Comparative Studies on the Biosurfactant Production Capacity of Bacillus Subtilis and Pseudomonas Aeruginosa Using Engine Oil and Diesel Respectively as Substrate

The study was carried out to compare the the production capabilities and the biosurfactant activity of the bacteria, Bacillus subtilis and Pseudomonas aeruginosa using engine oil and diesel as the substrates respectively. The test organisms were isolated from engine oil contaminated soil as in the case of the Bacillus subtilis, which was collected from an automobile workshop in Samaru, Zaria and hydrocarboncontaminated water in the case of the Pseudomonas aeruginosa. The medium used for the experiment was a mineral medium supplemented with 2% engine oil and 2% diesel as the sole source of carbon and energy for Bacillus subtilis and Pseudomonas aeruginosa respectively. Production of biosurfactant was assayed by monitoring the increase in cell concentration, biosurfactant concentration, emulsification index and decrease in surface tension. Highest level of cell concentration and biosurfactant concentration (3.3 x 108 CFU/ml and 0.0106mg/ml respectively) were obtained at 144 h for the Pseudomonas aeruginosa using diesel as source of carbon and energy while the highest level of cell concentration and biosurfactant concentration (3.2 x 108 CFU/ml and 0.0096mg/ml respectively) were obtained at 120hrs for the Bacillus subtilis using engine oil as source of carbon and energy. The research show that Pseudomonas aeruginosa using diesel as the sole source of carbon and energy is better for the production of biosurfactant than Bacillus subtilis using engine oil as the sole source of carbon and energy.Key words: Biosurfactant, engine oil, diesel, Pseudomonas aeruginosa, Bacillus subtilis

Prevalence of Escherichia coli some public water sources in Gusau Municipal, North Western Nigeria

This study investigated the presence of Escherichia coli from some public water sources in Gusau municipal, north- western Nigeria. This was done by determining the total coliform counts and the presence of Escherichia coli and its antibiotic susceptibility profile. A total of 180 well 60 tap and 60 packaged water samples were obtained from Gusau municipal on weekly basis over a period of seven month (August, 2006-Feb, 2007) covering part of rainy and dry seasons. Standard procedures were used for the identification of Escherichia coli and for estimating total coliform counts. All samples had coliform counts higher than the international standard recommended by the World Health Organization. Results of biochemical analysis of the samples showed that out of 63 confirmed Escherichia coli isolated, 41 (45.5%) were from well water, tap water had 14 (23.3%) while packaged water had 8(13.3%).The susceptibility profile of the isolates to nine antimicrobial agents indicated that majority of the isolates were highly susceptible to Chloramphenicol, Gentamycin, Perrfloxacin, Tarivid, Augmentin, Streptomycin, Sparfloxacin, and Ciprofloxacin, moderate susceptibility to Septrin and resistant to Amoxacilin were observed. None of the water samples met the WHO standards for drinking water and thus pose a serious health risk to its consumers and users if not properly treated. Key words: Bacteriological quality, Escherichia coli, Prevalence, susceptibility profile, public water sources, Gusau