Biodegradation Of Petroleum Hydrocarbons Research Articles

Evaluating the Impact of Nutrient Doses on Biostimulation of Petroleum Hydrocarbon Biodegradation in Cold Region Soils

Biostimulation by addition of nitrogen (N) and phosphorus (P) for enhancement of biodegradation of petroleum hydrocarbons in contaminated soils is a common practice in sub-Arctic (cold) regions. Based on the data reported in 58 peer-reviewed papers on hydrocarbon degradation in northern region soils, there was no identifiable optimal nutrient dose, although applied doses ranged over 3 orders of magnitude. Microcosm slurry biodegradation experiments conducted over a range of N (41 to 1350 mg/kg) and P (46 and 115 mg/kg) doses, using a northern site soil spiked with Arctic diesel, also showed comparable results. While addition of nutrients improved degradation extents, the degradation extents were not dependent on N and P doses. Biodegradation rate constants for C10–C16 and C16–C24 hydrocarbon fractions, however, showed the highest enhancements for the lowest N dose. Microbial community composition analysis based on 16S rRNA sequencing of DNA extracted from microcosms amended with only diesel, only nutrients, and both diesel and nutrients revealed that diesel enriched hydrocarbon degraders such as Pseudomonadaceae and Burkholderiaceae. Overall, our results and analyses show limited benefits of biostimulation of hydrocarbon degradation with high nutrient doses, and low nutrient doses are generally more or equally effective.

Activity of alkanmonooxygenase alkB gene in strains of hydrocarbon-oxidizing bacteria isolated from petroleum products.

Alkanmonooxygenase enzymes AlkB and Cyp153 are responsible for the aerobic degradation of n-alkanes of petroleum and petroleum products. To prove the usage of n-alkanes from oil and petroleum products by hydrocarbon-oxidizing bacteria isolated from aviation kerosene TS-1 and automobile gasoline AI-95, the detection of the key genes alkB, Alk1, Alk2, Alk3 and Cyp153 encoding alkanmonooxygenases AlkB and Cyp153 (responsible for the oxidation of hydrocarbons with a certain chain length) was carried out. It was found that bacterial strains isolated from TS-1 jet fuel, except Deinococcus sp. Bi7, had at least one of the studied n-alkane degradation genes. The strains Sphingobacterium multivorum Bi2; Alcaligenes faecalis Bi3; Rhodococcus sp. Bi4; Sphingobacterium sp. Bi5; Rhodococcus erythropolis Bi6 contained the alkB gene. In the strains of hydrocarbon-oxidizing bacteria isolated from gasoline AI- 95, this alkanmonooxygenase gene was not detected. Using the real-time PCR method, the activity of the alkB gene in all bacterial strains isolated from petroleum products was analyzed and the number of its copies was determined. By real-time PCR using a primer with a different sequence of nucleotides to detect the alkB gene, its activity was established in all bacterial strains isolated from gasoline AI-95; besides, the strain Paenibacillus agaridevorans Bi11 was assigned to the group with a high level of its activity (1290 copies/ml). According to the assessment of the growth of isolated hydrocarbon-oxidizing bacteria on a solid Evans mineral medium with the addition of the model mixture of hydrocarbons, the strains were divided into three groups. The distributions of strains of hydrocarbon-oxidizing bacteria in the groups based on the activity of the alkB gene and groups formed based on the growth ability and use of the model mixture of hydrocarbons and petroleum products were found to be consistent. The results obtained indicate that we need to use a complex of molecular and physiological methods for a comprehensive analysis of the distribution of the studied genes in bacteria and to assess their activity in the strains of hydrocarbon-oxidizing bacteria capable of biodegradation of petroleum hydrocarbons.

Biodegradation of Petroleum Hydrocarbons by Drechsleraspicifera Isolated from Contaminated Soil in Riyadh, Saudi Arabia.

Currently, the bioremediation of petroleum hydrocarbons employs microbial biosurfactants because of their public acceptability, biological safety, and low cost. These organisms can degrade or detoxify organic-contaminated areas, such as marine ecosystems. The current study aimed to test the oil-biodegradation ability of the fungus Drechslera spicifera, which was isolated from contaminated soil samples in Riyadh, Saudi Arabia. We used hydrocarbon tolerance, scanning electron microscopy, DCPIP, drop-collapse, emulsification activity, recovery of biosurfactants, and germination assays to assess the biodegradation characteristics of the D. spicifera against kerosene, crude, diesel, used, and mixed oils. The results of DCPIP show that the highest oxidation (0.736 a.u.) was induced by crude oil on the 15th day. In contrast, kerosene and used oil had the highest measurements in emulsification activity and drop-collapse assays, respectively. Meanwhile, crude and used oils produced the highest amounts of biosurfactants through acid precipitation and solvent extraction assays. Furthermore, the biosurfactants stimulated the germination of tomato seeds by more than 50% compared to the control. These findings highlight the biodegradation ability of D. spicifera, which has been proven in the use of petroleum oils as the sole source of carbon. That might encourage further research to demonstrate its application in the cleaning of large, contaminated areas.

Biotreatment of oily sludge by a bacterial consortium: Effect of bioprocess conditions on biodegradation efficiency and bacterial community structure.

We studied the biodegradation of oily sludge generated by a petroleum plant in Bahrain by a bacterial consortium (termed as AK6) under different bioprocess conditions. Biodegradation of petroleum hydrocarbons in oily sludge (C11-C29) increased from 24% after two days to 99% after 9 days of incubation in cultures containing 5% (w/v) of oily sludge at 40°C. When the nitrogen source was excluded from the batch cultures, hydrocarbon biodegradation dropped to 45% within 7 days. The hydrocarbon biodegradation decreased also by increasing the salinity to 3% and the temperature above 40°C. AK6 tolerated up to 50% (w/v) oily sludge and degraded 60% of the dichloromethane-extractable oil fraction. Illumina-MiSeq analyses revealed that the AK6 consortium was mainly composed of Gammaproteobacteria (ca. 98% of total sequences), with most sequences belonging to Klebsiella (77.6% of total sequences), Enterobacter (16.7%) and Salmonella (5%). Prominent shifts in the bacterial composition of the consortium were observed when the temperature and initial sludge concentration increased, and the nitrogen source was excluded, favoring sequences belonging to Pseudomonas and Stenotrophomonas. The AK6 consortium is endowed with a strong oily sludge tolerance and biodegradation capability under different bioprocess conditions, where Pseudomonas spp. appear to be crucial for hydrocarbon biodegradation.

Plant-derived saponin enhances biodegradation of petroleum hydrocarbons in the rhizosphere of native wild plants

Plant-derived saponins are bioactive surfactant compounds that can solubilize organic pollutants in environmental matrices, thereby facilitating pollutant remediation. Externally applied saponin has potential to enhance total petroleum hydrocarbon (TPH) biodegradation in the root zone (rhizosphere) of wild plants, but the associated mechanisms are not well understood. For the first time, this study evaluated a triterpenoid saponin (from red ash leaves, Alphitonia excelsa) in comparison to a synthetic surfactant (Triton X-100) for their effects on plant growth and biodegradation of TPH in the rhizosphere of two native wild species (a grass, Chloris truncata, and a shrub, Hakea prostrata). The addition of Triton X-100 at the highest level (1000 mg/kg) in the polluted soil significantly hindered the plant growth (reduced plant biomass and photosynthesis) and associated rhizosphere microbial activity in both the studied plants. Therefore, TPH removal in the rhizosphere of both plant species treated with the synthetic surfactant was not enhanced (at the lower level, 500 mg/kg soil) and even slightly decreased (at the highest level) compared to that in the surfactant-free (control) treatment. By contrast, TPH removal was significantly increased with saponin application (up to 60% in C. truncata at 1000 mg/kg due to enhanced plant growth and associated rhizosphere microbial activity). No significant difference was observed between the two saponin application levels. Dehydrogenase activity positively correlated with TPH removal (p < 0.001) and thus this parameter could be used as an indicator to predict the rhizoremediation efficiency. This work indicates that saponin-amended rhizoremediation could be an environmentally friendly and effective biological approach to remediate TPH-polluted soils. It was clear that the enhanced plant growth and rhizosphere microbial activity played a crucial role in TPH rhizoremediation efficiency. The saponin-induced molecular processes that promoted plant growth and soil microbial activity in the rhizosphere warrant further studies.

Идентификация источников нефтяных загрязнений методом инфракрасной спектроскопии

The article demonstrates the importance of using reliable methods for identifying oil pollution in relation to accidents and incidents at hazardous production facilities of oil and gas production. Examples are given and prospects for possible negative consequences of biosocial emergencies at drilling and production facilities of the oil and gas complex and related infrastructure are shown. The processes of temporary and biodegradation of petroleum hydrocarbons in soils and aquatic environment are described. The necessity of considering the processes of transformation of oils and oil products in the environment during the production of identification eco-forensic studies in relation to them is shown. The advantages of Fourier spectrometers are revealed, which allow reliably distinguish between oil samples with a difference in optical density in the spectra at the level of 0.01 (0.3–1 % transmission), compared with diffraction infrared spectrometers. Fourier spectrometers were used to study seven oil samples from various fields of the Khanty-Mansi Autonomous Okrug. The influence was assessed related to artificial aging on the possibility of identifying the source of oil origin in relation to samples collected in the places of pollution. The results of the study of samples extracted from oil-contaminated soil were carried out and presented. The results of the research confirm the possibility of creating a reliable method for identifying oil pollution based on the method of infrared spectroscopy, as well as new methodological approaches to the problem of identifying samples of oil products in the investigation of arson. It was determined that in the case of using modern technology based on Fourier spectrometers equipped with systems for automatic processing and comparison of spectra, the method of infrared spectroscopy can be used as not only a preliminary, but also one of the basic means of identification.

Biodegradation and Bioremediation of Petroleum Hydrocarbons in Marine Ecosystems by Microorganisms: A Review

Concern about increasing incidents of petroleum hydrocarbon spills and spillage into different marine environments is rising day by day due to enhanced human activities in marine water. The toxic compounds of spilled petroleum hydrocarbon in marine water lead to the immediate death of numerous marine organisms as well as initiate various vicious biogeochemical cycles in the marine environment resulting in prolonged toxic impacts on the marine environment. Recently, many sophisticated techniques, including physical methods, chemical methods, and biological methods, have been developed and adopted for the treatment of marine environments polluted with petroleum compounds. However, biological treatment is one of the most promising methods in this field by which microorganisms such as bacteria, fungi, and algae are used for biodegradation of pollutants such as the spilled petroleum hydrocarbon into neutralized or eco-friendly compounds. This review has been focused on different aspects of the pollution of the marine ecosystem by oil, mainly Petroleum hydrocarbons, the fate of spilled oil in marine environments and the role of microbial communities in it, as well as various techniques, especially the bioremediation and biodegradation of spilled oil including the factors affecting the capacity of techniques. Moreover, some future aspects of research in the field of biodegradation and bioremediation of spilled oil have been proposed.

Converging alfalfa (Medicago sativa L.) and petroleum hydrocarbon acclimated ACC-deaminase containing bacteria for phytoremediation of petroleum hydrocarbon contaminated soil

Plant assisted bioremediation of petroleum hydrocarbon contaminated soil is considered an effective green technology whereby accelerated degradation occurs due to converged effect of microorganisms and plants. However, survival and growth of microbes and plants under stress conditions is challenging task for success of the technology. In this study, plant growth promoting bacteria containing 1-aminocyclopropane-1-carboxylate (ACC)-deaminase activity and tolerance to petroleum hydrocarbon contamination were used in association with alfalfa for bioremediation of petroleum hydrocarbon contaminated soil. Eight pre-isolated bacterial isolates from soil having previous history of petroleum contamination were used in convergence with alfalfa on sand soil which was artificially contaminated (10 g crude oil per kg−1 of coarse textured soil). Combined effect of bacteria and plants on the degradation of petroleum hydrocarbons under controlled conditions of light and temperature was observed for a period of 60 days. The results of the study revealed that four bacterial isolates Bacillus subtilis strain PM32Y, Bacillus cereus strain WZ3S1, Bacillus sp. strain SM73 and Bacillus sp. strain WZ3S3 in association with alfalfa significantly degraded petroleum hydrocarbons. The most significant biodegradation (47%) of petroleum hydrocarbons was recorded in the experimental unit receiving PM32Y inoculation in association with alfalfa. Biodegradation of petroleum hydrocarbons was 33% with alone inoculation (without alfalfa) of PM32Y. The study revealed that combined use of bacteria and alfalfa plant is more efficient than alone application of either bacteria or plants for degradation of petroleum hydrocarbons.

Impacts of groundwater level fluctuation on soil microbial community, alkane degradation efficiency and alkane-degrading gene diversity in the critical zone: Evidence from an accelerated water table fluctuation simulation.

Petroleum hydrocarbons are hazardous to ecosystems and human health, commonly containing n-alkanes and polycyclic aromatic hydrocarbons. Previous researches have studied alkane degraders and degrading genes under aerobic or anaerobic conditions, but seldom discussed them in the intermittent saturation zone which is a connective area between the vadose zone and the groundwater aquifer with periodic alteration of oxygen and moisture. The present study investigated the difference in alkane degradation efficiency, bacterial community, and alkane degrading gene diversity in aerobic, anaerobic, and aerobic-anaerobic fluctuated treatments. All biotic treatments achieved over 90% of n-alkane removal after 120days of incubation. The removal efficiencies of n-alkanes with a carbon chain length from 16 to 25 were much higher in anaerobic scenarios than those in aerobic scenarios, explained by different dominant microbes between aerobic and anaerobic conditions. The highest removal efficiency was found in fluctuation treatments, indicating an accelerated n-alkane biodegradation under aerobic-anaerobic alternation. In addition, the copy numbers of the 16S rRNA gene and two alkB genes (alkB-P and alkB-R) declined dramatically when switched from aerobic to anaerobic scenarios and oppositely from anaerobic to aerobic conditions. This suggested that water level fluctuation could notably change the presence of aerobic alkane degrading genes. Our results suggested that alkane degradation efficiency, soil microbial community, and alkane-degrading genes were all driven by water level fluctuation in the intermittent saturation zone, helping better understand the effects of seasonal water table fluctuation on the biodegradation of petroleum hydrocarbons in the subsurface environment.

A Review on Biotechnological Approaches Applied for Marine Hydrocarbon Spills Remediation.

The increasing demand for petroleum products generates needs for innovative and reliable methods for cleaning up crude oil spills. Annually, several oil spills occur around the world, which brings numerous ecological and environmental disasters on the surface of deep seawaters like oceans. Biological and physico-chemical remediation technologies can be efficient in terms of spill cleanup and microorganisms—mainly bacteria—are the main ones responsible for petroleum hydrocarbons (PHCs) degradation such as crude oil. Currently, biodegradation is considered as one of the most sustainable and efficient techniques for the removal of PHCs. However, environmental factors associated with the functioning and performance of microorganisms involved in hydrocarbon-degradation have remained relatively unclear. This has limited our understanding on how to select and inoculate microorganisms within technologies of cleaning and to optimize physico-chemical remediation and degradation methods. This review article presents the latest discoveries in bioremediation techniques such as biostimulation, bioaugmentation, and biosurfactants as well as immobilization strategies for increasing the efficiency. Besides, environmental affecting factors and microbial strains engaged in bioremediation and biodegradation of PHCs in marines are discussed.

Isolation and characterization of alkane hydrocarbons-degrading Delftia tsuruhatensis strain D9 from petroleum-contaminated soils

A bacterial strain from petroleum-contaminated soil in south-eastern Turkey was isolated and characterized to determine the potential of alkane hydrocarbon biodegradation. Phenotypic characteristics and the sequence analysis of the 16S rRNA gene revealed that the strain D9 is a member of the Delfitia genus and most similar to Delftia tsuruhatensis (100%). The optimum pH and temperature values for the growth of D. tsuruhatensis strain D9 were found to be 9.0-10.0 and 35°C, respectively. The strain was found to grow in some single, medium and long-chain hydrocarbons such as decane, hexadecane, and squalene, tested by short-time incubation in basal medium (BM) in the presence of 1% hydrocarbon concentrations under optimum conditions. After incubation for 3 days, 65% of the single hydrocarbon hexadecane was degraded by the D. tsuruhatensis strain D9, revealed by GC-MS analysis. The biodegradation of petroleum hydrocarbons by D. tsuruhatensis strain D9 isolated and characterized in the present study shows that it can be a good candidate in the bioremediation process.

Multiple Lines of Evidence for Estimating NSZD Rates Overlying a Shallow LNAPL Source Zone

AbstractQuantitative methods of monitoring natural source zone depletion (NSZD) via biodegradation of petroleum hydrocarbons (PHC) are required to investigate source zone longevity and guide long‐term management of PHC impacted sites. Vadose zone NSZD processes can be monitored using analysis of surficial CO2 effluxes, soil‐gas gradients, and thermal gradients. This study describes an applied research and development program conducted at a former refinery site over a 4‐year period (2015 to 2019) on quantitative technologies for evaluation of NSZD of PHC light nonaqueous phase liquid (LNAPL) present within a shallow soil zone. A multiyear study using discrete CO2 efflux measurements from dynamic closed chambers was compared with estimates obtained using static traps and continuous monitoring using forced diffusion (FD) technology. Thermistor strings along a transect were used to monitor hourly thermal gradients and assess NSZD rates using the temperature gradient method. Discrete soil‐gas data were used to quantify the vertical oxygen gradient to estimate NSZD rates using the concentration gradient method (CGM). Results of discrete and continuous monitoring methods provide estimates of monthly NSZD rates that range seasonally from 80 to 1300 US gal/acre/year using radiocarbon corrected CO2 efflux method for decane (C10H22) equivalent, 120 to 1600 US gal/acre/year using CGM (for wet to dry conditions) and 400 to 2000 US gal/acre/year using the temperature gradient method. Both seasonal temperature and precipitation fluctuations contribute to variability in rates. Continuous methods are shown to provide for improved resolution of temporal variability and seasonal estimates, although discrete methods provide for improved spatial quantification.

Taxonomic and functional trait-based approaches suggest that aerobic and anaerobic soil microorganisms allow the natural attenuation of oil from natural seeps

Natural attenuation, involving microbial adaptation, helps mitigating the effect of oil contamination of surface soils. We hypothesized that in soils under fluctuating conditions and receiving oil from seeps, aerobic and anaerobic bacteria as well as fungi could coexist to efficiently degrade hydrocarbons and prevent the spread of pollution. Microbial community diversity was studied in soil longitudinal and depth gradients contaminated with petroleum seeps for at least a century. Hydrocarbon contamination was high just next to the petroleum seeps but this level drastically lowered from 2 m distance and beyond. Fungal abundance and alpha-diversity indices were constant along the gradients. Bacterial abundance was constant but alpha-diversity indices were lower next to the oil seeps. Hydrocarbon contamination was the main driver of microbial community assemblage. 281 bacterial OTUs were identified as indicator taxa, tolerant to hydrocarbon, potentially involved in hydrocarbon-degradation or benefiting from the degradation by-products. These taxa belonging to lineages of aerobic and anaerobic bacteria, have specific functional traits indicating the development of a complex community adapted to the biodegradation of petroleum hydrocarbons and to fluctuating conditions. Fungi are less impacted by oil contamination but few taxa should contribute to the metabolic complementary within the microbial consortia forming an efficient barrier against petroleum dissemination.

Predicting Primary Biodegradation of Petroleum Hydrocarbons in Aquatic Systems: Integrating System and Molecular Structure Parameters using a Novel Machine-Learning Framework.

Quantitative structure–property relationship (QSPR) models for predicting primary biodegradation of petroleum hydrocarbons have been previously developed. These models use experimental data generated under widely varied conditions, the effects of which are not captured adequately within model formalisms. As a result, they exhibit variable predictive performance and are unable to incorporate the role of study design and test conditions on the assessment of environmental persistence. To address these limitations, a novel machine‐learning System‐Integrated Model (HC‐BioSIM) is presented, which integrates chemical structure and test system variability, leading to improved prediction of primary disappearance time (DT50) values for petroleum hydrocarbons in fresh and marine water. An expanded, highly curated database of 728 experimental DT50 values (181 unique hydrocarbon structures compiled from 13 primary sources) was used to develop and validate a supervised model tree machine‐learning model. Using relatively few parameters (6 system and 25 structural parameters), the model demonstrated significant improvement in predictive performance (root mean square error = 0.26, R 2 = 0.67) over existing QSPR models. The model also demonstrated improved accuracy of persistence (P) categorization (i.e., “Not P/P/vP”), with an accuracy of 96.8%, and false‐positive and ‐negative categorization rates of 0.4% and 2.7%, respectively. This significant improvement in DT50 prediction, and subsequent persistence categorization, validates the need for models that integrate experimental design and environmental system parameters into biodegradation and persistence assessment. Environ Toxicol Chem 2022;41:1359–1369. © 2022 ExxonMobil Biomedical Sciences, Inc. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

ITRAQ based characterization of proteomic change in petroleum hydrocarbon-degrading Pseudomonas aeruginosa in different pH conditions

In this study, a global proteomic change was characterized by iTRAQ analysis and bioinformatics analysis to study the influence by different pH conditions on proteins accumulation when Pseudomonas aeruginosa P6 degraded petroleum hydrocarbons. Compared with the condition of pH 7.2, 228 proteins in pH 5.0 and 93 proteins in pH 8.5 were identified as differentially accumulated proteins. The results further showed that in the condition of pH 5.0, fourteen chemotaxis-related proteins, two uptake-related proteins, two cytochromes, nineteen ABC transporters and five porins were downregulated, while two dioxygenases, five β-oxidation-related proteins and one acyl-CoA metabolism-related protein were upregulated. In the condition of pH 8.5, one fimbrial protein, one aldehyde dehydrogenase, eight ABC transporters and six porins were downregulated, while five terminal oxidation-related proteins, one alcohol dehydrogenase, one β-oxidation-related protein and one acyl-CoA metabolism-related protein were upregulated. The results indicated that in the condition of pH 5.0, chemotaxis and uptake of carbon, terminal oxidation of short-chain alkanes and transmembrane transport which are considered as key cellular processes in biodegradation of petroleum hydrocarbons in P.aeruginosa P6 may be disturbed. While in the condition of pH 8.5, the activity of transmembrane transport may decrease.

Biodegradation of Petroleum Hydrocarbons and The Factors Effecting Rate of Biodegradation

Biodegradation of Petroleum Hydrocarbons and The Factors Effecting Rate of Biodegradation

Biodegradation of petroleum hydrocarbons in a weathered, unsaturated soil is inhibited by peroxide oxidants

Field-weathered crude oil-containing soils have a residual concentration of hydrocarbons with complex chemical structure, low solubility, and high viscosity, often poorly amenable to microbial degradation. Hydrogen peroxide (H2O2)-based oxidation can generate oxygenated compounds that are smaller and/or more soluble and thus increase petroleum hydrocarbon biodegradability. In this study, we assessed the efficacy of H2O2-based oxidation under unsaturated soil conditions to promote biodegradation in a field-contaminated and weathered soil containing high concentrations of total petroleum hydrocarbons (25200 mg TPH kg−1) and total organic carbon (80900 mg TOC kg−1). Microcosms amended with three doses of 48 g H2O2 kg−1 soil (unactivated or Fe2+-activated) or 24 g sodium percarbonate kg−1 soil and nutrients did not show substantial TPH changes during the experiment. However, 7.6–41.8% of the TOC concentration was removed. Furthermore, production of DOC was enhanced and highest in the microcosms with oxidants, with approximately 20–40-fold DOC increase by the end of incubation. In the absence of oxidants, biostimulation led to > 50% TPH removal in 42 days. Oxidants limited TPH biodegradation by diminishing the viable concentration of microorganisms, altering the composition of the soil microbial communities, and/or creating inhibitory conditions in soil. Study’s findings underscore the importance of soil characteristics and petroleum hydrocarbon properties and inform on potential limitations of combined H2O2 oxidation and biodegradation in weathered soils.

Field Test of In Situ Groundwater Treatment Applying Oxygen Diffusion and Bioaugmentation Methods in an Area with Sustained Total Petroleum Hydrocarbon (TPH) Contaminant Flow

Contamination of groundwater by petroleum hydrocarbons is a widespread environmental problem in many regions. Contamination of unsaturated and saturated zones could also pose a significant risk to human health. The main purpose of the study was to assess the efficiency of biodegradation of total petroleum hydrocarbon (TPH) in situ, in an area with loam and sandy loam soils, and to identify features and characteristics related to groundwater treatment in an area with a persistent flow of pollutants. We used methods of biostimulation (oxygen as stimulatory supplement) and bioaugmentation to improve water quality. Oxygen was added to the groundwater by diffusion through silicone tubing. The efficiency of groundwater treatment was determined by detailed monitoring. Implementation of the applied measure resulted in an average reduction in TPH concentration of 73.1% compared with the initial average concentration (4.33 mg/L), and in the local area, TPH content was reduced by 95.5%. The authors hope that this paper will contribute to a better understanding of the topic of groundwater treatment by in situ biodegradation of TPH. Further studies on this topic are particularly needed to provide more data and details on the efficiency of groundwater treatment under adverse geological conditions.

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.

THE PETROLEUM HYDROCARBON BIOREMEDIATION PERFORMANCE BY INOCULATING CONSORTIUM PETROPHYLIC AND THE CHICKEN MANURE AMENDMENT

Biodegradation of petroleum hydrocarbons in a land-treatment bioremediation system requires an effective degrading microbes and optimum system conditions. The study aimed to obtain the characteristics of the interaction between the petrophylic consortium (Pseudomonas sp. and Aspergillus sp.) and the amendment of chicken manure and to obtain the optimum dose to increase the biodegradation rate of petroleum hydrocarbons, soil pH change, and increased the population petrophylic fungi. The experiment was carried out on a greenhouse scale, using a factorial randomized block design (RBD) with two factors and three replications. The first factor was the inoculation of the petrophylic consortium consisting of: (i) without Petrophylic, (ii) 1% Petrophylic, (iii) 3% Petrophylic, (iv) 5% Petrophylic. The second factor was the amendment of chicken manure, consisting of 3 levels: (i) without chicken manure, (ii) 2% chicken manure, and (iii) 4% chicken manure. The results showed that petrophylic consortium inoculation and chicken manure amendment did not show an interaction effect on increasing the rate of biodegradation of petroleum hydrocarbons, soil pH, and increasing the population of petrophylic fungi. Likewise, the effect of independent treatment could not increase the biodegradation rate and soil pH.But, the application of chicken manure increased growth of the petrophylic fungus population during the 4-week incubation time. However, increasing Petrophylic fungi population density did not show increasing in degrading petroleum hydrocarbons. The dose of chicken manure used has not been able to supply N and P nutrients to achieve optimal C: N: P ratio conditions for degrading hydrocarbons effectively, resulting the inoculated petrophylic could not degrade hydrocarbons maximally. Compatibility between consortium microbes members as a hydrocarbon-degrading agent is an important factor for achieving effectively bioremediation performance.