Potential for nitrogen fixation and biomass production in Panicum maximum

Investigations were carried out to ascertain the relationship between the potential for biomass production and nitrogenfixation in tbe rhizosphere of Panicum maximum. With a dry matter production of 1.85 ± lAO and 0048 ± 0.33 kgm-2, a positive correlation (1=0.62) was found to exist between the numbers of nitrogen-fixing bacteria in the rhizosphere of this grass and total dry matter production. The influence of concentrations of organic carbon substrates in roots/ rhizomes on total bacterial populations was also investigated. Results showed that increasing concentrations of organic acids, reducing sugars and miscellaneous soluble carbohydrates at naturally-occurring levels were accompanied by reductions in bacterial population. Aerobic nitrogen-fixing bacteria appeared to play the most dominant role as viable counts of these bacteria were about four times higher than those of their anaerobic counterparts. Azospirillum sp. contributed approximately 48 per cent of total aerobic counts and was found to be capabl e of growth under strictly anaerobic conditions where it constituted about 11 per cent of total counts. Panicum maximum was found to be capable of growth in soils of clay-loam, sandyclay or purely loam types with pH 5.0-5,9. The ammonium nitrogen levels in these soils were relatively low when compared to those of nitrite-nitrogen

Influence of divalent metal ions on degradation of dimethylsulphide by intact cells of Thiobacillus thioparus TK-m

Dimethylsulphide degradation by intact cells of Thiobacillus thioparus TK-m was stimulated by the addition of divalent metal ions (Ca2+ > Mg2+ > Mn2+). Mixtures of divalent ions were also found to be stimulatory with the exception of the Ca2+ + Mn2+ combination (Mg2+ + Mn2+ > Mg2+ + Ca2+ > Ca2+ + Mn2+)

Trends in vegetation cover changes in Bonny area of the Niger Delta

The main vegetation type in the area is the mangrove forest, which occupies most of the Niger Delta. The other vegetation type is the secondary (re-growth) vegetation that occupies a small area. The secondary vegetation is surrounded by the mangrove swamp forest; a two-layered vegetation. The one–layered forest has mangrove trees of 3-14 m high without undergrowth forming the only layer while the two-layered forest has a top layer made up of Rhizophora species (3-32 m high) depending on the height of trees at each site and a ground layer composed mainly of the fern Acrostichum aureum and seedlings of thetree species. There is a dearth of epiphytic bryophytes and lichens on the boles and branches of the trees. From satellite imageries of the area, it is evident that the landcover classes changed across the three epochs. The water class covered an area of 111.91km2 in 1986, 108.90km2 in 1998 and 103.41km2 in 2007. Mature forest (Forest I) occupies a total areaof 85.64km2 in 1986; decreased significantly to 59.68km2 in 1998 and 59.30km2 in 2007. This could be attributed to man-made and industrial activities. Secondary Forest (Forest II) covered 11.18km2 in 1986, but increased to 43.49km2 in 1998 and decreased to 23.30km2 in 2007. Urban/Industrial/Sand class had a steady increase across the epochs.This class which covered about 10.37km2 in 1986 increased to 14.73km2 in 1998, and 25.28km2 in 2007. This increment is attributed to influx of humans into the area as a result of increase in Oil and Gas industry activities. Mangrove class covered 87.02km2 in 1986 but increased to 95.86km2 in 1998 and 106.79km2 in 2007. Stressed Vegetation occupied 16.38km2 in 1986; this class type was only evident during that period. Sparse vegetation which covered an area of 5.23km in 1986; decreased slightly to 5.07km2 in 1998 but increased to 9.07 km2 in 2007. Overall, the most dramatic change recorded is with respect to the areal extent of Urban/Industrial/Sand which increased by about 42% between 1986 and 1998 and about 144% between 1986 and 2007. The area covered bymangrove forest consistently declined over all the epochs while the reverse was the case with respect to the area covered by sparse vegetation. The area covered by stressed vegetation in 1986 disappeared during other epochs

Response of microalgae from mud-flats to petroleum hydrocarbons in the presence of nitrogenous fertilizer effluents

Untreated industrial waste (effluent) from out-fall of the National fertilizer company of Nigeria (NAFCON) was found to be weakly alkaline with a pH of 7.8. Total dissolved solids and sulphate were relatively high with levels of 2052 and 1599 mg/l, respectively. Nitrogen as ammonia was high in comparison to nitrate nitrogen. Phosphate was also found to be low in concentration. Using indigenous microalgae and aeration, there was a reduction in nutrients; NH4 +, NO3 -, PO4 3- and SO4 2-. However, in the presence of the hydrocarbon, there was delayed nutrient uptake. The consequence of this response was the observed reductions in chlorophyll content, biomass, etc. There was however a quick recovery in theoiled systems

Uptake of crude petroleum hydrocarbons by mudflat bacteria exposed to nitrogenous fertilizer plant effluents

In the Niger delta, due to the large-scale exploration and exploitation of crude petroleum, hydrocarbon spills frequently occur. The adverse impacts of these occurrences have frequently been causes forconcerns in the area. However, in open estuarine environments, minor spills have short-term effects due to washout by stream water and increased microbial action. The microbial degradation of low levelspills is enhanced by the ‘continuous’ input of nitrogenous fertilizer (NPK) components. The ‘continuous’ input assists in mitigating dilution effects of the stream water thus increasing the availability of nutrients to the petroleum degrading microbes. The net result is the increased recovery potential of this estuarine environment in the event of pollution by crude oil hydrocarbons. Enumeration of viable aerobic heterotrophic bacteria showed that counts were higher in hydrocarbon amended nitrogenous fertilizer plant effluent than in the raw effluent. The higher counts were accompanied by a rapid decline in the level of crude petroleum in the amended effluent. The ability of aerobic heterotrophic mudflat bacteria to grow on three different refined petroleum products namely kerosine, diesel and engine oil was also studied. At the levels tested, there were no appreciable differences in growth patterns of petroleum utilizing bacteria in three refined products after 5 weeksincubation at ambient temperature

Factors affecting yeast growth and protein yield production from orange, plantain and banana wastes processing residues using Candida sp.

Agricultural residues rich in carbohydrates can be utilized in fermentation proceses to produce microbial protein which in turn can be used to upgrade both human and animal feeds. Studies to determine the factors influencing cell biomass production with Candida sp. using citrus fruit wastesshowed that the test strain was capable of meeting its amino acid requirements in culture when supplied with inorganic nitrogen sources. The organism was capable of growth at 37°C. Supplementation of media with 0 – 15% and 0 - 6% w/v combination of dextrose and ammonium nitrate,respectively, resulted in optimal growth at a pH of 4.6 (optimum pH) after 6.0 h. However, supplementation with phosphorus was not a critical condition for growth

Removal of crude petroleum hydrocarbons by heterotrophic bacteria in soils amended with nitrogenous fertilizer plant effluents

Nitrogenous fertilizer (NPK) plant effluents from NAFCON were used in amending plots of land experimentally polluted with crude oil. Counts of heterotrophic bacteria (THBC) and fungi (TF), and of petroleum utilizing bacteria (PUB) and fungi (PUF) were monitored during an 8 weeks period. Counts obtained showed that NPK served as a good supplement for the growth of the petroleum degrading/utilizing bacteria in oil-polluted soils. Crude oil disappearance in plots TSP ranged between 8.70 and 34.80% and 20.90 and 60.50% for TST; cumulative loss was 73.0%. The disappearance was influenced by the N/P ratio in the supplementing fertilizer effluent. A total of ten genera of petroleumdegraders were isolated, namely, Micrococcus, Pseudomonas, Acinetobacter, Proteus, Bacillus, Actinomyces, Corynebacterium, Enterobacter, Brevibacteria and Citrobacter. Crops grown on theexperimental plots at the end of the study period for soil recovery studies indicated good soil recovery

Degradation Of Methylmercaptan By Crude Enzyme Extracts Of Thiobacillus Thioparus TK-m

The biodegradation of methyl suphides by crude enzyme extracts of Thiobacillus Thioparus TK-m was investigated in this work. The data revealed that crude protein contents of enzyme extracts from cells of Thiobacillus thioparus TK-m was influenced by the saturation levels of the EDTA and ammonium sulphate solutions. For EDTA, error levels were 3, 5, 7 and 11.0 percent at 0.005, 0.1, 0.15 and 0.2 mM EDTA respectively. For ammonium sulphate, there was an increase in recovery of total activity at the 40 and 50 percent saturation levels (122.6 and 101.1 percent respectively) but a decrease at the 65% level (90.4%). Activity of crude enzyme extracts ranged between 0.095 and 1.28 \u3bcmolmin-1mg-1

Factors Influencing Degradation of Mercaptans by Thiobacillus Thioparus TK-m (1)

Degradation of methylmercaptans by Thiobacillus Thioparus TK-m was influenced by pH of the reaction medium. Ratios of headspace concentrations in empty vials and those of acidified buffer solutions were less than 1.0. 95% of the H2S was in headspace with the remaining 5% in solution upon acidification. The values for MM were 80% in headspace and 20% in solution. Different buffer solutions also influence the rate of removal of mercaptans from reaction vessels. For methylmercaptan oxidase, using Tris/HCl buffer, the highest level of oxygen uptake was recorded at pH 8.5. Mild changes in the pH levels were recorded at the end of the reactions. Compared to Tris/HCl buffer, phosphate buffer supports a significantly lower reactivity of MMoxidase towards methylmercaptan

Monitoring of microbial hydrocarbon remediation in the soil

Bioremediation of hydrocarbon pollutants is advantageous owing to the cost-effectiveness of the technology and the ubiquity of hydrocarbon-degrading microorganisms in the soil. Soil microbial diversity is affected by hydrocarbon perturbation, thus selective enrichment of hydrocarbon utilizers occurs. Hydrocarbons interact with the soil matrix and soil microorganisms determining the fate of the contaminants relative to their chemical nature and microbial degradative capabilities, respectively. Provided the polluted soil has requisite values for environmental factors that influence microbial activities and there are no inhibitors of microbial metabolism, there is a good chance that there will be a viable and active population of hydrocarbon-utilizing microorganisms in the soil. Microbial methods for monitoring bioremediation of hydrocarbons include chemical, biochemical and microbiological molecular indices that measure rates of microbial activities to show that in the end the target goal of pollutant reduction to a safe and permissible level has been achieved. Enumeration and characterization of hydrocarbon degraders, use of micro titer plate-based most probable number technique, community level physiological profiling, phospholipid fatty acid analysis, 16S rRNA- and other nucleic acid-based molecular fingerprinting techniques, metagenomics, microarray analysis, respirometry and gas chromatography are some of the methods employed in bio-monitoring of hydrocarbon remediation as presented in this review