A Comparative Study of Biosurfactant Synthesis by Pseudomonas aeruginosa Isolated from Clinical and Environmental Samples

Evaluation of emulsifying activities indicates that biosurfactants were produced by an environmental (strain EP1) and a clinical (strain CP1) species of Pseudomonas aeruginosa. During growth on hydrocarbons, the organisms produced biosurfactants. Both strains grew luxuriantly on motor oil and readily synthesized abundant surfactants at the expense of easily metabolizable substrates. During a 12-day cultivation on motor oil, the organisms produced growth-associated extracellular surfactants with emulsification activities of 71 and 38% for EP1 and CP1, respectively. The generation times obtained for EP1 and CP1 were 1.74 and 2.66 days. The biosurfactants that could not be secreted on glucose were partially purified and putatively identified as rhamnolipids. The surface-active compounds present high emulsification activity and stability in the pH range of 3.0–10.0, temperature range of 4°C–100°C, and salinity range of 16–44% and are capable of stabilizing oil-in-water emulsions with several hydrocarbons. Typical emulsions produced were stable for several weeks. The results also showed that the biosurfactants were able to remove a significant amount of crude oil from contaminated soil; for instance, strain EP1 surfactant removed 54%, CP1 41%, detergent 42%, and water 30%. The rhamnolipids from these strains represent a new class of biosurfactants that have potential for use in a variety of biotechnological and industrial applications where extremes of pH, thermal, and saline conditions would have little or no effect on activity

Biodegradation of p-Chloroaniline by Bacteria Isolated from Contaminated Sites

Enrichment of water from a contaminated site in a textile industry in Ikeja resulted in the isolation of two bacteria belonging to the genera Alcaligenes and Cellulomonas. These bacteria were able to mineralize para-chloroaniline (p-chloroaniline). Time course degradation of p-chloroaniline using pure cultures of these organisms showed that p-chloroaniline supported the growth of these isolates. An initial increase in cell densities of 7.50-9.46 cfu/mL was recorded from day 0-9th day for Cellulomonas sp. while for Alcaligenes denitrificans it was 7.20-9.40 cfu/mL. After day 9, a decrease in population occurred, indicating non-availability of nutrients or toxicity of the medium. Simultaneously, a decrease in the pH, indicative of increased acidity of the medium, was also observed from the first day. The result of the GC analysis of the pure isolates on p-chloroaniline shows that 86.5% of the p-chloroaniline was degraded by the Cellulomonas sp. while 81.2% was degraded by the A. denitrificans in 30 days. These bacterial isolates utilized other hydrocarbons such as pyrene, anthracene, crude oil and chlorobenzoates as sole source of carbon and energy but not phenanthrene, naphthalene and biphenyl. The two isolates tolerated NaCl concentration of up to 5%

A review of ophthalmic registries in Africa – The shortage and importance

BACKGROUND: Clinical registries systematically collect standardized information for pre-defined purposes on patients with a particular condition of interest. The characteristics and quantity of ophthalmic registries in Africa are unclear.This study aimed to quantify ophthalmic clinical registries in African countries from published literature, and to supply an overview of the features and study outcomes of these registries. METHODS: A systematic search of the EMBASE, PubMed, and Web of Science databases was conducted to find ophthalmology clinical registries in Africa without time and language limitations. Relevant data elements about registry characteristics, nature, methodology, and outcomes were extracted for each individual registry identified. RESULTS: Six clinical eye registries were found with no substantial growth over time. The most common condition captured is ocular tumors (n=3), of which two were retinoblastoma-specific registries. Five of them were focused on retinal diseases and one on blindness and low vision. None addressed cataracts and glaucoma. A third of the registries originated outside Africa, and one was multinational. Only three African countries produced a registry data set, with South Africa having the majority of the registries (n=3), followed by Egypt (n=2), and Ghana (n=1). Ophthalmic registries in Africa are used to study the epidemiologic features of ocular diseases, treatment outcomes, and genetic analysis. CONCLUSIONS: The potential for clinical eye registries has not been adequately harnessed in Africa, as only a few ophthalmic registries exist. Findings from this study may help inform the planning and implementation of future ophthalmic registries and suggest focus areas that have not received due attention

Efficacy of intervention strategies for bioremediation of crude oil in polluted soil microcosm

Crude oil, though not manmade but largely manipulated by man to provide different oil-based products has become a major source of environmental pollution. This menace on land do contribute to the retardation of vegetation growth and human health hazards, while in water it may be toxic to aquatic animals. The search for the solution to ameliorate the seemingly unending pollution and its side effects necessitated the evaluation on the effect of bioaugmentation, biostimulation and natural attenuation of crude oil pollution in soil microcosms. The bacterial species selected for this study (Bacillus thuringensis strain LG32 and Burkolderia pseudomallei strain A81) were preliminarily identified using the conventional biochemical tests and further identification was carried out using the API kit. The results of the study carried out over a period of five weeks indicated that there was a marked reduction in the available phosphorous and potassium in the bioaugmented and biostimulated soils compared with that of the control. The mean values for total viable counts (TVC) of population of hydrocarbon utilizing bacteria (HUB) was higher in the bioaugmented soil ranged (LG32=6.0-7.5log10cfu g-1 ; A81=5.5- 7.5log10cfug-1 ; LG32+A81=6.0-7.5log10cfug-1 ) compared with that of the control (6.0-6.2log10cfug-1 ). When bioaugmentation was combined with biostimulation, the soil had higher counts of HUB (6.0-9.0log10cfug-1 ) and HUF (3.5-6.5log10cfug-1) compared to bioaugmentation without stimulation (HUB: 6.0-7.5; HUF: 3.5-5.5). The GC result indicated that by day 35, 96.92% of the aliphatic and aromatic components have been degraded in the augmented soil, higher than the natural attenuation control

Pyrene-degradation Potentials of Pseudomonas Species Isolated from Polluted Soils

Three Pseudomonas species isolated from oil polluted soil in Lagos, Nigeria were studied for their pyrene degradation potentials. These isolates exhibited broad substrate specificities for hydrocarbon substrates including polycyclic aromatic hydrocarbons, petroleum fractions and chlorobenzoates. All three isolates tolerated salt concentrations of more than 3%. They resisted ampicillin, cenfuroxime, but susceptible to ofloxacin and ciprofloxacin. Pseudomonas sp. Strain LPl exhibited growth rates and pyrene degradation rates of 0.018 h-1 and 0.111 mg l-1 h-1 respectively, while P. aeruginosa strains LP5 and LP6 had corresponding values of 0.024, 0.082 and 0.017, 0.067 respectively. The overall respective percentage removal of pyrene obtained for strains LPl had the highest uptake rate. Strains LPl, LP5, and LP6 also used the ortho-cleavage pathway. Enzyme study confirmed activity of catechol 1,2-dioxygenase in all with values 0.6823,0.9199, and 0.8344 umol min-1 mg-1 respectively for LP1, LP3 and LP6. To the best of our knowledge, ours is the first report of pyrene-degraders from the sub-Saharan African environment