Innovative Culturomic Approaches and Predictive Functional Metagenomic Analysis: The Isolation of Hydrocarbonoclastic Bacteria with Plant Growth Promoting Capacity

Innovative culturomic approaches were adopted to isolate hydrocarbonoclastic bacteria capable of degrading diesel oil, bitumen and a selection of polycyclic aromatic hydrocarbons (PAH), e.g., pyrene, anthracene, and dibenzothiophene, from a soil historically contaminated by total petroleum hydrocarbons (TPH) (10,347 ± 98 mg TPH/kg). The culturomic approach focussed on the isolation of saprophytic microorganisms and specialist bacteria utilising the contaminants as sole carbon sources. Bacterial isolates belonging to Pseudomonas, Arthrobacter, Achromobacter, Bacillus, Lysinibacillus, Microbacterium sps. were isolated for their capacity to utilise diesel oil, bitumen, pyrene, anthracene, dibenzothiphene, and their mixture as sole carbon sources. Pseudomonas, Arthrobacter, Achromobacter and Microbacterium sps. showed plant growth promoting activity, producing indole-3-acetic acid and expressing 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activity. In parallel to the culturomic approach, in the microbial community of interest, bacterial community metabarcoding and predictive functional metagenomic analysis were adopted to confirm the potentiality of the isolates in terms of their functional representativeness. The combination of isolation and molecular approaches for the characterisation of a TPH contaminated soil microbial community is proposed as an instrument for the construction of an artificial hydrocarbonoclastic microbiota for environmental restoration.

Evaluation of the Effectiveness of the Biopreparation in Combination with the Polymer γ-PGA for the Biodegradation of Petroleum Contaminants in Soil

Biodegradation is a method of effectively removing petroleum hydrocarbons from the natural environment. This research focuses on the biodegradation of aliphatic hydrocarbons, monoaromatic hydrocarbons such as benzene, toluene, ethylbenzene, and all three xylene isomers (BTEX) and polycyclic aromatic hydrocarbons (PAHs) as a result of soil inoculation with a biopreparation A1 based on autochthonous microorganisms and a biopreparation A1 with the addition of γ-PGA. The research used biopreparation A1 made of the following strains: Dietzia sp. IN133, Gordonia sp. IN138 Mycolicibacterium frederiksbergense IN53, Rhodococcus erythropolis IN119, Rhodococcus sp. IN136 and Pseudomonas sp. IN132. The experiments were carried out in laboratory conditions (microbiological tests, respirometric tests, and in semi-technical conditions (ex-situ prism method). The biodegradation efficiency was assessed on the basis of respirometric tests, chromatographic analyses and toxicological tests. As a result of inoculation of AB soil with the biopreparation A1 within 6 months, a reduction of total petroleum hydrocarbons (TPH) (66.03%), BTEX (80.08%) and PAHs (38.86%) was achieved and its toxicity was reduced. Inoculation of AB soil with the biopreparation A1 with the addition of γ-PGA reduced the concentration of TPH, BTEX and PAHs by 79.21%, 90.19%, and 51.18%, respectively, and reduced its toxicity. The conducted research has shown that the addition of γ-PGA affects the efficiency of the biodegradation process of petroleum pollutants, increasing the degree of TPH biodegradation by 13.18%, BTEX by 10.11% and PAHs by 12.32% compared to pure biopreparation A1.

Environmental and ecotoxicological risk assessment of pollution with light crude oil for an oil exploatation field

Global development of transportation dependent on internal combustion engines, involves major increases in the consumption of fossil fuels obtained by extracting crude oil from depths by means of wells and refining it. In this context, protection of environment and groundwater quality is an increasingly difficult objective to maintain, requiring modern methods to address possible negative effects on the environment. The current research assesses the degree of eco-toxicological and environmental risk for an oil exploitation area in case of an accidental pollution scenario with crude oil. The entire risk spectrum was analysed through a set of qualitative and quantitative risk assessment tools to highlight and quantify the most important effects caused by petroleum products on biotope and biocenoses. The primary aim of the research is to identify vulnerable environmental reservoirs for accidental oil pollution and to establish the best tools to quantify the environmental and ecotoxicological risk of groundwater contamination. The results obtained from the area showed a low to medium risk of contamination of the saturated and unsaturated area with crude oil expressed as TPH (total petroleum hydrocarbons) and a low risk of contamination with volatile organic compounds type BTEX associated contamination of biocenoses that can directly or indirectly interact with potentially polluted areas.

A Study of Soil Pollution by Road Runoff

Road runoff, a representative non-point source pollution, is known to seriously deteriorate the river water quality. In order to prevent river contamination due to road runoff, road runoff is infiltrated into the soil along the river. However, road runoff containing high concentrations of heavy metals and total petroleum hydrocarbons (TPH) can cause soil pollution. In this study, soil samples were collected at the point where road runoff flows, and the concentrations of heavy metals, such as cadmium, lead, and zinc, and TPH in them were compared with that in uncontaminated soil. Consequently, the concentration of heavy metals in the soil into which the road runoff flows was up to 21 times higher than that of the nearby uncontaminated soil. In conclusion, the discharge of road runoff into the soil seriously pollutes the soil. Therefore, direct discharge of road runoff to soil should be prevented to prevent soil pollution.

Eutrophication and sediment–water exchange of total petroleum hydrocarbons and heavy metals of Hashilan wetland, a national heritage in NW Iran

The heavy metal(loid)s concentrations in water and sediments were analyzed in the Hashilan wetland to assess the spatial distribution, pollution status, fate, partitioning, and ecological risk and also to identify the heavy metal(loid)s sources in sediments using PMF (Positive Matrix Factorization) and APCs-MLR (absolute principal component score-multiple linear regression) receptor models. According to the pollution indices, (Ni, Cu, Cr, Mo), and (Zn, Cr, and Cu) are considered the most important pollutants in sediments and water, respectively. Ni, Cr, and Cu are the main contributors to ecological risks in sediments of some stations. The potential ecological risk assessment proposed low ecological risk in water of the study area. Higher distribution coefficient (Kp) values of Ni, Cr, Mn, Cu, Co, Pb, As, and Zn indicated the majority of these heavy metals present in the sediments; whereas, the majority of Cd concentration occurs in water. PMF and APCs-MLR results indicated the natural sources were the main factors affecting the concentrations of Ni, Cr, Zn, Al, Co, Fe, Pb, As, Cd and somewhat Cu. Mixed natural and agricultural activities are the main sources of Mo, and somewhat Cu. According to the results, there is low pollution of TPH (total petroleum hydrocarbons) in the sediment samples. Also, phosphate (PO42−) and nitrate (NO3−) concentrations were below the recommended permissible limits at all sampling sites except the S8 station for NO3−.

Total Petroleum Hydrocarbons Contamination of the Surface Water and Sediments of Orashi River, Engenni, Ahoada West, Rivers State, Nigeria

The level of contamination of Orashi River by total petroleum hydrocarbons were investigated through the collection of surface water samples and sediment samples from four locations along the river. Determination of the level of contamination was done with the use of gas chromatography-flame ionization detector after following laid down clean-up procedures. The results obtained showed that total petroleum hydrocarbons in the surface water were 10.913±2.2022mg/L, 7.645±2.683mg/L, 9.074±2.1654mg/L and 12.212±3.3034mg/L for stations 1, 2, 3 and 4 respectively with a mean value of 9.961±2.5885mg/L, while in the sediment samples concentration values recorded were 22.3925±5.2104mg/Kg, 35.1071±9.9652mg/Kg, 50.4431±15.9916mg/Kg and 29.3869±8.0410mg/Kg for stations 1, 2 3 and 4 respectively with a mean value of 34.3324±9.8021mg/Kg. The partition coefficient calculations revealed that the sediment phase is more stable for total petroleum hydrocarbons as compared to the water phase. The analysis of the randomly collected samples revealed that total petroleum hydrocarbons have contaminated the river and therefore adequate steps should be taken to remedy the present condition of the Orashi River in order to mitigate any probable rise in the quantity of total petroleum hydrocarbons in the river above allowable limit.

Anthropogenic effects on the marine environment adjacent to Palmer Station, Antarctica

Localized contamination from research-related activities and its effects on macrofauna communities in the marine environment were investigated at Palmer Station, a medium-sized Antarctic research station. Relatively low concentrations of polycyclic aromatic hydrocarbons (PAHs; 32–302 ng g-1) and total petroleum hydrocarbons (TPHs; 0.9–8.9 μg g-1) were detected in sediments adjacent to the sewage outfall and pier, where most human activities were expected to have occurred, and at even lower concentrations at two seemingly reference areas (PAHs 6–30 ng g-1, TPHs 0.03–5.1 μg g-1). Elevated concentrations of PAHs in one sample taken in one reference area (816 ng g-1) and polychlorinated biphenyls (353 ng g-1) and dichloro-diphenyl-trichloroethane (3.2 and 25.3 ng g-1) in two samples taken adjacent to the sewage outfall indicate spatial heterogeneity of localized sediment contamination. Limpet (Nacella concinna) tissues collected adjacent to Palmer Station had high concentrations of PAHs, copper, lead, zinc and several other metals relative to outlying islands. Sediment and limpet tissue contaminant concentrations have decreased since the early 1990s following the Bahía Paraíso spill. Natural sediment characteristics affected macrofaunal community composition more than contamination adjacent to Palmer Station, presumably because of the low overall contamination levels.

Soil Microcosms for Bioaugmentation With Fungal Isolates to Remediate Petroleum Hydrocarbon-contaminated Soil

The aim of this work was to isolate indigenous PAH degrading-fungi from petroleum contaminated soil and exogenous ligninolytic strains from decaying-wood, with the ability to secrete diverse enzyme activity. A total of ten ligninolytic fungal isolates and two native strains, has been successfully isolated, screened and identified. The phylogenetic analysis revealed that the indigenous fungi (KBR1 and KB8) belong to the genus Aspergillus niger and tubingensis. While the ligninolytic exogenous PAH-degrading strains namely KBR1-1, KB4, KB2 and LB3 were affiliated to different genera like Syncephalastrum sp, Paecilomyces formosus, Fusarium chlamydosporum, and Coniochaeta sp., respectively. Basis on the taxonomic analysis, enzymatic activities and the hydrocarbons removal rates, single fungal culture employing the strain LB3, KB4, KBR1 and the mixed culture (LB3+KB4) were selected to be used in soil microcosms treatments. The Total petroleum hydrocarbons (TPH), fungal growth rates, BOD5/COD ratios and GC-MS analysis, were determined in all soil microcosmos treatments (SMT) and compared with those of the control (SMU). After 60 days of culture incubation, the highest rate of TPH degradation was recorded in SMT[KB4] by approximately 92±2.35% followed by SMT[KBR1] then SMT[LB3+KB4] with 86.66±1.83% and 85.14±2.21%, respectively.

Presence of Hydrocarbon Degrading Bacteria in Contaminated Soil Collected From Various Fuel Station in Bhilai, Chhattisgarh

In this study, we isolated seven strains (termed BY1–7) from polluted soil at an oil station and evaluated their abilities to degrade total petroleum hydrocarbons (TPHs). Among 45 bacterial colonies one bacterial strain was identified based on the cultural, morphological and biochemical characteristics. The isolated bacterium was then subjected to a preliminary assessment of their crude oil after 48 hours of incubation on nutrient agar plates overlaid with 100 ML of petroleum crude oil, the zone of clearance was observed. The isolated bacteria showed 35% petrol degradation, whereas a relatively high oil degradation rate, almost 40% was observed when the bacterium was acclimatized. The selected bacterial strains crude oil resistance was analysed based on the growth ability on the crude oil containing mediums. This strain was identified as Brevibacterium brevis. After inoculation, growth ability was measured and the highest percentage of petrol degradation occurred at temperature 37 °C with the value 30.8%. Bacteria displaying such capabilities are often exploited for the bio-remediation of petroleum oil contaminated environments. Recently, microbial remediation technology has developed rapidly and achieved major gains. However, this technology is not omnipotent. It is affected by many environmental factors that hinder its practical application, limiting the large-scale application of the technology. Keywords: Petroleum hydrocarbon-degrading Bacteria, Petroleum oil, Bio-remediation, Bacterial consortia, Environmental factors, Enzymes.