Research Articles Biological Sciences

Permanent URI for this collection

https://repository.elizadeuniversity.edu.ng/handle/20.500.12398/15

Browse

Now showing 1 - 20 of 297

Survival of Escherichia Coli in Lagos Lagoon
(1981) Amund, Olukayode O.; Ekundayo, J. A.; Ogunsanya, C. O.; Akpata, T. V. I.
There was a gradual decrease in the population of Escherichia coli incubated in autoclaved and unautoclaved (raw) water samples obtained from three different sampling stations of the Lagos lagoon. The survival period of the bacterium was generally shorter in the unautoclaved than in the autoclaved water sample; and also varied with the season. In November, 1976, the survival periods in unautoclaved (raw) samples were 6 and 8 days respectively; while in February, 1977 they were 12 days for all three water samples. For the autoclaved water samples the survival periods in November 1976 were 12 and 14 days; while in February, 1977 they were 22, 24 and 32 days. The survival period was also affected by seasonal variations in some physic-chemical parameters of the lagoon.
Increased L-ornithine production by an arg mutant of Acinetobacter lwoffi
(Springer-Verlag, 1983-07-01) Amund, Olukayode O.; Mackinnon, G.; Higgins, I. J.
The metabolic production of L-ornithine by an arg mutant of Acinetobacter Iwoffi using n-hexadecane as sole carbon source was studied. Time course experiments under optimised conditions showed that L-ornithine production was growth related, with maximum concentrations (10.5gl-1) accumulating in the late exponential phase of growth.
Observations on the Degradation of Crude Mineral Oil by an Estuarine Microbial Community.
(The Nigerian Society for Microbiology, 1984) Amund, Olukayode O.
An oil-degrading bacterium identified as Acinetobacter lwoffi. S2 was isolated by enrichment on the North Sea Forties oil from a water sample collected from the Medway estuary, Kent, England. This organism metabolises a wide range of long-chain n-alkanes (C8–C28) through the corresponding n-alkan-1-ols and n-alkanoic acids. A mixed microbial population was shown to effect a more extensive degradation of crude oil than single species. Simultaneous growth of five estuarine bacterial isolates on crude oil resulted in the synthesis of novel alkanes of higher molecular weights than those originally founds in the crude oil sample. Results of further investigation however, showed that the novel alkane synthesis could be attributed to the synergistic relationship in the estuarine microbial community.
The Degradation of 1-Phenylalkanes by an Oil-Degrading Strain of Alinetobacter Iwoffi
(Kluwer Academic Publishers, 1985-01-01) Amund, Olukayode O.; Higgins, I. J.
An oil-degrading bacterium identified as Acinetobacter lwoffi was isolated by elective culture on North Sea Forties crude oil from an activated sludge sample. It grew on a wide range of n-alkanes (C12 – C28) and 1 –phenylalkanes, including 1-pheny1dodecane, 1-pheny1tridecane and 1-pheny1tetradecane. The organism degraded 1-pheny1dodecane to phenylacetic acid which was further metabolized via homogentisic acid, whilst 1-phenyltridecane was transformed to trans-cin-namic and 3-pheny1propionic acid which were not further metabolized. Evidence is presented for a relationship between aromatic amino acid catabolism and 1-pheny1dodecane degradation in this organism.
A study of bacteria from the digestive system of two advanced termites (Isoptera, Termitidae) in Nigeria
(1986) Amund, Olukayode O.; Yakubu, O. S.; Malaka, S. L. O.
1. The total heterotrophic counts of bacteria present in the digestive system of Macrotermes bellicosus Smeathman and Amitermes evuncifer Silvestri were carried out. 2. The populations of bacteria in the guts of workers were generally higher than in those of soldiers. 3. A total of nineteen bacterial strains belonging to four main genera, namely Cytophaga, Micrococcus, Bacillus and Sarcina were isolated; six of these organisms were capable of producing cellulose-digesting enzymes. 4. The possible role of these cellulolytic bacteria in termite nutrition was discussed.
Occurence and Characteristics of HydroCarbon-Utilizing Bacteria in Nigerian Soils Contaminated with Spent Motor Oil
(1987) Amund, Olukayode O.; Adebowale, A. A.; Ugoji, E. O.
Soil samples were collected from four different oil-contaminated sites in Lagos, Nigeria, Enrichment of soil samples in a mineral salts medium containing SAE 40 motor oil as carbon source resulted in the isolation of eleven bacterial species. These organisms were identified as species of Corynebacterium, Acinetobacter, Pseudomonas, Bacillus, Arthrobacter, Gemella, Flavobacterium and Micrococcus. Substrate specificity tests showed that the organisms could utilize long chain n-alkanes including dodecane, tetradecane and hexadecane. Some species grew on some aromatic hydrocarbons, such as naphthalene, anthracene and phenanthrene. However, all the isolates grew on crude oil as well as motor oil. The growth of a Pseudomonas sp on motor oil resulted in the extensive degradation of the oil and in the synthesis of a new compound.
Extracellular Amylase Production by Cassava-Fermenting Bacteria
(Springer-Verlag, 1987-07-01) Amund, Olukayode O.; gunsina, Olusola A. O.
Fermentation of cassava tubers was accompanied by a gradual decrease in pH, increased amylase activity in the steep liquor, and increased microbial load and lactic acid concentration. Amylase-producing bacterial strains associated with cassava fermentation were isolated and identified as Bacillus subtilis, Bacillus licheniformis and Bacillus cereus. The pH optima for the partially purified enzymes of these organisms were 7.0, 5.5 and 7.5, whilst their temperature optima were 30, 37 and 80 oC. There was no significant difference in amylase activities when starch, dextrin, amylopectin, glucose and maltose were used as growth substrates.
Microbial Rotting and Preservation of Banana Fruits (Musa Sapientum L.) in Nigeria
(The faculty press, Cambridge, 1990) Okonkvvo, Ussana N.; Amund, Olukayode O.; Ogunsanya, Caroline O.
The bacterial and fungal pathogens associated with the watery rot of banana fruits were isolated and identified. The bacterial pathogens were Pediococcus sp., Propionibacterium sp. and Pseudomonas aeruginosa. The fungal pathogens which also showed cellulolytic activities were Botryodiplodia theobromae, Aspergillus niger and Rhizopus sp. These organisms caused rot at room temperature but were unable to cause rot at 5 oC and 10 oC. Banana fruit rot was generally prevented at relative humidities of 10, 50, 80, 90 and 100 %, except that Botryodiplodia theobromae caused rot at 10, 50, and 80% RH. Microbial infection of healthy fruit resulted in a depletion of the total carbohydrate, crude protein, reducing sugar, free fatty acid and ascorbic acid contents. There was an increase in the total lipid and moisture contents of spoilt fruits. Preservation of banana fruits with fungicides and chemical preservatives was investigated. The use of fungicidal wax emulsion was observed to delay fruit ripening and prevented moisture loss thereby controlling the onset of rot.
Purification and properties of a neutral protease produced by Lactobacillus brevis
(Elsevier, 1990-03-01) Amund, Olukayode O.; Omidiji, O.
A proteolytic enzyme was produced by a strain of Lactobacillus brevis isolated from an oriental beverage. The enzyme was extracted and purified 50-fold by gel filtration and ion-exchange chromatography. The optimum pH for the enzyme was 7.0, the optimum temperature 35°C and the molecular weight 34,674 Da. Furthermore, the enzyme was stimulated by cations including Ca2+, Mg2+, Na+ and K+ and inhibited by Zn2+ and Co2+ ions. Other inhibitors were EDTA, ascorbic acid and citric acid. The enzyme is probably a neutral metalloprotease.
Biodegradation of Petroleum Hydrocarbons Under Tropical Estuarine Conditions
(Kluwer Academic Publishers, 1990-09) Amund, Olukayode O.; Igiri, C. O.
The physic-chemical parameters of water samples collected from three points in the Lagos lagoon were studied for 12 months. Salinity varied seasonally but the temperature, pH, dissolved O2, conductivity, NO3 and HPO42- concentrations were relatively constant. There was a direct proportionality between the population density of hydrocarbon-utilizing bacteria and the oil content of water samples. Twelve hydrocarbon-utilizing bacteria were isolated by selective enrichment and characterized as species of Pseudomonas, Alcaligenes, Acinetobacter and Bacillus. The organisms grew mainly on long-chain aliphatic hydrocarbons. Laboratory and field biodegradation studies showed both quantitative and qualitative changes in the hydrocarbon content of crude oil due to microbial degradative activities and a faster rate of oil depletion from the Lagos lagoon during the rainy season. The results obtained could offer a predictive model for estimating the rate of disappearance of petroleum hydrocarbons from the tropical estuarine environment.
Purification and Properties of a Neutral Protease Produced by Lactobaccillus Brevis
(Kluwer Academic Publishers, 1990-09-01) Ilori, Matthew O.; Amund, Olukayode O.; Omidiji, O.
An extracellular glucose-forming amylase was produced by Lactobacillus brevis isolated from ‘Kagasok tea’. The enzyme was purified 70-fold and had optimal activity at 55 oC and pH 6.5. Its Km value for starch was 0.27 mg ml-1 and its M, was approx. 75,900 Da. The activity of the enzyme was enhanced by Ca2+, Mg2+, Na+ or K+ and inhibited by EDTA, KCN, citric acid and L-cysteine.
Occurrence and Distribution of Sulphate-Reducing Bacteria in a Polluted Lagoon
(The faculty press, Cambridge, 1991) Esiobu, N.; Amund, Olukayode O.; Fakile, O. O.; Popoola, O. H.
The presence and distribution of sulphate-reducing bacteria (SRB) in the sediment and water from four strategic points on the Lagos Lagoon were assessed using the most probable number technique. All the samples were positive for the dissimilatory sulphate reducers. The relative occurrence varied markedly with the site and pollution status. The least polluted end of the lagoon recorded the lowest number of SRB in both sediment (4.23x102 SRB/ml) and water (28 SRB/ml) while the most polluted site receiving sewage and domestic wastes harboured numbers as high as 5.71x103 and 7.6x104 SRB/ml for water and sediment sasmples, respectively. The occurrence of sulphate-reducing bacteria in such numbers indicated that this environment favoured biocorrosion of buried and immersed metals. The active involvement of these organisms in the syngenesis of sulphur, metallic sulphides and the general biodegradation of pollutants in this ecosystem is discussed.
Effect of Viscosity on the biodegradability of Automotive Lubricating Oils
(Elsevier, 1991-08-01) Amund, Olukayode O.; Adebiyi, A. G.
Hydrocarbon-utilizing bacteria were isolated by enrichment from water samples collected from the Lagos lagoon and identified as species of Achromobacter, Acinetobacter, Alcaligenes, Arthrobacter, Bacillus, Flavobacterium, Micrococcus and Pseudomonas. The growth potentials of these isolates were evaluated using lubricating oils of different viscosities as substrates. All the organisms grew without lag on oils of low viscosity while they grew with pronounced lag phases on the highly viscous lubricating oil (bright stock). The biodeterioration potential of lubricating oils therefore appears to be closely related to their viscosities.
Hydrocarbon Degradation Potentials of Yeast Isolates from a Polluted Lagoon
(1993) Amund, Olukayode O.; Nwokoye, N.
The population counts of heterotrophic and hydrocarbon-utilising yeasts were monitored at six sampling stations in the Lagos lagoon over a four-week period. Although the population counts were relatively constant in each locality, the highest counts occurred in areas heavily polluted by domestic and industrial effluents. A total of thirty-two hydrocarbon-degrading yeasts were isolated from water at the sampling stations using n-hexadecane as sole carbon source. The isolates were identified as belonging to the genera Candida (25 strains), Endomycopsis (4 strains) and Schizosaccharomyces (3 strains). All the organisms grew on long-chain n-alkane, kerosene, diesel oil and crude oil but failed to grow on short-chain n-alkane, aromatic and alicyclic hydrocarbons. Measurement of growth attributes of the isolates using n-hexadecane, diesel oil oil and crude oil as substrates showed that the Candida species were better utilizers of hydrocarbon substrates relative to Endomycopsis and Schizosaccharomyces species.
Effects of waste engine oil spillage on soil physico-chemical and microbiological properties
(1993) Amund, Olukayode O.; Omole, C. A.; Esiobu, N.; Ugoji, E. O.
Changes in physic-chemical and microbial properties of soils contaminated with waste motor oil were monitored over a 24 week period. Oil application to soils resulted in a decrease in moisture content but brought about increase in organic matter, total nitrogen and available phosphorus contents. There was an initial decrease in microbial counts followed by a subsequent increase in population levels after four weeks. Microbial species diversity was however reduced in oil-contaminated sites relative to the control sites. Hydrocarbon-utilizing bacteria isolated from the experimental sites were identified as Pseudomonas, Acinetobacter, Alcaligenes, Flavobacterium and Corynebacterium. The organisms grew on long-chain n-alkanes, crude oil and fresh engine oil while a few species grew on aromatic hydrocarbons. Laboratory biodegradation studies of fresh engine oil using strains of Pseudomonas, Acinetobacter, and Corynebacterium showed a progressive decrease in oil concentration and pH of the medium due to the production of acidic metabolites.
Microbial Degradation of Four Nigerian Crude Oils in an Estuarine Microcosm.
(Blackwell Publishing Ltd, 1993-03) Amund, Olukayode O.; Akangbou, T. S.
Four Nigerian crude oils (Bonny Light, Bonny Medium, Escravos Light and Forcados Blend) that differ substantially in fractional composition were exposed to the Lagos Lagoon waters in microcosm experiments with oil-impregnated membrane filters. Changes in microbial numbers on the membranes and in the residual oil concentration showed a relationship between the fractional composition and the biodegradation rates of the oils, with the lighter oils disappearing more rapidly. After 10 weeks exposure in the lagoon, only 15 % (w/w) of the Bonny Light crude remained on the filters as compared with 20, 32 and 45 % (w/w) for Escravos Light, Bonny Medium and Forcados Blend respectively. The hydrocarbon-utilizing microbial colonizers of the oil-impregnated membranes were Micrococcus, Bacillus, Pseudomonas, Flavobacterium, Alcaligenes and Aspergillus niger.
Genetic Transfer of Auxotrophic Markers in Hydrocarbon-Utilizing Strains of Acinetobacter Lwoffi
(1996) Amund, Olukayode O.
Conjugal transfer of chromosomal genes was shown to occur in oil-degrading strains of Acinetobacter lwoffi. High co-inheritance frequencies of auxotrophic makers inconjugation experiments suggested linkage relationships amongst the, trp and arg loci. The significance of gene transfer in Acinetobacter species was discussed.
Utilization and degradation of an ester-based synthetic lubricant by Acinetobacter lwoffi
(Kluwer Academic Publishers, 1996-04-01) Amund, Olukayode O.
An oil-degrading bacterium, Acinetobacter lwoffi, isolated by elective culture from the Medway estuary, utilized an ester-based synthetic lubricating oil EMKARATE DE 155 as sole carbon and energy source. Analysis of culture supernatants by gas chromatography showed the accumulation of a nondegradable metabolite 1,1,1 Tris (hydroxymethyl) propane in addition to two metabolizable fatty acids, octanoic and decanoic acids as products of the synthetic oil degradation. Esterase activities were subsequently demonstrated in oil and acetate-grown cells. The synthetic oil therefore appears to be partially biodegradable in the environment.
Effect of carbon and nitrogen sources on glucoamylase production inLactobacillus brevis
(springer, 1996-04-11) Ilori, Matthew O.; Amund, Olukayode O.; Omidiji, O.
A strain of Lactobacillus brevis produced extracellular glucoamylase. Induction of the glucoamylase occurred when saccharides such starch, dextrin, maltose, mannitol and sucrose were employed as sole carbon sources. Synthesis of the amylase also occurred when soybean extract and peptone were used as sole nitrogen sources. The organism could be employed as a starter culture for local food fermentation.
Production of Amylase in a Corn Steep Liquor-Soya Bean Meal Medium by a Strain of Baccillus Stearothermophilus
(The faculty press, Cambridge, 1997) Omidiji, O.; Amund, Olukayode O.; Braimoh, A. A.; Ilori, Matthew O.
Corn grains (Zea mays, yellow variety) were steeped in water for 10 days and parameters such as pH, protein, amino acids, lipid, soluble starch and reducing sugar content were measured at 2 day intervals in the steep liquor. The pH decreased from 7.0 to 5.4 during the steeping period. The protein content ranged between 1.25 and 11.25 mg/ml; lipid content ranged between 0.3 and 3.2 mg/ml. The soluble starch concentration increased from 212 to 530 mg/ml, and the reducing sugar concentration reduced from 2.54 to 1.13 mg/ml. A fermentation medium was compounded from 2-day old liquor to cultivate an amylolytic strain of Bacillus stearothemophilus. Peak production of amylase occurred at 240 h while the highest cell density occurred at 144 h. Various concentrations of soluble starch (0.5-5%, w/v) and soya bean meal (0.1-0.5 %, v/v) were used in cultivating the organism. The highest amylase activity was recorded with 2 % (w/v) starch, while 0.5 % (v/v) of soya bean meal supported the greatest growth. The medium could be exploited for industrial amylase production.

Browse

Browsing Research Articles Biological Sciences by Issue Date

Results Per Page

Sort Options