Total Petroleum Hydrocarbon Degradation Research Articles

The effect of different in situ chemical oxidation (ISCO) technologies on the survival of indigenous microbes and the remediation of petroleum hydrocarbon-contaminated soil

This study determines the effect of different in situ chemical oxidation (ISCO) technologies on soil microorganisms and total petroleum hydrocarbon (TPH) degradation. Permanganate is a moderate oxidant to the intrinsic microbes while persulfate causes severe bacterial death. TPH removal in the persulfate and permanganate systems is similar, which is higher than that in the hydrogen peroxide system. Permanganate is the most suitable oxidant for ISCO, followed by in situ bioremediation because of its persistence and low toxicity. Chemical oxidation dominates the removal of TPH throughout the experiment in the persulfate systems and during the initial stage in the hydrogen peroxide and permanganate systems. The toxicity of different catalysis/activation methods to in situ microbes decreases in the order: heat> Fe2+/citric acid> Fe2+>no catalysis/activation. If ferrous iron or citric acid is used to catalyze hydrogen peroxide, the pH must be controlled to prevent severe damage to the microbes. There is more dissolved organic carbon in solution in oxidation systems, which shows that the addition of an oxidant increases the solubility and bioavailability of the contaminant. Petroleum degraders are present in the contaminated soil and the addition of oxidants changes indigenous bacterial communities significantly.

Assessment of Total Petroleum Hydrocarbon Degradation by Endophytic Fungi Isolated from Water Hyacinth (Eichhornia Crassipes)

Petroleum exploitation has negative impacts on the environment, such as oil spills, likewise, health implications on humans. The ability of newly isolated six fungal endophytes for degrading total petroleum hydrocarbons was evaluated. Their ability for hydrocarbon biodegradation was assessed in vitro for 35 days, using the minimal salt medium incorporated with products of crude oil, like petrol, kerosene, diesel, spent engine oil, unspent engine oil as the carbon source. Each fungus was introduced into test tubes containing minimal salt medium and petroleum products, the tubes were then incubated on shaker incubator at 27ºC, 151rpm for 35days. At every 7days, turbidity was measured with photoelectric colorimeter at wavelength of 530nm. In this study, the petroleum hydrocarbon degrading fungi isolated from Water Hyacinth leaves were identified using morphological techniques. The six fungi isolated were identified as; Aspergillus niger, Penicillium canescens, Penicillium atrovenetum, Trichocladium opacum, Thermomyces lanuginosus and Penicillium spp. In this experiment, it was evident that all the fungi were able to utilize hydrocarbons for their growth, at different rates. Aspergillus niger demonstrated high capacity to biodegrade diesel and spent engine oil, Penicillium canescens was excellent to utilize petrol, while Penicillium atrovenetum had the potential to degrade unspent engine oil and kerosene. The results obtained suggest that these endophytic fungal isolates are potential hydrocarbon biodegraders that could be used in bioremediation processes.

Potential of indigenous biosurfactant-producing fungi from real crude oil sludge in total petroleum hydrocarbon degradation and its future research prospects

In this study, biosurfactant-producing fungi isolated from crude oil sludge were tested to degrade total petroleum hydrocarbons (TPHs) in contaminated sludge. Polymerase chain reaction (PCR) was performed, and the phylogenetic tree based on the fungi genomic sequence was constructed using MEGA-X software and had identified the isolated fungi as Aspergillus terrus isolate Shu1 and Aspergillus fumigatus isolate Shu2 species. A. fumigatus isolate Shu2 showed a better potential of biosurfactant-producing fungi compared to A. terrus isolate Shu1, based on qualitative (parafilm, drop collapse, oil spreading, emulsion index) and quantitative (surface tension) analyses. Further TPH degradation by A. fumigatus isolate Shu2 was done under two conditions with the absence of additional nutrition and with additional nutrition for 45 days. Gas chromatography-flame ionisation detector (GC-FID) analysis showed TPH degradation by A. fumigatus of approximately 57 ± 2% in the first 16 days of treatment. The addition of nutrients inside the system had significantly increased (p < 0.05) the total removal of TPH up to 63 ± 2% (6% higher) within the 16 days. These findings suggest that A. fumigatus isolate Shu2 is a good potential as biosurfactant-producing fungi and is capable of degrading TPH from contaminated sludge. This study also verified that the TPH content of hydrocarbon-contaminated sludge was significantly reduced in the treatment with the presence of additional nutrient.

Comparative Analysis of Microbial Consortiums and Nanoparticles for Rehabilitating Petroleum Waste Contaminated Soils.

Nano-bioremediation application is an ecologically and environmentally friendly technique to overcome the catastrophic situation in soil because of petroleum waste contamination. We evaluated the efficiency of oil-degrading bacterial consortium and silver nanoparticles (AgNPs) with or without fertilizer to remediate soils collected from petroleum waste contaminated oil fields. Physicochemical characteristics of control soil and petroleum contaminated soils were assessed. Four oil-degrading strains, namely Bacillus pumilus (KY010576), Exiguobacteriaum aurantiacum (KY010578), Lysinibacillus fusiformis (KY010586), and Pseudomonas putida (KX580766), were selected based on their in vitrohydrocarbon-degrading efficiency. In a lab experiment, contaminated soils were treated alone and with combined amendments of the bacterial consortium, AgNPs, and fertilizers (ammonium nitrate and diammonium phosphate). We detected the degradation rate of total petroleum hydrocarbons (TPHs) of the soil samples with GC-FID at different intervals of the incubation period (0, 5, 20, 60, 240 days). The bacterial population (CFU/g) was also monitored during the entire period of incubation. The results showed that 70% more TPH was degraded with a consortium with their sole application in 20 days of incubation. There was a positive correlation between TPH degradation and the 100-fold increase in bacterial population in contaminated soils. This study revealed that bacterial consortiums alone showed the maximum increase in the degradation of TPHs at 20 days. The application of nanoparticles and fertilizer has non-significant effects on the consortium degradation potential. Moreover, fertilizer alone or in combination with AgNPs and consortium slows the rate of degradation of TPHs over a short period. Still, it subsequently accelerates the rate of degradation of TPHs, and a negligible amount remains at the end of the incubation period.

Strategic implementation of integrated bioaugmentation and biostimulation for efficient mitigation of petroleum hydrocarbon pollutants from terrestrial and aquatic environment

Release of petroleum hydrocarbon pollutants poses a serious problem to the terrestrial as well as marine ecosystem. This study investigated and compared the potency of different biodegradation strategies for mitigating total petroleum hydrocarbon (TPH) of petroleum refinery sludge by an integrated action of bioaugmentation and biostimulation vis-à-vis separate bioaugmentation and biostimulation approaches. The implementation of a concomitant bioaugmentation-biostimulation strategy (BABSS) involving the indigenously developed bacterial consortium and poultry litter extract showed the best performance by mitigating the TPH up to 90.3 ± 3.7% in 21 days. The GC-FID analysis confirmed the efficacy of different TPH degradation strategies. The kinetic study of TPH degradation of BABSS resulted first-order with rate 0.11 day−1. Thus, the BABSS proved to be more efficient in degrading TPH in an eco-friendly manner and hence, may pave the way for better management of petroleum hydrocarbon pollutants, while providing a sustainable solution to the disposal of poultry wastes.

Bioremediation of oil-contaminated soil: Exploring the potential of endogenous hydrocarbon degrader Enterobacter sp. SAVR S-1

Enterobacter is commonly found in oil-contaminated soil and plays a vital role in environmental bioremediation. This paper selected Enterobacter sp. SAVR S-1 as a representative to study the degradation potential at different concentrations of Total petroleum hydrocarbon (TPH) in soil during bioremediation. Genomic analysis indicated that genes involved in the metabolism of aromatic compounds (paa and hpa gene clusters) and fatty acid metabolism genes (fad gene cluster) might play important roles in TPH bioremediation. Through an increase (of up to 53.13%) in the abundance of microbial communities in oil-contaminated soils, TPH decreased, and Enterobacter was the dominant genus. The relative abundance of potential endogenous hydrocarbon degraders, i.e., halobacteria, greatly increased, including Aliifodinibius (1.26–1.59%), Filobacillus (0.02–0.66%), Pontibacillus (0.02–0.68%) and Halomonas (0.27–3.28%). Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) analysis showed enhanced gene allocation for ABC transporters (4.22%), fatty acid (0.14%), benzoate (0.65%), butanoate (1.29%), propanoate (1.35%) metabolism and aromatic compound (0.28%) degradation on day 30. This study indicated that the addition of bacterial sources can induce community dynamics and their metabolic interactions in oil-contaminated soils to further accelerate bioremediation effects and provided a mechanistic basis for TPH degradation using the endogenous hydrocarbon degrader Enterobacter.

Synergetic effects of microbial-phytoremediation reshape microbial communities and improve degradation of petroleum contaminants

Microbial-phytoremediation is an effective bioremediation technology that introduces petroleum-degrading bacteria and oil-tolerant plants into oil-contaminated soils in order to achieve effective degradation of total petroleum hydrocarbons (TPH). In this work, natural attenuation (NA), microbial remediation (MR, using Acinetobacter sp. Tust-DM21), phytoremediation (PR, using Suaeda glauca), and microbial-phytoremediation (MPR, using both species) were utilized to degrade petroleum hydrocarbons. We evaluated four different biological treatments, assessing TPH degradation rates, soil enzyme activities, and the structure of microbial community in the petroleum-contaminated soil. This finding revealed that the roots of Suaeda glauca adsorbed small amounts of polycyclic aromatic hydrocarbons, causing the structure of soil microbiota community to reshape. The abundance of petroleum-degrading bacteria and plant growth-promoting rhizobacteria (PGPR) has increased, as has microbial diversity. According to correlation research, these genera increased soil enzyme activity, boosted the number of degradation-functional genes in the petroleum hydrocarbon degradation pathway, and accelerated the dissipation and degradation of TPH in petroleum-contaminated soil. This evidence contributes to a better understanding of the mechanisms involved in the combined microbial-phytoremediation strategies for contaminated soil, specifically the interaction between microflora and plants in co-remediation and the effects on the structural reshaping of rhizosphere microbial communities.

Enhanced degradation of petroleum hydrocarbons in soil by FeS@BC activated persulfate and its mechanism

• FeS@BC/PS system showed enhancement removal of petroleum hydrocarbons in soil. • Biochar prevented FeS aggregation and enhanced stability and removal efficiency. • Higher degradation rate was found for n-alkane compared to PAHs. • SO 4 Â · - is mainly responsible for petroleum hydrocarbons degradation. Rapid degradation of petroleum hydrocarbons by chemical oxidation is currently facing lots of environmental concerns, and green activation methods are highly needed. This study investigated the degradation of total petroleum hydrocarbons (TPHs), polycyclic aromatic hydrocarbons (PAHs), and n-alkanes in soil by FeS@BC and FeS activated persulfate (PS). Various controlling factors including FeS to biochar (BC) mass ratio, PS dosage, FeS@BC dosage, and initial pH were examined. The optimal parameters were obtained by single-factor experiments. Under the optimal condition, the removal rates of TPHs, PAHs, and n-alkanes by a FeS@BC/PS system were 61.83 %, 78.17 %, and 91.56 %, respectively, which were much higher than those of a FeS/PS system (47.91 %, 51.20 %, and 79.31 %, respectively). Radical quenching experiment and Electron Paramagnetic Resonance (EPR) revealed that the dominant active substance is sulfate free radical ( S O 4 · - ) produced by PS during activation. Based on the characterization and data analysis, a possible activation mechanism is proposed: the reduction of Fe 2+ /Fe 3+ and the activation of BC as an electron transfer mediator promote the generation of S O 4 · - . This study demonstrates that the FeS@BC/PS system has a promoting effect on the degradation of petroleum hydrocarbons in soil, which has great potential for remediation of petroleum-contaminated soil.

Efficient removal of heavily oil-contaminated soil using a combination of fenton pre-oxidation with biostimulated iron and bioremediation

Crude oil contamination severely deteriorates soils quality. Bioremediation utilizing soil indigenous organisms could be employed to decompose petroleum hydrocarbons thanks to its low cost and minor environmental disturbance. However, slow kinetics limit the successful application of this biotechnique. Pretreating oil-contaminated soils with Fenton pre-oxidation could accelerate the subsequent bioremediation process. This study was to explore the mechanisms behind the rapid propagation of indigenous petroleum-degrading bacteria (IPDB) and the efficient degradation of total petroleum hydrocarbons (TPH) in soil after Fenton pre-oxidation with biostimulated iron. Biostimulated iron and non-biostimulated iron were used in the experiments, where Fenton pre-oxidation was combined with the bioremediation of oil-contaminated soil (TPH = 13221 mg/kg). Although the amount of Fenton pre-oxidized TPH (3331–3775 mg/kg) was similar with biostimulated and non-biostimulated irons, the biodegradation of TPH after Fenton pre-oxidation with biostimulated iron (5840 mg/kg) was much higher than that with non-biostimulated iron (3034–4034 mg/kg). Moreover, abundant nutrients and a high population of residual IPDB were found after Fenton pre-oxidation with biostimulated iron, which benefited stable consumption of NH3–N and dissolved organic carbon (DOC) by IPDB during the subsequent bioremediation. However, Fenton pre-oxidation with non-biostimulated iron either resulted in greater damage to IPDB or produced fewer nutrients, thereby failing to ensure the continuous propagation of IPDB during the subsequent bioremediation. Therefore, we propose that Fenton pre-oxidation with biostimulated iron should be applied to heavily oil-contaminated soils prior to bioremediation.

Phytoremediation of soils contaminated with crude and weathered oil using two rice varieties (Oryza sativa L.)

Objective: To evaluate the potential for soil phytoremediation with new and weathered hydrocarbons with two rice varieties (Oryza sativa L.). Materials and Methods: The assessed treatments were 150 mg kg-1 (control soil), 30,000; 60,000 and 90,000 mg kg-1 of new oil and 79,457 mg kg-1 of weathered oil 1 and 42,000 of mg kg-1 of weathered oil 2; they were established in a completely randomized design with 6 x 3 factorial, with four repetitions each. The evaluated variables were populations of total bacteria (colony forming units CFU per grams of dry soil), free-living nitrogen-fixing bacteria (CFU), total fungi (CFU), and total dry biomass (g). Total bacteria and fungi were quantified at the beginning of the experiment at 90 and 145 days. Results: The highest total petroleum hydrocarbons (HTP) degradation was 73 and 72 % in the 79,457 and 42,000 mg kg-1 concentrations of weathered HTP 1 and 2, in the rhizosphere of rice silver line 21. The total dry biomass reported significant differences (p ≤ 0.05), evidencing a lower effect in the 60,000 mg kg-1 concentration in new oil, which caused a 33 % reduction compared to the control. Results/Conclusions: The rice variety line 21 has a greater potential to phytoremediate soils contaminated with crude and weathered oil in field conditions in tropical areas.

Free and Immobilized Microbial Culture–Mediated Crude Oil Degradation and Microbial Diversity Changes Through Taxonomic and Functional Markers in a Sandy Loam Soil

Crude oil contamination of soil and water resources is a widespread issue. The present study evaluated the degradation of aliphatic hydrocarbons (C11–C36) in crude oil by 17 bacteria isolated from a crude oil–contaminated soil. The results suggested that Pseudomonas sp. and Bacillus amyloliquefaciens were the best hydrocarbon-degrading bacteria in the presence of surfactant Tween-80 (0.1% w/v). Based on the present investigation and a previous study, Pseudomonas sp. + B. amyloliquefaciens and fungus Aspergillus sydowii were identified as best oil degraders and were immobilized in alginate–bentonite beads, guargum–nanobenonite water dispersible granules (WDGs), and carboxy methyl cellulose (CMC)–bentonite composite. Sandy loam soil was fortified with 1, 2, and 5% crude oil, and total petroleum hydrocarbon (TPH) degradation efficiency of free cultures and bio-formulations was evaluated in sandy loam soils. Compared to a half-life (t1/2) of 69.7 days in the control soil (1% oil), free cultures of Pseudomonas sp. + B. amyloliquefaciens and A. sydowii degraded TPH with t1/2 of 10.8 and 19.4 days, respectively. Increasing the oil content slowed down degradation, and the t1/2 in the control and soils inoculated with Pseudomonas sp. + B. amyloliquefaciens and A. sydowii was 72.9, 14.7, and 22.2 days (2%) and 87.0, 23.4, and 30.8 days (5%), respectively. Supplementing soil with ammonium sulfate (1%) enhanced TPH degradation by Pseudomonas sp. + B. amyloliquefaciens (t1/2–10 days) and A. sydowii (t1/2–12.7 days). All three bio-formulations were effective in degrading TPH (1%), and the t1/2 was 10.7–11.9 days (Pseudomonas sp. + B. amyloliquefaciens and 14–20.2 days (A. sydowii) and were at par with free cultures. Microbial diversity analysis based on taxonomic markers and functional markers suggested that the bioaugmentation process helped keep soil in the active stage and restored the original microbial population to some extent. The present study concluded that bio-formulations of crude oil–degrading microbes can be exploited for its degradation in the contaminated environment.

Reduction of the soil environmental impact caused by the presence of total petroleum hydrocarbons (TPH) by using Pseudomonas sp.

This research focuses on the bioaugmentation with Pseudomonas sp. (native) and Pseudomonas aeruginosa (commercial) for the biodegradation of total petroleum hydrocarbons (TPH) of the environmental soil samples of the AqLab laboratory in Orellana, Ecuador. Two treatments of sterilized soil (one inoculated with the native strain and the other inoculated with the commercial strain), where used for physical- -chemical analyzes as well as the degradation of TPH. They were evaluated every 20 days for a total period of 80–100 days. The native bacterium was isolated from the laboratory agglomerates in a selective culture medium specific for Pseudomonas sp. The biodegradation of the TPH exhibited a positive result after 80 and 100 days of treatment, with a reduction of 84 and 96% of initial TPH after the bacterial inoculation. The comparison between the two strains evaluated, commercial and native, showed a greater efficiency of biodegradation by the native strain isolated directly from the agglomerates, suggesting working with native strains of the place that have a greater adaptability to the contaminated environment that would ensure bioremediation processes faster and more efficient, low cost and environmentally friendly.

Biostimulatory Influence of Biochar on Degradation of Petroleum Hydrocarbon Impacted Soil

Soil pollution caused by petroleum hydrocarbon and its derivatives has become a grave global issue. Physico-chemical techniques are often expensive. However, bioremediation of petroleum hydrocarbon polluted soil is cost-effective. Therefore, the study was carried out to assess the biostimulatory influence of biochar on the degradation of petroleum hydrocarbon impacted soil in NNPC Depot, kano state. Soil samples were randomly collected from the polluted site to obtain a composite sample. About 400 g of the polluted soil was filled into pots and arranged in a 2x2 factorial experiment in a completely randomized design with three replications. Bone and wood char was at 2 levels (0 and 50 g/pot) each. Data were collected on the physicochemical properties (pH, TN, and Av. P) of the soil, Total Petroleum Hydrocarbon (TPH), and bacterial population. Data were analyzed using ANOVA at α0. 05. Results obtained from the study show that biochar application significantly (p&lt;0.05) enhanced TPH degradation and bacterial population in the polluted soil. However, Bone char significantly(p&lt;0.05) enhanced TPH degradation and bacterial population the most compared to wood char. Combined bone and wood char application resulted in significantly (p&lt;0.05) lower residual TPH content in the polluted soil compared to using bone or wood char alone. Thus, bone and wood char should be used in the bioremediation of petroleum hydrocarbon impacted soils.

Optimization of Enzymatic Bioremediation of Oil Contaminated Soil by Laccase from Marasmiellus palmovorus using Response Surface Methodology

Crude oil contamination is considered highly toxic and poses a significant environmental problem. As an alternative, the laccase enzyme showed high performance for removing various toxic contaminants, particularly oil-contaminated soil (i.e., total petroleum hydrocarbon). However, previous studies mainly tested the performance of laccase under irrelevant environmental conditions (i.e., artificially contaminated soil) with a limited number of soil samples, which can lead to bias optimization results for assessing laccase performance. Two types of natural oil-contaminated soils were tested under various reaction times and various concentrations of laccase extracted from Marasmiellus palmovorus. In addition, response surface methodology was used to find the maximum degradation of total petroleum hydrocarbon (TPH). The maximum degradation of TPH from soil A and soil B were 48.57% and 54.1%, respectively. Moreover, the performance of the laccase enzyme for oil recovery was also tested, with the percentage of oil recovery being 9.89% and 10.1 % for soil A and soil B, respectively. SARA fraction analysis indicated that laccase enzyme preferentially degraded highly polar SARA fraction (i.e., asphaltene and resin). In general, the application of laccase for the enzymatic remediation of oil-contaminated soils was practical. Hence, the use of laccase for environmental application is still promising.

Population dynamics and crude oil degrading ability of bacterial consortia of isolates from oil-contaminated sites in Nigeria.

Application of bacterial consortium of hydrocarbon degraders to crude oil-contaminated site can enhance bioremediation. This study evaluated the population dynamics and crude oil degradation abilities of various consortia developed from bacterial strains isolated from crude oil-contaminated sites using crude oil-supplemented Bushnell Haas media. Each consortium consisted of three bacterial strains and was designated as Consortium A (Serratia marcescens strain N4, Pseudomonas aeruginosa strain N3R, Pseudomonas aeruginosa strain W11), B (Pseudomonas aeruginosa strain N3R, Pseudomonas aeruginosa strain W11, Pseudomonas protegens strain P7), C (Serratia marcescens strain N4, Pseudomonas aeruginosa strain W11, Pseudomonas protegens strain P7), and D (Pseudomonas aeruginosa strain W15, Providencia vermicola strain W8, Serratia marcescens strain W13). There was progressive decline in the populations of Serratia marcescens strains in the consortia as the incubation period progressed. This may have led to reduction in their synergistic contribution and, subsequently, total degradation ability of crude oil by the consortia. The gravimetric analyses showed that Consortium D produced the highest % crude oil degradation of 29.66% compared to Consortia A, B, and C with 23.73%, 11.86%, and 19.49% respectively. Based on gas chromatography-mass spectrometry analyses, Consortium D produced the highest percentage total petroleum hydrocarbon degradation of 73.65% compared to 68.24%, 68.94%, and 69.19% produced by Consortia A, B, and C respectively. The biodegradation potential of Consortium D also demonstrates the significance of using isolates from the same isolation site in development of consortium for bioremediation.

Assessing the degradation potential of light petroleum hydrocarbons using bacterial activity (Pseudomonas aeruginosa) and root exudate of Conocarpus (Conocarpus erectus)

Petroleum hydrocarbons are one of the most common environmental pollutants, leading to serious environmental problems; and phytoremediation is an environmentally friendly way to remove petroleum pollutants from the soil. This research was designed based on the relatively high salinity of Ahwaz soil, the resistance of Conocarpus to soil salinity, and the presence of Pseudomonas bacteria in most environments. The aim of this study was to assess the effect of Conocarpus erectus and Pseudomonas aeruginosa on the removal efficiency of total petroleum hydrocarbons (TPHs) from contaminated soils with Bangestan crude oil in the phytoremediation process during 275 days under non-laboratory condition. After pedological studies and the selection of evaporation pond in crude oil desalination plant with suitable conditions for phytoremediation, this study was conducted in a factorial experiment with two factors based on completely randomized design with three replications. The factors used in this experiment include the treatment types (plant, bacteria, plant–bacteria cultivated in the soil, and soil with no plant and bacteria (control)) and the concentration of contaminant (Bangestan crude oil) with 5 levels (0, 0.5, 1, 2.5 and 5 wt%). TPHs were measured in soil samples collected from the rhizosphere of Conocarpus using gas chromatography with a flame ionization detector (GC-FID). The degradation rate of TPHs in soil with Conocarpus, Pseudomonas, and Conocarpus-Pseudomonas was 38.1%, 35.95%, and 70.54%, respectively. The results of the experimental factors showed that although plant and bacteria individually had a positive effect on the degradation of TPHs, the combination of bacteria and plants led to a more positive and significant effect on the degradation of TPHs ( P < 0 . 05 ).

Preliminary insights about the treatment of contaminated marine sediments by means of bioslurry reactor: Process evaluation and microbiological characterization

Contaminated marine sediments represent a critical threat towards human health and ecosystems, since they constitute a potential reservoir of toxic compounds release. In the present study, a bioslurry reactor was studied for the treatment of real marine sediments contaminated by petroleum hydrocarbons. The experimental campaign was divided in two periods: in the first period, microcosm trials were carried out to achieve useful indicators for biological hydrocarbon removal from sediments. The microcosm trials highlighted that the inoculum of halotolerant allochthonous bacteria provided the highest performance followed by autochthonous biomass. Based on the achieved results, in the second experimental period a bioslurry reactor was started up, based on a semisolid stirred tank reactor (STR) operated in batch mode. The process performances have been evaluated in terms of total petroleum hydrocarbon (TPH) removal, coupled with the characterization of microbial community through a Next Generation Sequencing (NGS) and phytotoxicity tests through the Germination Index (GI) with Lepidium Sativum seeds. The achieved results showed good hydrocarbons removal, equal to 40%, with a maximum removal rate of 220 mgTPH kg-1 d-1, but highlighting that high contaminant concentrations might affect negatively the overall removal performance. In general, the observed results were encouraging towards the feasibility of biological treatment of marine sediments contaminated by hydrocarbons. The microbiological analysis allowed the identification of taxa most involved in the degradation of TPH, highlighting after the treatment a shift in the microbial community from that of the raw sediment.

Bio-enhanced removal of hydrocarbon contents from spent engine oil contaminated soil using Staphylococcus aureus and Bacillus cereus co-culture

&#x0D; &#x0D; &#x0D; The study assessed the removal of total petroleum hydrocarbon (TPH) and polyaromatic hydrocarbons (PAHs) from spent engine oil (SEO) contaminated soil through bioenhancement of bacteria isolated from SEO polluted soil. Sterilized soil was subjected to a three level of SEO contamination before the addition of sterilized biostimulants including powdered cow dung (CD), powdered cocoa pod husk (CPH) and compost (made from fresh CPH and CD). Bacterial inoculum being Staphylococcus aureus and Bacillus cereus co-culture (150 mL) was added to the mixture in polyethylene bags. It was a factorial experiment that was laid out in a completely randomized design (CRD). The TPH and PAHs were estimated in the first day, fifth week and the tenth week that the room incubation lasted. Results generated from the influence of biostimulants on TPH and PAHs degradation potential of the bacterial co-culture showed that degradation of the hydrocarbon contents was significantly enhanced (p &lt; 0.05). At the tenth week, compost enhanced the most TPH reductions (315 and 380 mg kg–1) compared with other biostimulants on 5% and 15% SEO contamination levels, respectively. Compost equally enhanced the most PAHs reductions (48.8, 39.6 and 94.6 mg kg–1) compared with other biostimulants on 5%, 10% and 15% SEO contamination levels respectively. However, the quantity of SEO contents degraded was significantly higher in the bioaugmented and biostimulated soil samples compared with the control employed. The technology adopted in this study can be effectively employed for the bioremediation of petroleum hydrocarbon related pollution.&#x0D; &#x0D; &#x0D;

Phytotoxicity of Salvinia molesta in Diesel Exposure

Phytoremediation is one of the methods to remove various types of pollutants from water and soil using plants. Salvinia molesta, an aquatic plant, is chosen in this study to determine its ability to degrade diesel as the pollutant in synthetic wastewater with different diesel concentrations (0, 8,700, 17,400, and 26,100 mg/L) for 14 days. Total petroleum hydrocarbon (TPH) has been used as an indicator to represent diesel concentration variation in wastewater. Degradation of TPH was 85.1% for diesel concentration of 8,700 mg/L, compared with only 53.9% in the corresponding control without plant. While, acute toxicity on S. molesta exposed in diesel concentrations of 17,400 and 26,100 mg/L was observed and eventually had caused the plants to die after 14 days of exposure. Additionally, throughout the phytotoxicity test, the biomass of S. molesta was found to fluctuate confirming inhibition on plant to survive with diesel contaminated water compared with the corresponding control without contaminant. Based on the results obtained it is suggested to decrease diesel concentration less than 8,700 mg/L in future study due to insolubility of diesel in water and the toxicity to the aquatic plants

Comparison of biodegradative efficiency of wildtype versus mutagenised Scenedesmus vacuolatus of spent coolant waste: dehydrogenase activity and total petroleum degradation studies

ABSTRACT This study aims to compare the biodegradability efficiency of spent coolant waste by wild-type microalga versus mutagenised Scenedesmus vacuolatus. The biodegradation efficiency of both groups microalgae was evaluated using dehydrogenase activity (DHA) and total petroleum hydrocarbon (TPH) degradation using gas chromatography and mass spectrometry (GCMS). The DHA of both microalgae was conducted in relation to the triphenyl formazan production (TPF). The TPH of extracellular hydrocarbon degradation and intracellular hydrocarbons were analysed using GCMS. The data obtained from DHA and GCMS were analysed using analysis of variance at a 5% level of significance (0 < 0.05). The wild-type and mutagenised S. vacuolatus showed biodegradation of spent coolant waste after five weeks. The highest TPF produced by wild-type microalgae after five weeks was 1.139 mg/mL ± 0.009. The highest TPF produced by mutagenised S. vacuolatus after five weeks was 1.771 mg/mL ± 0.006 which was 1.55-fold higher than the TPF produced by the wild-type microalgae in the treatment weeks. The highest TPH degraded by wild-type after five weeks was 85.87% ± 0.20, while the highest TPH degradation of 100% was observed for the mutagenised S. vacuolatus after five weeks of spent coolant waste treatment. These results suggest that the mutagenised S. vacuolatus was better in utilising and degrading spent coolant waste and, therefore, can be used to mitigate spent oil pollution.