F. I. OKOLAFOR

This Research focused on the isolation and characterization of bacteriocin produced by Lactobacillus sp. isolated from nunu, a traditionally fermented milk beverage, and its antimicrobial effect against Escherichia coli. Samples of nunu were collected from local markets in Oredo Local Government Area, Edo State, and analyzed in the Department of Science Laboratory Technology Microbiology Laboratory. The isolate was cultured on de Man, Rogosa, and Sharpe (MRS) agar and identified through morphological and biochemical characterization. The isolates were Gram-positive, catalase-negative, and capable of fermenting lactose, galactose, and fructose, confirming them as Lactobacillus sp.. Bacteriocin production was screened using the agar well diffusion method, with E. coli as the test organism. Clear zones of inhibition (ZOI) were observed, indicating the production of antimicrobial compounds. The bacteriocin extract was neutralized to pH 7.41 to eliminate the effects of organic acids and partially purified using ammonium sulfate precipitation (60% saturation) followed by dialysis. The purified extract was further characterized using High- Performance Liquid Chromatography (HPLC), which revealed distinct peaks corresponding to bacteriocin fractions. The antimicrobial assay showed that the bacteriocin exhibited inhibitory activity against E. coli, suggesting its potential as a natural bio preservative in perishable food products such as tomato. The findings indicate that bacteriocin from Lactobacillus sp. in nunu can serve as safe and effective alternatives to chemical preservatives and synthetic antibiotics, thereby contributing to improved food safety and public health.

This study investigates the antimicrobial and antioxidant properties of ethanol and aqueous extracts of Curcuma longa (turmeric) rhizomes against clinical nasal isolates. The research aims to evaluate the efficacy of these extracts in combating microbial infections and their potential as natural antioxidants. The chemical composition of the extracts was characterized using Gas Chromatography-Mass Spectrometry (GC-MS), revealing a diverse array of bioactive compounds, including terpenes, fatty acids, phenolic compounds, and sterols. Antimicrobial activity was assessed using the broth dilution method, while antioxidant potential was determined through the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. The results indicate that the ethanolic extract exhibited significant antimicrobial activity against nasal isolates, including Micrococcus species, Moraxella catarrhalis, and Streptococci species. Additionally, the aqueous extract demonstrated strong antioxidant properties, with a linear increase in activity correlating with concentration. The findings suggest that Curcuma longa extracts, particularly the ethanolic extract, hold promise as natural antimicrobial agents, while the aqueous extract shows potential as a potent antioxidant. This study underscores the therapeutic potential of Curcuma longa in addressing antibiotic resistance and oxidative stress-related conditions, providing a scientific basis for its traditional use in medicine and its application in modern healthcare