ABSTRACT
Petroleum hydrocarbon pollutants are difficult to be degraded, and bioremediation has received increasing attention for remediating the hydrocarbon polluted area. This review started by introducing the interphase adaptation and transport process of hydrocarbon by microbes. Subsequently, the advances made in the identification of hydrocarbon-degrading strains and genes as well as elucidation of metabolic pathways and underpinning mechanisms in the biodegradation of typical petroleum hydrocarbon pollutants were summarized. The capability of wild-type hydrocarbon degrading bacteria can be enhanced through genetic engineering and metabolic engineering. With the rapid development of synthetic biology, the bioremediation of hydrocarbon polluted area can be further improved by engineering the metabolic pathways of hydrocarbon-degrading microbes, or through design and construction of synthetic microbial consortia.
Subject(s)
Bacteria/genetics , Biodegradation, Environmental , Hydrocarbons , Petroleum , Petroleum Pollution/analysis , Soil Microbiology , Soil PollutantsABSTRACT
Aim: The aim of this study was to investigate the effect of chronic exposure to petroleum hydrocarbon pollution (PHC) on some biochemical parameters of the fruit juice of Citrus sinensis. Place and Duration of study: This study was carried out at Ebocha-Egbema and Uvuru Mbaise in Imo state (Niger Delta Area), Nigeria between October 2008 and October 2011. Methodology: Acidity (pH), concentrations of ascorbic acid (AA), glutathione (GSH), citric acid, glucose and the activity of lactate dehydrogenase (LDH) in the juice of just-ripe orange fruits (Citrus sinensis) from the two environments were investigated by standard methods. The estimated values were analyzed using student t-test and the results expressed as mean ± standard deviation. Results: The results obtained revealed that there was no significant (p≥0.05) difference in the mean pH values, ascorbic acid and glucose concentrations of the fruit juice from the two areas studied. Mean concentrations of glutathione and citric acid in the juice from Ebocha (0.44±0.09 and 18.80±1.14mg/l) were significantly (p≤0.05) lower than the values in the juice from Uvuru (0.66±0.10 and 21.43±2.02 mg/l), respectively. The results also showed that the mean activity of lactate dehydrogenase was significantly higher in the juice from Ebocha (7.033+/-1.73 U/l) than in that from Uvuru (5.344±1.74 U/l). Conclusion: The findings of this study are suggestive of a possible alteration in the metabolic activities of Citrus sinensis trees evident in its fruit juice due to the PHC pollution in Ebocha in the Niger Delta.
ABSTRACT
Aim: To achieve bioremediation of hydrocarbon impacted mangrove soil using organic (sterile and non-sterile poultry wastes) and inorganic nutrient (NPK). Study Design: Three treatments and the control designs were setup in three replicates and kept in the laboratory at room temperature (28±2°C) throughout the investigation period (6 weeks). Three of the set-ups designated Treatments (SPW, NSPW and NPK) were treated with sterile poultry wastes, non-sterile poultry wastes, nitrogen – phosphorus- potassium, respectively, while the fourth set – up with no treatment were designated control (CTRL). Set ups SPW, NSPW and NPK were designed to determine the effects of sterile poultry wastes, non-sterile poultry wastes and NPK in bioremediation of hydrocarbon polluted soil, respectively. However, the control (CTRL) was designed to determine the contribution made by indigenous (autochthonous) microorganisms and natural attenuation to the soil. Place and Duration of Study: Department of Microbiology, Faculty of Biological Sciences, University of Port Harcourt, Rivers State, Nigeria, between August, 2012 and June, 2013. Methodology: A laboratory-scale study was carried out using organic (sterile and non-sterile poultry wastes) and inorganic nutrient (NPK) to achieve bioremediation of hydrocarbon impacted mangrove soil. Results: In a 42 day study, the sterile poultry wastes (SPW) treated option had an increase in total logarithmic heterotrophic bacterial count from 5.19±0.01 to 7.64±0.08 while non-sterile poultry wastes (NSPW) increased from 5.22±0.11 to 7.65±0.06. The logarithmic heterotrophic bacterial population of the NPK set-up increased from 5.23±0.11 to 7.90±0.10. The untreated set up had its total logarithmic heterotrophic bacterial count increased from 5.14±0.07 to 6.63±0.08. The total logarithmic hydrocarbon utilizing bacteria in SPW, NSPW and NPK treated options increased from 3.70±0.10 to 7.11±0.10, 3.82±0.10 to 7.20±0.10 and 3.93±0.08 to 7.73±0.07, respectively, at which time the corresponding value obtained for untreated increased from 3.63±0.06 to 5.56±0.06. Statistical analyses showed significant difference at p<0.05 level for the four conditions. Several genera of bacteria were isolated as hydrocarbon utilizing bacteria. They include Bacillus sp., Citrobacter sp., Corynebacterium, Escherichia sp., Flavobacterium, Micrococcus, Pseudomonas sp., Salmonella sp. and Vibrio sp. The conductivity values nitrate and phosphate concentrations in SPW, NSPW, and NPK options decreased progressively with slight decrease in the untreated. At day 42, the changes in total petroleum hydrocarbon (TPH) decreased to 498.14±0.01 ppm, 389.42±0.01 ppm, 285.38±0.01 ppm and 1087.00±0.01 ppm in SPW, NSPW, NPK and untreated, respectively. Conclusion: The use of organic sources such as poultry wastes (sterile and non-sterile) and inorganic nutrient (NPK) has shown good promises in the bioremediation of hydrocarbon impacted mangrove soil.
ABSTRACT
The present investigation was carried out to study the response of different concentrations of treated petroleum sludge on seed germination, root and shoot length and tolerance of Vigna unguiculata (L.) Walp. The biologically treated petroleum sludge with bacterial consortium showed 54.8% reduction in total petroleum hydrocarbons. Treated sludge was utilized with agricultural soil in known concentration for the assessment of growth of V. unguiculata. A remarkable absence of seed germination was observed at higher sludge concentration. The different concentrations of treated petroleum sludge showed severe decline on the length, weight and vigour index of the tested seedlings with increasing sludge concentrations. The results showed that the difference in rate of seed germination was significant among various concentrations. Under environmental stress condition, germination is the most critical phase of life cycle in crop plants. In this present study, the high oil content found to alter the osmotic relation between seed and water and thus reduce the amount of water absorbed. It was concluded that the concentration of nutrients and oil present in the treated sludge were toxic to the plant.
ABSTRACT
The effect of chronic exposure to petroleum hydrocarbon (PHC) pollution on the concentrations of glucose, serum and liver malondialdehyde (MDA), protein carbonyl and the histology of liver tissues of the native fowl (Gallus domesticus) from Egbema in the Niger Delta Area (NDA) was studied. Identical fowls from an unpolluted area of Mbaise served as the control. Results showed no significant difference (P<0.05) in the mean glucose concentration obtained for fowls from both environments. The values obtained for serum and liver MDA and protein carbonyl for the test and control fowls were found to be significantly (P<0.05) different. There were elevated concentrations of MDA, protein carbonyl in the serum as well as MDA from liver homogenates of fowls from Egbema when compared to those of fowls from Mbaise. Histological changes were also observed in the liver sections of fowls from Egbema as against none in the liver sections of fowls from Mbaise. These changes were characteristically necrotic and inflammatory. Thus, the findings from this study show, in clear terms, that PHC pollution (crude oil and gas flaring) markedly affected the Egbema environment and induced changes in tissues of the native fowl whose nativity and ancestry are from there.
ABSTRACT
Aims: The aim of the study was to carry-out laboratory–scale bioremediation of petroleum hydrocarbon polluted mangrove swamps using cow dung as source of limiting of nutrients. Methodology and Results: In a 70 days study, the cow dung treated polluted soil had its total culturable hydrocarbon utilising bacterial/fungi, heterotrophic bacterial and fungal counts increased progressively from the 28th day to the 70th day. The control set- up showed very slight increment in its microbial growth. Alkaline pH was observed in all the treatments and control during the study period. The conductivity values of cow dung decreased progressively. In the cow dung treatment option, the nitrate concentration decreased from 35.44 mg/kg to 14.28 mg/kg. Phosphate concentration of cow dung option decreased from 25.41 mg/kg to 9.31mg/kg. The control had the nitrate decreased from 8.42 mg/kg to 6.98 mg/kg. Percentage total organic carbon (% TOC) in the cow dung option decreased from 4.06% to 0.96%. Control experiment had the % TOC decreased from 3.32% to 2.99%. Studies using Gas chromatographic analyses showed that 0%, 49.88%, and 69.85% of Total petroleum hydrocarbon (TPH) were lost at zero hour, 28th day and 70th day respectively in the cow dung option. In addition, in the control experimental set-up, 0%, 7.14% and 13.42% of TPH were lost at zero hour, 28th day and 70th day respectively. Conclusion, significance and impact of study: The use of organic nutrient sources such as cow dung has shown good promises in bioremediation of crude oil impacted Mangrove Swamps in the Niger Delta. The next line of action is to transfer the technology to pilot scale study.
ABSTRACT
Were evaluated natural attenuation, biostimulation and bioaugmentation on the degradation of total petroleum hydrocarbons (TPH) in soils contaminated with diesel oil. Bioaugmentation showed the greatest degradation in the light (C12 - C23) fractions (72.7%) and heavy (C23 - C40) fractions of TPH (75.2%) and natural attenuation was more effective than biostimulation. The greatest dehydrogenase activity was observed upon bioaugmentation of the Long Beach soil (3.3-fold) and the natural attenuation of the Hong Kong soil sample (4.0-fold). The number of diesel oil degrading microorganisms and heterotrophic population was not influenced by the bioremediation treatments. The best approach for bioremediation of soil contaminated with diesel oil is the inoculum of microorganisms pre-selected from their own environment.
Avaliou-se a degradação de hidrocarbonetos de petróleo (HP) em solos contaminados com óleo diesel através da atenuação natural, bioestimulação e bioaumentação. A bioaumentação apresentou a maior degradação da fração leve (72,6%) e da fração pesada (75,2%) de HP e a atenuação natural foi mais efetiva do que a bioestimulação. A maior atividade da dehidrogenase no solo Long Beach e Hong Kong foi observada nos tratamentos bioaumentação e atenuação natural, respectivamente. O número de microrganismos degradadores de diesel e a população de heterotróficos não foi influenciada pelas técnicas de biorremediação. A melhor performance para a biorremediação do solo contaminado com diesel foi obtida quando foram adicionados microrganismos pré-selecionados do ambiente contaminado.
ABSTRACT
Were evaluated natural attenuation, biostimulation and bioaugmentation on the degradation of total petroleum hydrocarbons (TPH) in soils contaminated with diesel oil. Bioaugmentation showed the greatest degradation in the light (C12 - C23) fractions (72.7%) and heavy (C23 - C40) fractions of TPH (75.2%) and natural attenuation was more effective than biostimulation. The greatest dehydrogenase activity was observed upon bioaugmentation of the Long Beach soil (3.3-fold) and the natural attenuation of the Hong Kong soil sample (4.0-fold). The number of diesel oil degrading microorganisms and heterotrophic population was not influenced by the bioremediation treatments. The best approach for bioremediation of soil contaminated with diesel oil is the inoculum of microorganisms pre-selected from their own environment.
Avaliou-se a degradação de hidrocarbonetos de petróleo (HP) em solos contaminados com óleo diesel através da atenuação natural, bioestimulação e bioaumentação. A bioaumentação apresentou a maior degradação da fração leve (72,6%) e da fração pesada (75,2%) de HP e a atenuação natural foi mais efetiva do que a bioestimulação. A maior atividade da dehidrogenase no solo Long Beach e Hong Kong foi observada nos tratamentos bioaumentação e atenuação natural, respectivamente. O número de microrganismos degradadores de diesel e a população de heterotróficos não foi influenciada pelas técnicas de biorremediação. A melhor performance para a biorremediação do solo contaminado com diesel foi obtida quando foram adicionados microrganismos pré-selecionados do ambiente contaminado.