Hydrocarbons N-alkanes Research Articles

Distribution, migration, and segmented risk assessment of the total petroleum hydrocarbons in soil, groundwater, and soil gas at an oil refinery

In this study, the concentrations of six petroleum hydrocarbons (n-alkane hydrocarbons (total petroleum hydrocarbons [TPH] (C6-C9) and (C10-C40)), BTEX(benzene, toluene, ethylbenzene, m & p-xylene)) in 261 soil, 31 groundwater, and 4 soil gas samples were measured to determine their spatial distribution，migration patterns and human health risks. To assess the rationality of parameter selection, GS-MS (gas chromatography-mass spectrometry) method was used to analyze the chemical composition of TPH (C6-C9), shanghai local regulation was referenced to assess TPH (C10-C40) various segmentation health risks. The results revealed that the contaminants were mainly concentrated in the refining workshop and the storage tank. The pathway of steam invasion in soil gas and the CR (carcinogenic risk) and HQ (hazard quotient) assessment of benzene in soil gas were 0–4 and 1–3 orders of magnitude higher than those in soil. TPH (C6-C9) was more similar to the Total Petroleum Hydrocarbons (Aromatic Low) in RSL (Regional Screening Level). Aliphatic hydrocarbons [AHCs]. (C10-C12) had the highest non-carcinogenic risk among all TPH (C10-C40) parts. The present study provided a reference to accurately determine the toxicological parameters of TPH (C6-C9) and TPH (C10-C40) and to improve the BTEX risk assessment methods.

Thermal processing of plastic wastes for fuel

Plastic wastes rise annually as a result of the growing demand for synthetic materials, which contributes to their manufacture. There are four main ways to recycle waste polymer, with thermal treatment for fuel being the most favorable to the environment. In this study, the thermal processing of plastic wastes was investigated with an anaerobic pyrolysis apparatus, and their thermal degradation was evaluated by using the thermogravimetric apparatus.Additionally, the elemental composition was determined by an elemental analyzer, n-alkanes were identified by gas chromatography with flame ionization detection/electron capture detector (GC-FID/ECD), and the hydrocarbons functional group was analyzed by Fourier transform infrared spectroscopy (FTIR). We pyrolyzed the most widely utilized polymers, including polypropylene (PP), low-density polyethylene (LDPE), and high-density polyethylene (HDPE), at temperatures as elevated as 500°C to obtain plastic pyrolysis oil (PPO). Then PPO was distilled into initial boiling point (IBP)-200°C (gasoline-like fuel), 200-350°C (diesel-like fuel), and over 350°C fraction (residue), and the technical features of each fraction were compared to the MNS 0217:2006 and MNS 6861:2020 standards. Diesel-like fuel (DLF) derived from LDPE consists of the n-alkane hydrocarbons with C8–C23 identified by flame ionization detection (FID) data; C10–C17 represented more than 80% of them.The hydrotreatment results revealed that the diesel-like fraction's nitrogen (N) and sulfur (S) amounts could have reduced from 0.06% to 0.01% and from 0.78% to 0.29%, respectively. In conclusion, it could be done to generate a product with a more stable hydrocarbon content from plastic wastes for fuel.

Preservation of molecular fossils in carbonate concretions in cretaceous shales in the songliao basin, northeast China

Paleoenvironmental information is better preserved in carbonate concretions. In this study, carbonate concretions in the Cretaceous Nenjiang shale, Songliao Basin, were examined to determine whether molecular fossils reflective of the paleoenvironment were better preserved at these sites. Organic and inorganic geochemical characteristics of the concretions and surrounding rocks were analyzed using a series of techniques, including SEM, LA-ICP-MS, GC-MS-MS, and GC-IRMS. The concretions are composed of high content microcrystalline dolomite. The δ13Ccarb and δ18Ocarb values of the concretionary dolomite were significantly higher than those of the surrounding rocks. The dolomite show enrichment in the LREEs and have a negative Eu anomaly. The concretion biomarkers showed distribution characteristics similar to those of surrounding rocks. This suggested that the molecular fossils preserved in concretions were mainly inherited from surrounding rocks. However, the concretions contained more C27 sterane and hopanes, with the hopane/sterane ratio being significantly higher than that of surrounding rocks (1.49 v. 0.86). Moreover, the relative content of 2-methylhopane was 2.4–6.6 times that of the surrounding rocks. This indicated changes in the biological equilibrium of source organisms within and outside the concretions. It was possible that the unstable organic matter at the core increased the bacterial concentration and activity inside the concretions. Both the hydrogen index and biomarker-derived indicators implied that the transformation of organic matter in concretions was minimized when compared with their host rock. The isotope δ13C16-30 was 1‰–3‰ more prevalent in individual N-alkane hydrocarbons in the concretions than in surrounding rocks, likely owing to differences in lithology, bacterial action, and degree of weathering. The study concluded that carbonate concretions could preserve molecular fossils better than the surrounding rocks, and the in-depth organic geochemical analysis of concretions could provide a valuable reference for research into early life forms.

A Review on Michelia Champaca and Flowers

Michelia champaca Linn. Known as Champaca is Belonging to family of Magnoliaceae. It Consists of 12 genera and 220 species of evergreen trees and shrubs. In recent times there are several reports of medical specialty roles and activities of Michelia champaca and its active principles on the circulatory system, antipyretic, diuretic1.The Phytochemical analysis of the leaves and flowers of the plant showed the presence of alkaloids, tannins, glycosides, carbohydrates, amino acids, flavonoids and sterol in different solvent system. The petroleum ether extract of the dried flower contained n-alkane hydrocarbons, unsaturated aliphatic ketones, beta sistosterol and quercetin. The quercetin forms the first report of its occurrence in the genus Michelia(Shalini and Jaggi 2004) Lago et al (2009) reported that volatile oils contained six sesquiterpene hydrocarbons, four oxygenated sesquiterpenes and two aliphatic alcohols from water using dichloromethane solvent in leaves of M. champaca L. This article provides the collective information about the phytochemical constituents isolated from various parts of this plant used in a modern scenario for the treatment of various ailments like β-sitosterol, sesquiterpenes, parthenolide, dihydro parthenolide, gallic acid, quercetin, liriodenine, essential oils, starch, etc. Traditional uses of the plant in the treatment of various disease like rheumatism, gout, diuretic, febrifuge, etc..

Mature petroleum hydrocarbons contamination in surface and subsurface waters of Kızılırmak Graben (Central Anatolia, Turkey): Geochemical evidence for a working petroleum system associated with a possible salt diapir

Salt formations exist in Kızılırmak Graben (Central Anatolia, Turkey), which consists of volcano-sedimentary units, and it was stated in previous studies that these formations have a diapiric structure. The adjacent basin, Ayhan Basin, contains bituminous shale and operated coal deposits. For this reason, in this study, it is aimed to investigate the oil and gas potential of the Kızılırmak Graben by conducting TPH (Total Petroleum Hydrocarbons) analysis on the samples taken from natural cold-water resources by making use of the thought that hydrocarbon generation may come into existence from those units in the Ayhan basin. As a consequence of the analyses performed, hydrocarbons have been brought into the open in all the water samples. The organic geochemical methods have been used to find out the source of hydrocarbons determined in the water resources. The disclosed n-alkane hydrocarbons are the mature petroleum hydrocarbons derived from peat/coal type organic matter (Type III kerogen, gas-prone). These mature hydrocarbon-rich waters can be regarded as evidence for the availability of a working hydrocarbon system associated with possible salt diapir identified by using gravity and magnetic data obtained from the investigation area.

Unusual aliphatic hydrocarbon profiles at hydrothermal vent fields of the Central and Southeast Indian Ridges and Mid-Indian Basin

The hydrocarbon (n-alkane and n-alkene) distribution in deep seawaters of the Mid-Indian Basin (MIB) and hydrothermal vent sites of the Central (CIR) and Southeast Indian Ridges (SEIR) were investigated to understand the impact of hydrothermal activities in deep seawater organic matter. The distinguishing feature of the detected hydrocarbons was in a bimodal distribution with a strong predominance of even-numbered n-alkenes (C16:1-C34:1) maximizing at n-C16 or n-C18, and a series of n-alkane hydrocarbons ranging from C16–C35 with slightly high content in long chain par but without an even/odd carbon number preference. The mono-unsaturated aliphatics were generally 1–4 times higher than the saturated counterpart and exhibited more complex vertical variabilities. The higher content of aliphatics in deeper water, i.e., the signals at 2500 m from the CIR and the increasing tendency towards the bottom from the SEIR in the near vent field sites, indicate a potential hydrothermal contribution. Sulfate-reducing microorganisms of bacteria and archaeon in seawater and the hydrothermal system may be responsible for the distribution feature of the saturated or unsaturated hydrocarbons, but the possibility of abiogenic sources cannot be excluded. In addition, the hydrocarbon profiles recorded the organic debris mineralization in the subsurface coinciding with dramatically hydrographic variability. The present aliphatic profiles feature reflected the complex bio-geochemical process, a minor impact of hydrothermal activity on the hydrocarbon distributions and deep water circulations in the Indian Ocean.

Oil and gas exploration in Seferihisar Uplift (Western Turkey) containing an operable-size gold deposit: Geochemical evidence for the presence of a working petroleum system

In recent studies, the links between hydrocarbon accumulations and gold mineralizations have been examined. According to the results obtained from these studies, it has been reported that gold and hydrocarbons are carried and deposited by the same hydrothermal fluids. In the Seferihisar Uplift, the Efemcukuru Gold Operation possesses the largest proven gold reserves of Turkey. For this reason, in this study, it is aimed to investigate the oil and gas potential of the Seferihisar Uplift by conducting total petroleum hydrocarbons analyses on the samples taken from the natural cold-water resources. As a result of the analyses conducted, hydrocarbons have been detected in all the water samples. Organic geochemical methods have been used to determine the source of hydrocarbons detected in the water resources. The n-alkane hydrocarbons found in the water samples are the mature petroleum hydrocarbons, which are the geochemical evidence for a working petroleum system in the study area. Due to the presence of mature hydrocarbon-rich waters, the main structure in a maximum of 765 m depth determined in the study area according to gravity and magnetic data has a significant hydrocarbon potential to become an oil and/or gas reservoir.

Estimation of Viscosity of the N-Alkane (C1-C 4) in Bitumen System Using Adaptive Neuro-Fuzzy Interference System (ANFIS)

One of the important mechanisms in solvent-aided thermal recovery processes is viscosity reduction. Light n-alkane hydrocarbons are among the potential solvents for solvent-aided thermal recovery processes. In this study, the viscosity of C1- C4 n-alkanes in bitumen was investigated. Adaptive neuro-fuzzy interference system (ANFIS) was used for this aim. The result obtained by the ANFIS model analyzed with the statistical parameters (i.e., MSE, MEAE, MAAE, and R2) and graphical methods. Results show that the ANFIS has high capability to the prediction of solvent/bitumen mixture viscosity.

The Analysis of n-Alkane Hydrocarbons in the Sediment around the Coast of Makassar Using Mopi Indicator

This study aims to determine the content of n-alkanes in the sediment around the coast of Makassar using the MOPI (Marine Oil Pollution Index) indicator. The method includes the sediment sampling from nine different stations with the Phleger Corer Sampler in gravimetric analysis to identify the concentration of organic material extract and aliphatic fraction. To identify the characteristic of n-alkane hydrocarbons, gas chromatography of mass spectra method was applied. The results of the aliphatic fraction (F1) analysis of the coastal sediments which were contaminated with low biogenic - petrogenic have a MOPI scores of 3, which is supported by a high UCM (Unresolved Complex Mixture) and n-alkane identified between C1-C44. While the sediments that come from natural processes, pure - biogenic and biogenic, have MOPI scores ​​between 1 and 2. This is supported by the chromatogram profile with an area of ​​UCM generally smaller by n-alkanes identified between C15-C58

Phytochemical Screening on Champaka pushpam (Michelia champaca)

Michelia champaca Linn. Known as Champaca is Belonging to family of Magnoliaceae. It Consists of 12 genera and 220 species of evergreen trees and shrubs. In recent times there are several reports of medical specialty roles and activities of Michelia champaca and its active principles on the circulatory system, antipyretic, diuretic1. Flowers and the fruit in combination with other drugs are recommended as an antidote to snake and scorpion venoms. The Smell of flowers is a good stimulant. The flowers are expectorant and useful in cough and rheumatism.2 The Phytochemical analysis of the leaves and flowers of the plant showed the presence of alkaloids, tannins, glycosides, carbohydrates, amino acids, flavonoids and sterol in different solvent system. The petroleum ether extract of the dried flower contained n-alkane hydrocarbons, unsaturated aliphatic ketones, beta sistosterol and quercetin. The quercetin forms the first report of its occurrence in the genus Michelia(Shalini and Jaggi 2004) Lago et al (2009) reported that volatile oils contained six sesquiterpene hydrocarbons, four oxygenated sesquiterpenes and two aliphatic alcohols from water using dichloromethane solvent in leaves of M. champaca L.3

A Critical Analysis of Bio-Hydrocarbon Production in Bacteria: Current Challenges and Future Directions

As global fossil reserves are abruptly diminishing, there is a great need for bioenergy. Renewable and sustainable bioenergy products such as biofuels could fulfill the global energy demand, while minimizing global warming. Next-generation biofuels produced by engineered microorganisms are economical and do not rely on edible resources. The ideal biofuels are alcohols and n-alkanes, as they mimic the molecules in fossil fuels and possess high energy densities. Alcohols and n-alkane hydrocarbons (C2 to C18) have been produced using engineered microorganisms. However, it is difficult to optimize the complex metabolic networks in engineered microorganisms to obtain these valuable bio-hydrocarbons in high yields. Metabolic engineering results in drastic and adverse cellular changes that minimize production yield in microbes. Here, we provide an overview of the progress in next-generation biofuel (alcohols and n-alkanes) production in various engineered microorganisms and discuss the latest tools for strain development that improve biofuel production.

Oligomer-Specific, Short Chain Linear Alcohol Ethoxylate Quantification via Comprehensive Two-Dimensional Gas Chromatography

Non-ionic linear alcohol ethoxylated surfactants (LAEs) make up a broadly utilized class of compounds commonly employed in unconventional hydraulic fracturing activities. However, current detection and quantification methods fail to operate in relevant concentration ranges and are limited in specificity because of a lack of access to all analytical standards for individual LAE oligomers. Here, we present a novel extraction and quantification technique for aqueous samples containing both petroleum hydrocarbons and short chain LAEs with alkyl chain lengths of 6–10 carbons and 0–9 ethylene oxide groups. Using liquid–liquid extraction and two-dimensional gas chromatography with flame ionization detection, the method provided over 80 and 100% recovery of LAEs and n-alkane hydrocarbons, respectively. Individual LAE oligomers were quantified using calibration curves of n-alkanes and adjusted response factors based on the effective carbon number (ECN) concept, and we present a detailed framework for calculating E...

Mercury, n-alkane and unresolved complex mixture hydrocarbon pollution in surface sediment across the rural–urban–estuarine continuum of the River Clyde, Scotland, UK

ABSTRACTSurface sediments (n=85) from a 160-km river-estuarine transect of the Clyde, UK, were analysed for total mercury (Hg), saturated hydrocarbons and unresolved complex mixtures (UCMs) of hydrocarbons. Results show that sediment-Hg concentration ranges from 0.01 to 1.38mgkg–1 (mean 0.20mgkg–1) and a spatial trend in Hg-content low–high–low–high, from freshwater source, to Glasgow, to estuary, is evident. In summary, sediment-Hg content is low in the upper Clyde (mean of 0.05Hg mgkg–1), whereas sediments from the Clyde in urbanised Glasgow have higher Hg concentrations (0.04 to 1.26mgkg–1; mean 0.45mgkg–1), and the inner estuary sediments contain less Hg (mean 0.06mgkg–1). The highest mean sediment Hg (0.65mgkg–1) found in the outer estuary is attributed to historical anthropogenic activities. A significant positive Spearman correlation between Hg and total organic carbon is observed throughout the river estuary (0.86; P<0.001). Comparison with Marine Scotland guidelines suggests that no sites exceed the 1.5mgkg–1 criterion (Action Level 2); 22 fall between 0.25 and 1.5mgkg–1 dry wt. (Action Level 1) and 63 are of no immediate concern (<0.25mgkg–1 dry wt.). Saturated (n-alkane) hydrocarbons in the upper Clyde are of natural terrestrial origin. By contrast, the urbanised Glasgow reaches and outer estuary are characterised by pronounced and potentially toxic UCM concentrations in sediments (380–914mg/kg and 103–247mgkg–1, respectively), suggesting anthropogenic inputs such as biodegraded crude oil, sewage discharge and/or urban run-off.

Accumulation of petroleum hydrocarbons in intracellular lipid bodies of the freshwater diatom Synedra acus subsp. radians.

The accumulation of hydrophobic compounds by phytoplankton plays a crucial role in the biogeochemical cycle of persistent organic pollutants (POPs) in aquatic environments. We studied the accumulation of polycyclic aromatic hydrocarbons (PAHs) in the freshwater diatom Synedra acus subsp. radians during its cultivation with crude oil hydrocarbons, using epifluorescent and laser confocal microscopy as well as gas chromatography-mass spectrometry (GC/MS) analysis. Our results revealed that in the presence of crude oil or an extract of a crude oil/n-hexane solution (light oil), S. acus subsp. radians accumulated PAHs in its lipid bodies. During cultivation in the presence of a crude oil/n-hexane solution, the cells selectively accumulated C12-C18 alkanes, with a preference for C15 and C16 homologues. The length of n-alkane hydrocarbon chains accumulated in cells was similar to the acyl chains of fatty acids of the diatom. We therefore suggest that the insertion of n-alkanes into the membrane lipid bilayer promotes the transmembrane transport of PAH in diatoms. Our results confirm the hypothesis that diatoms play a role in the elimination of hydrophobic hydrocarbons from aquatic systems.

English

The surface composition and surface properties of water hyacinth (Eichhornia crassipes) root biomass were studied before and after extraction with dilute nitric acid and toluene/ethanol (2/1, v/v) followed by ethanol, using Fourier Transform Infra-red (FT-IR) spectroscopy, thermogravimetric analysis, x-ray diffraction, scanning electron microscopy. FT-IR absorption bands were obtained at 3421, 2855, 1457 and 1035 cm-1 (O-H stretch, C-H vibration, C-H asymmetric deformation, and C-O stretch, respectively) and 1508, 1541 and 1559 cm-1 (all aromatic skeletal vibrations characteristic of lignin), as well as a C=O carboxylate stretch vibrational band at 1654 cm-1. Scanning electron microscopy confirmed the root biomass to be amorphous and not to have a strongly structured surface. The dilute mineral acid and organic solvent treatment increased crystallinity. Thermogravimetric analysis Studies show that the treated biomass are more thermally stable than the untreated biomass. Data are presented showing that dilute mineral acid and organic solvent treatment resulted in a decrease in the amount of lignin in the biomass. The implications of the decrease in the percentage of lignin on the adsorption of volatile polar organic solvents and non-polar n-alkane hydrocarbons is discussed. Key words: Water hyacinth, biomass, surface composition, Fourier Transform Infra-red (FT-IR) spectroscopy, scanning electron microscopy, x-ray diffraction spectroscopy, thermo gravimetric analysis.

Bioaugmentation strategy employing a microbial consortium immobilized in chitosan beads for oil degradation in mesocosm scale

A bacterial consortium composed by four metagenomic clones and Bacillus subtilis strain CBMAI 707, all derived from petroleum reservoirs, was entrapped in chitosan beads and evaluated regarding hydrocarbon degradation capability. Experiments were carried out in mesocosm scale (3000L) with seawater artificially polluted with crude oil. At different time intervals, mesocosms were sampled and subjected to GC-FID and microbiological analyses, as total and heterotrophic culturable bacterial abundance (DAPI and CFU count), biological oxygen demand (BOD) and taxonomic diversity (massive sequencing of 16S rRNA genes). The results obtained showed that degradation of n-alkane hydrocarbons was similar between both treatments. However, aromatic compound degradation was more efficient in bioaugmentation treatment, with biodegradation percentages reaching up to 99% in 30days. Community dynamics was different between treatments and the consortium used in the bioaugmentation treatment contributed to a significant increase in aromatic hydrocarbon degradation.

Retardation of oil cracking to gas and pressure induced combination reactions to account for viscous oil in deep petroleum basins: Evidence from oil and n-hexadecane pyrolysis at water pressures up to 900 bar

This study reports a laboratory pyrolysis experimental study on oil and n-hexadecane to rationalise the thermal stability of oil in deep petroleum reservoirs. Using a 25ml Hastelloy pressure vessel, a 35° API North Sea oil (Oseberg) and n-hexadecane (n-C16), were pyrolysed separately under non-hydrous (20bar), low pressure hydrous (175bar) and high liquid water pressure (500 and 900bar) at 350°C for 24h. This study shows that the initial cracking of oil and n-hexadecane to hydrocarbon gases was retarded in the presence of water (175bar hydrous conditions) compared to low pressures in the absence of water (non-hydrous conditions). At 900bar water pressure, the retardation of oil and n-hexadecane cracking was more significant compared to 175bar hydrous and 500bar water pressure conditions. Combination reactions have been observed for the first time in pressurised water experiments during the initial stages of cracking, resulting in the increased abundance of heavier n-alkane hydrocarbons (>C20), the amount of unresolved complex material (UCM), as well as the asphaltene content of the oil. These reactions, favoured by increasing water pressure provide a new mechanism for rationalising the thermal stability of oils, and for producing heavy oils at temperatures above which biodegradation can occur. Indeed, we demonstrate that bitumen from the high pressure Gulf of Mexico basin has been formed from lighter oil components and it possesses similar characteristics to the laboratory oils generated.

Thermal properties of n-pentadecane, n-heptadecane and n-nonadecane in the solid/liquid phase change region

The thermal properties including the thermal conductivity (λ), the specific heat (cp), the melting and crystallization temperatures together with their corresponding transition heat enthalpies of the odd-numbered linear alkane hydrocarbons n-pentadecane, n-heptadecane and n-nonadecane were measured in both the solid and liquid phases using the transient hot wire and the differential scanning calorimetry (DSC) techniques. The obtained results were compared with available literature data. Discussions were based also on the X-ray diffraction spectra of the three n-alkanes carried out at different temperatures and including both solid and liquid phases. A discontinuity of λ is observed at the solid - liquid phase transition of the three n-alkane hydrocarbons.

English

The use of lignocellulosic fibres as biosorbents has both environmental and economic benefits. They are biodegradable, safe to use and most importantly renewable and less costly than synthetic fibres. The objectives of the present work were to study the performance of lignocellulosic fibres from water hyacinth ( Eichhornia crassipes ), a pervasive fresh water aquatic weed widely distributed in the tropics, as a biosorbent for n-alkane hydrocarbons, n-hexane to n-nonane. The free energy (ΔG a ), enthalpy (ΔH a ) and entropy (ΔS a ) for the adsorption of n-alkanes hexane to nonane on ground dried water hyacinth ( E. crassipes ) root biomass were studied between 40 and 70°C column temperature using inverse gas chromatography, before and after treatment of the root biomass with mineral acid and organic solvent. The free energy of adsorption (ΔG a ), enthalpy of adsorption (ΔH a ) and entropy of adsorption (ΔS a ) values of -20.42 to -35.992 kJ.mol -1 , -21.18 to -33.704 kJK -1 mol -1 and +0.0023 to +0.0041 kJ.mol -1 respectively, were obtained for the adsorption of the n-alkane series on untreated water hyacinth root biomass. Mineral acid and organic solvent treatment leads to greater adsorption bond strength, with ΔG a and ΔH a values of -36.08 to -38.52 kJ.mol -1 and -34.01 to -36.33 kJK-1mol -1 , respectively, after mineral acid treatment, and -40.98 to -46.7 kJ.mol -1 and -38.35 to -43.7 kJK -1 mol -1 , respectively, after organic solvent treatment. The results show that mineral acid and organic solvent treated water hyacinth root biomass has potential as biosorbent for the adsorption of volatile n-alkane hydrocarbons. Factors affecting the adsorbent-adsorbate interaction are discussed. Key words: Water hyacinth, inverse gas chromatography, adsorption free energy, adsorption enthalpy, hydrocarbons.

Impacts of endophyte infection of ryegrass on rhizosphere metabolome and microbial community

The use of grasses such as ryegrass and fescues infected with endophytic fungi of the Epichloë genus is widespread in New Zealand’s pastoral systems. Each endophyte–cultivar combination represents a distinctive genome–genome association, resulting in unique biological outcomes. The wider influence of these interactions on rhizosphere microbiology are not well characterised. This is important, because there may be opportunities or risks associated with selective disruption of the rhizosphere microbiota. We explored the interaction of two commercially used endophyte fungi, E. festucae var. lolii strains AR1 and AR37, within a genetically uniform breeding line of perennial ryegrass (Lolium perenne cv. Samson 11104) on the rhizosphere metabolome and the composition of the fungal, bacterial, and Pseudomonas communities. There were strong differences in the rhizosphere metabolomes between infested and non-infested ryegrass strains (P = 0.06). These were attributed to shifts in various n-alkane hydrocarbon compounds. The endophyte-associated alteration in rhizosphere metabolome was linked to changes in the total bacterial (P < 0.01) and fungal (P < 0.05) rhizosphere communities. Furthermore, there was varying levels of support for endophyte-specific (AR1 v. AR37) impacts on the bacterial and fungal communities. Pseudomonas bacterial communities were not influenced by endophyte infection of ryegrass (P = 0.834).