ABSTRACT
Aims@#This study was aimed to isolate and characterize biosurfactant producing bacteria from Mile 2 and Ologe Lagoon which are sinks for domestic and industrial waste waters and potential source of value added bioresources such as biosurfactants, hydrocarbon degraders and organisms with potential for biotechnological applications.@*Methodology and results@#Physicochemical parameters of the two lagoon waters were analyzed using standard procedures. Bacteria were isolated using enrichment techniques on 1% Escravos light crude oil, palm oil and groundnut oil on mineral salt medium (MSM). Biosurfactant production by the isolates was assayed by hemolytic activity, oil spread test, blue agar test and emulsification activity. Isolates were identified using their colony morphologies and biochemical characteristics, while the antibiotic susceptibility of the isolates was determined using multidisc. The physicochemistry of the lagoon water showed high nitrate content of 15.7 mg/L and 19.6 mg/L for Mile 2 and Ologe Lagoon, respectively. Total hydrocarbon content (THC) of both lagoon waters was low, with values 0.53 mg/L for Mile 2 Lagoon and 0.44 mg/L for Ologe Lagoon. The predominant genera of bacteria identified include Micrococcus, Bacillus, Pseudomonas, Acinetobacter, Stomatococcus and Moraxella. A total of 23 bacterial isolates were tested for hemolytic activity, of which 13 showed β-hemolysis which is presumptive for biosurfactant production, 5 showed α-hemolysis and the remaining 5 exhibited γ-hemolysis. Majority of the isolates were positive for oil spread assay and blue agar test (19) indicating production of anionic biosurfactant. The isolates showed good emulsification activity; AGG3 (67.7%), AGG1 (62.3%), AGG2 (60%), AGG4 (60%), MTP2 (56%), AGC4 (54%) and the least emulsification value of 23.3% for strain AGP1. Most of the isolates were susceptible to ciprofloxacin, perfloxacin and showed resistance to septrin and erythromycin.@*Conclusion, significance and impact of study@#This study showed that Mile 2 and Ologe Lagoon are a potential source of biosurfactant producers with diverse emulsification properties and prospective industrial applications. This would have implication for economic empowerment, as well as sustainable and environmentally friendly clean-up technology in both locally and globally.
Subject(s)
Surface-Active Agents , NigeriaABSTRACT
Aims@#Water is described as safe and wholesome when it is free from pathogenic microorganisms and chemical substances that are hazardous to human health. This study aimed to investigate the microbial quality of water used for drinking, cooking, bathing and other purposes at universities in Nigeria.@*Methodology and results@#Water samples were collected from forty-four storage tanks across four selected universities. Total viable bacteria in the water samples were cultivated using the plate count agar. The isolation of total coliform and Escherichia coli were carried out on Harlequin™ E. coli/coliform agar (HA) medium, while media-faecal coliform was used for faecal coliform employing the membrane filtration technique. Physicochemical parameters such as alkalinity, pH, total alkalinity, total dissolved solid, total suspended solid, electrical conductivity, total hardness, fluoride and chloride ion concentrations, were evaluated in accordance with standard procedures. Data were compared statistically using MedCalc statistical software. Considering the heterotrophic bacterial counts, all water samples were unsatisfactory. For the total coliform counts, 50% of samples were satisfactory but suspicious, while remaining 50% were unsatisfactory. Faecal coliforms results showed that 50% of samples gave excellent quality, 25% showed satisfactory but suspicious quality, while 25% showed unsatisfactory result. There were no significant differences in the total viable, total coliform and E. coli counts of water sampled from universities A and D (p>0.05). The predominant bacterial species was Pseudomonas aeruginosa (23.17%), while the least encountered was Salmonella typhimurium (2.44%). All physicochemical parameters tested were within the acceptable limit.@*Water samples were collected from forty-four storage tanks across four selected universities. Total viable bacteria in the water samples were cultivated using the plate count agar. The isolation of total coliform and Escherichia coli were carried out on Harlequin™ E. coli/coliform agar (HA) medium, while media-faecal coliform was used for faecal coliform employing the membrane filtration technique. Physicochemical parameters such as alkalinity, pH, total alkalinity, total dissolved solid, total suspended solid, electrical conductivity, total hardness, fluoride and chloride ion concentrations, were evaluated in accordance with standard procedures. Data were compared statistically using MedCalc statistical software. Considering the heterotrophic bacterial counts, all water samples were unsatisfactory. For the total coliform counts, 50% of samples were satisfactory but suspicious, while remaining 50% were unsatisfactory. Faecal coliforms results showed that 50% of samples gave excellent quality, 25% showed satisfactory but suspicious quality, while 25% showed unsatisfactory result. There were no significant differences in the total viable, total coliform and E. coli counts of water sampled from universities A and D (p>0.05). The predominant bacterial species was Pseudomonas aeruginosa (23.17%), while the least encountered was Salmonella typhimurium (2.44%). All physicochemical parameters tested were within the acceptable limit.@#This study revealed that the water used by students of studied universities was contaminated with potential bacterial pathogens. However, all physicochemical parameters tested were within the permissible standard limits and satisfied the requirements for domestic utility.