocin content. Thus this locally fermented food plays a dual role of protection from pathogenic agents as well as serving as a functional food. It is therefore recommended that everybody should begin to consume ugba on a regular basis.