Partial Purification, Characterization and Application of Bacteriocin from Bacteria Isolated Parkia biglobosa Seeds

Staff PublicationBacteriocins are proteinaceous toxins produced by bacteria to inhibit the growth of similar or closely related bacterial strains. Fermented Parkia biglobosa seeds (African locust bean) were screened for bacteriocin-producing lactic acid bacteria (LAB) with the characterization of putative bacteriocins. Bacteriocin-producing lactic acid bacteria (LAB) were identified by 16s rDNA sequencing. Molecular sizes of the bacteriocins were determined using the tricine-sodium dodecyl sulphate-polyacrylamide gel electrophoresis (tricine-SDS–PAGE) and effects of enzymes, pH, detergents and temperature on bacteriocin activity investigated, using standard procedures. Bacteriocins production and activities were measured by spectrophotometric analysis. Statistical analysis was carried out using student t-test and Analyses of Variance. Bacteriocigenic LAB isolated were Lactobacillus plantarum Z1116, Enterococcus faecium AU02 and Leuconostoc lactis PKT0003. They inhibited the growth of both Gram-positive and Gram-negative bacteria. The sizes of bacteriocins Z1116, AU02 and PKT0003 were 3.2 kDa, 10 kDa and 10 kDa, respectively. The synergistic effects of characterized bacteriocins and rifampicin tested on organisms showed significant differences (P < 0.05), as compared with the effects of only one of the two. The antimicrobial activity of the three bacteriocins was deactivated after treatment of the cell-free supernatants with proteinase K, papain, pepsin and trypsin. Parkia biglobosa seeds are, therefore, rich in LAB bacteriocins which could be explored. The biosynthetic mechanisms of LAB bacteriocins could be employed in food safety and security, preservation, peptide design, infection control and pharmacotherapy. This should help in the control of undesirable bacteria and in designing more potent and selective antimicrobial peptides

Optimization of oil extraction from Pitanga (Eugenia Uniflora L) leaves using Simplex Centroid Design (SCD)

Simplex centroid design (SCD) was employed to optimize the mixing of petroleum ether, n-hexane, methanol and ethanol for the extraction of oil (PLO) from Pitanga (Eugenia uniflora L.) leaves, via Soxhlet extraction. The highest yield (54%) of Pitanga leaf oil (PLO) was obtained with 100% ethanol and the lowest yield (16%) from the mixture of methanol (33.3%)/hexane (33.3%)/ethanol (33.3%). The coefficient of determination (R2) of the model equation obtained was 0.91, while the adjusted R2 and predicted R2 were 0.8729 and 0.951, respectively. The saponification value (S.V.), iodine value, acid value and free fatty acid (FFA) are 35.34 mgKOH/g, 72.97 mgI2/g oil, 32.41 and 16.30 mgKOH/g, respectively