Activity of a crude biosurfactant extracted from the culture fluid of Serratia sp. that was isolated from riverbed soil was shown to increase in proportion to the cultivation time, and was higher at pH 8 than at pH 7....Activity of a crude biosurfactant extracted from the culture fluid of Serratia sp. that was isolated from riverbed soil was shown to increase in proportion to the cultivation time, and was higher at pH 8 than at pH 7. Serratia sp. grew in the mineral-based medium with soybean oil but was not with kerosene-diesel. The petroleum-degrading bacteria—Acinetobacter sp., Pseudomonas sp., Paracoccus sp., and Cupriavidus sp.—were isolated from a specially designed enrichment culture. The efficiency of mineralization of wastewater contaminated with kerosene and diesel (WKD) by the petroleum-degrading bacterial community (PDBC) was enhanced significantly by addition of the crude biosurfactant. The efficiency of mineralization of the WKD was also about 2 times boosted by co-culture of Serratia sp. and PDBC. Bacterial community of Serratia sp. and PDBC co-cultivated in the WKD was maintained for at least 8 days according to the TGGE pattern of 16S rDNA obtained from the bacterial culture. In conclusion, the co-culture of Serratia sp. and PDBC is an applicable technique for the mineralization of wastewater contaminated with petroleum, which may substitute for chemical or biological surfactant.展开更多
Surface water sources in the oil producing Niger Delta region of Nigeria are highly susceptible to pollution by petroleum hydrocarbons and so it is important to understand the microbial diversity of such ecosystems. W...Surface water sources in the oil producing Niger Delta region of Nigeria are highly susceptible to pollution by petroleum hydrocarbons and so it is important to understand the microbial diversity of such ecosystems. Water and sediment samples were collected between April-August, 2013 from Bodo creeks and taken to Environmental Microbiology laboratory of University of Portharcourt for analysis. A total of thirty aerobic heterotrophic bacterial strains isolated ranged from 3.0 - 7.0 × 104 cfu for surface water and 1.6 - 5.6 × 104 cfu for sediment samples of Bodo creek using serial dilution and spread plate technique. Pure cultures of bacteria were obtained on the basis of their morphological characteristics and subjected to biochemical tests and further classified on the basis of 16S rRNA gene sequence analysis. The DNA was isolated from size fractionated samples and the diversity of bacteria in each fraction was studied using PCR amplification of partial 16S rRNA. The sequences were submitted to NCBIGen bank for identification and assigning of accession numbers. The isolated aerobic heterotrophic bacteria belong to the families of Enterobacteriaceae, Bacilliceae, Alcaligenaceae, Pseudomonadaceae, Flavobactericeae and Planococcaceae.展开更多
Geo-microbial prospecting for hydrocarbons is an exploration method based on the seepage of light gaseous hydrocarbons from oil/gas reservoirs to the surface and their utilization by hydrocarbon oxidizing bacteria. Th...Geo-microbial prospecting for hydrocarbons is an exploration method based on the seepage of light gaseous hydrocarbons from oil/gas reservoirs to the surface and their utilization by hydrocarbon oxidizing bacteria. These bacteria utilize hydrocarbon gases as their sole source of food and are found to be enriched in the near surface soils/sediments above the oil and gas reservoirs. The detection of anomalous populations of n-pentane and n-hexane oxidizing bacteria in the surface soils can help to evaluate the prospects for hydrocarbon exploration. A geo-microbial survey has been carried out in the Bikaner Nagaur basin to investigate the prospects for hydrocarbon exploration. In the present study, bacterial counts for n-pentane utilizing bacteria range between 2.0× 10^2 and 1.26× 10^6 cfu/gm and n-hexane utilizing bacteria range between 2.0× 10^2 and 1.21 × 10^6 cfu/gm. The bacterial concentration distribution maps show four distinct anomalies in the study area. The possibility of discovering oil or gas reservoirs using the microbiological method is emphasized by the tact that the hydrocarbon-oxidizing bacteria range between 103 and 106 cfu/gm in soil/sediment receiving hydrocarbon micro-seepages. In the present study area of the Bikaner Nagaur basin, n-pentane and n-hexane utilizing bacteria are found between 105 and 106 cfu/gm of soil sample, which is significant and thereby substantiates the seepage of lighter hydrocarbon accumulations from oil and gas reservoirs. Geo-microbial prospecting studies suggest that hydrocarbon micro-seepage of subsurface origin is present in the study area and indicate that the area has positive prospects for petroleum exploration.展开更多
This study was designed and carried out to characterize hydrocarbonoclastic microbial communities in soil polluted with artisanal refined hydrocarbon at Trans Amadi, Phalga Local Government Area of Rivers State, Niger...This study was designed and carried out to characterize hydrocarbonoclastic microbial communities in soil polluted with artisanal refined hydrocarbon at Trans Amadi, Phalga Local Government Area of Rivers State, Nigeria. Heterotrophic bacteria count ranged from 8.0 × 10<sup>5</sup> cfu/gm for sample TSAS1, and 2.1 × 10<sup>6</sup> cfu/gm for sample TSAS2 while TSAS3 was too numerous to count (TNTC). Hydrocarbon utilizing bacteria count ranged from 1.1 × 10<sup>5</sup> cfu/gm for TSAS1, and 5.9 × 10<sup>4</sup> cfu/gm for TSAS2, while TSAS3 was 5.4 × 10<sup>4</sup> cfu/gm. Physiochemical parameters of the soil were determined. The ranges obtained were pH 6.6, conductivity 125 μs/cm, temperature 27.3°C, moisture 7.72, total nitrogen 0.056%, phosphate 1.554 ppm, potassium 145.87 ppm, lead 7.02 ppm, cadmium 0.41 ppm, nickel 1.96 ppm, copper 1.14 ppm, total petroleum hydrocarbon 1487.24181 ppm, polycyclic aromatic hydrocarbon 12.85287 ppm. Isolates of hydrocarbon utilizing bacteria characterized belonged to the genera Escherichia coli, Klebsiella sp., Lactobacillus sp., Enterobacter sp., Serratia sp., and Proteus sp. The findings in this study have revealed the abilities of these groups of bacteria to be employed in bioremediation/biodegradation clean-up practices. Thus the polluted soil may harbour important genera of bacterial species that may have beneficial applications in environmental microbiology for future remediation processes.展开更多
In the Niger Delta region of Nigeria, oil explorations and exploitations abound, causing environmental pollution with serious consequences on soil ecosystem and its biodiversity. In spite of the relationship between m...In the Niger Delta region of Nigeria, oil explorations and exploitations abound, causing environmental pollution with serious consequences on soil ecosystem and its biodiversity. In spite of the relationship between microbes and fauna in soil ecosystem, such that both organisms can metabolize certain range of petroleum hydrocarbon substrates with the fauna influencing the remediation potentials of bacteria, yet soil fauna is still not fully considered in bioremediation. The influence of earthworm;Lumbricus terrestris on the remediating potentials of soil bacteria in petroleum hydrocarbon contaminated soils was investigated. Eighteen pots were filled with 700 g of soil each, with nine treated with mixture of 3 levels crude oil and remediated with earthworm, while the other nine had no earthworm. The total petroleum hydrocarbon (TPH), soil physical, nutrient compositions, and TPH degrading bacteria biodiversity were determined before contamination or commencement of study and thirty days after. The results showed a decrease in TPH concentration of 55.58%, 62.57% and 67.07% in 1 ml, 2 ml and 3 ml crude oil contaminated soil, respectively. Species richness and abundance of bacteria organisms increased with high relative abundance in soils remediated with earthworms, hydrocarbon utilizing bacteria increased from less than 0.1 cfu/g to 0.4 cfu/g, and total heterotrophic bacteria 1.6 cfu/g at the end of the study. Earthworms increased rate of remediation potentials of bacteria, such that within 30 days post remediation treatment, 34.14% of reduced concentration was achieved over soil samples without earthworms at 3 ml, and 25.14% at 2 ml concentration. Reduction in pH levels in remediated soils was between 6.39 to 6.17 and 6.74 to 6.72 in unremediated soils, while moisture content was 6.73% to 6.77% unremediated and 5.85% to 6.62% in earthworm remediated soils. Total organic carbon, nitrates in soils inoculated with earthworms were lower in concentration than those without earthworms. Reverse was the case with potassium, phosphate and phosphorous concentrations which were above those without earthworms. Results indicate statistically, significant difference between reduction in TPH in earthworm remediated soils and unremediated soils, pointing out that earthworm is a good candidate for facilitation of bacteria remediation-petroleum hydrocarbon contamination.展开更多
文摘Activity of a crude biosurfactant extracted from the culture fluid of Serratia sp. that was isolated from riverbed soil was shown to increase in proportion to the cultivation time, and was higher at pH 8 than at pH 7. Serratia sp. grew in the mineral-based medium with soybean oil but was not with kerosene-diesel. The petroleum-degrading bacteria—Acinetobacter sp., Pseudomonas sp., Paracoccus sp., and Cupriavidus sp.—were isolated from a specially designed enrichment culture. The efficiency of mineralization of wastewater contaminated with kerosene and diesel (WKD) by the petroleum-degrading bacterial community (PDBC) was enhanced significantly by addition of the crude biosurfactant. The efficiency of mineralization of the WKD was also about 2 times boosted by co-culture of Serratia sp. and PDBC. Bacterial community of Serratia sp. and PDBC co-cultivated in the WKD was maintained for at least 8 days according to the TGGE pattern of 16S rDNA obtained from the bacterial culture. In conclusion, the co-culture of Serratia sp. and PDBC is an applicable technique for the mineralization of wastewater contaminated with petroleum, which may substitute for chemical or biological surfactant.
文摘Surface water sources in the oil producing Niger Delta region of Nigeria are highly susceptible to pollution by petroleum hydrocarbons and so it is important to understand the microbial diversity of such ecosystems. Water and sediment samples were collected between April-August, 2013 from Bodo creeks and taken to Environmental Microbiology laboratory of University of Portharcourt for analysis. A total of thirty aerobic heterotrophic bacterial strains isolated ranged from 3.0 - 7.0 × 104 cfu for surface water and 1.6 - 5.6 × 104 cfu for sediment samples of Bodo creek using serial dilution and spread plate technique. Pure cultures of bacteria were obtained on the basis of their morphological characteristics and subjected to biochemical tests and further classified on the basis of 16S rRNA gene sequence analysis. The DNA was isolated from size fractionated samples and the diversity of bacteria in each fraction was studied using PCR amplification of partial 16S rRNA. The sequences were submitted to NCBIGen bank for identification and assigning of accession numbers. The isolated aerobic heterotrophic bacteria belong to the families of Enterobacteriaceae, Bacilliceae, Alcaligenaceae, Pseudomonadaceae, Flavobactericeae and Planococcaceae.
文摘Geo-microbial prospecting for hydrocarbons is an exploration method based on the seepage of light gaseous hydrocarbons from oil/gas reservoirs to the surface and their utilization by hydrocarbon oxidizing bacteria. These bacteria utilize hydrocarbon gases as their sole source of food and are found to be enriched in the near surface soils/sediments above the oil and gas reservoirs. The detection of anomalous populations of n-pentane and n-hexane oxidizing bacteria in the surface soils can help to evaluate the prospects for hydrocarbon exploration. A geo-microbial survey has been carried out in the Bikaner Nagaur basin to investigate the prospects for hydrocarbon exploration. In the present study, bacterial counts for n-pentane utilizing bacteria range between 2.0× 10^2 and 1.26× 10^6 cfu/gm and n-hexane utilizing bacteria range between 2.0× 10^2 and 1.21 × 10^6 cfu/gm. The bacterial concentration distribution maps show four distinct anomalies in the study area. The possibility of discovering oil or gas reservoirs using the microbiological method is emphasized by the tact that the hydrocarbon-oxidizing bacteria range between 103 and 106 cfu/gm in soil/sediment receiving hydrocarbon micro-seepages. In the present study area of the Bikaner Nagaur basin, n-pentane and n-hexane utilizing bacteria are found between 105 and 106 cfu/gm of soil sample, which is significant and thereby substantiates the seepage of lighter hydrocarbon accumulations from oil and gas reservoirs. Geo-microbial prospecting studies suggest that hydrocarbon micro-seepage of subsurface origin is present in the study area and indicate that the area has positive prospects for petroleum exploration.
文摘This study was designed and carried out to characterize hydrocarbonoclastic microbial communities in soil polluted with artisanal refined hydrocarbon at Trans Amadi, Phalga Local Government Area of Rivers State, Nigeria. Heterotrophic bacteria count ranged from 8.0 × 10<sup>5</sup> cfu/gm for sample TSAS1, and 2.1 × 10<sup>6</sup> cfu/gm for sample TSAS2 while TSAS3 was too numerous to count (TNTC). Hydrocarbon utilizing bacteria count ranged from 1.1 × 10<sup>5</sup> cfu/gm for TSAS1, and 5.9 × 10<sup>4</sup> cfu/gm for TSAS2, while TSAS3 was 5.4 × 10<sup>4</sup> cfu/gm. Physiochemical parameters of the soil were determined. The ranges obtained were pH 6.6, conductivity 125 μs/cm, temperature 27.3°C, moisture 7.72, total nitrogen 0.056%, phosphate 1.554 ppm, potassium 145.87 ppm, lead 7.02 ppm, cadmium 0.41 ppm, nickel 1.96 ppm, copper 1.14 ppm, total petroleum hydrocarbon 1487.24181 ppm, polycyclic aromatic hydrocarbon 12.85287 ppm. Isolates of hydrocarbon utilizing bacteria characterized belonged to the genera Escherichia coli, Klebsiella sp., Lactobacillus sp., Enterobacter sp., Serratia sp., and Proteus sp. The findings in this study have revealed the abilities of these groups of bacteria to be employed in bioremediation/biodegradation clean-up practices. Thus the polluted soil may harbour important genera of bacterial species that may have beneficial applications in environmental microbiology for future remediation processes.
文摘In the Niger Delta region of Nigeria, oil explorations and exploitations abound, causing environmental pollution with serious consequences on soil ecosystem and its biodiversity. In spite of the relationship between microbes and fauna in soil ecosystem, such that both organisms can metabolize certain range of petroleum hydrocarbon substrates with the fauna influencing the remediation potentials of bacteria, yet soil fauna is still not fully considered in bioremediation. The influence of earthworm;Lumbricus terrestris on the remediating potentials of soil bacteria in petroleum hydrocarbon contaminated soils was investigated. Eighteen pots were filled with 700 g of soil each, with nine treated with mixture of 3 levels crude oil and remediated with earthworm, while the other nine had no earthworm. The total petroleum hydrocarbon (TPH), soil physical, nutrient compositions, and TPH degrading bacteria biodiversity were determined before contamination or commencement of study and thirty days after. The results showed a decrease in TPH concentration of 55.58%, 62.57% and 67.07% in 1 ml, 2 ml and 3 ml crude oil contaminated soil, respectively. Species richness and abundance of bacteria organisms increased with high relative abundance in soils remediated with earthworms, hydrocarbon utilizing bacteria increased from less than 0.1 cfu/g to 0.4 cfu/g, and total heterotrophic bacteria 1.6 cfu/g at the end of the study. Earthworms increased rate of remediation potentials of bacteria, such that within 30 days post remediation treatment, 34.14% of reduced concentration was achieved over soil samples without earthworms at 3 ml, and 25.14% at 2 ml concentration. Reduction in pH levels in remediated soils was between 6.39 to 6.17 and 6.74 to 6.72 in unremediated soils, while moisture content was 6.73% to 6.77% unremediated and 5.85% to 6.62% in earthworm remediated soils. Total organic carbon, nitrates in soils inoculated with earthworms were lower in concentration than those without earthworms. Reverse was the case with potassium, phosphate and phosphorous concentrations which were above those without earthworms. Results indicate statistically, significant difference between reduction in TPH in earthworm remediated soils and unremediated soils, pointing out that earthworm is a good candidate for facilitation of bacteria remediation-petroleum hydrocarbon contamination.
