Utilization Of Hydrocarbons Research Articles

Polycyclic Aromatic Hydrocarbons (PAHs) Biodegradation by Basidiomycetes Fungi, Pseudomonas Isolate, and Their Cocultures: Comparative In Vivo and In Silico Approach

The polycyclic aromatic hydrocarbons (PAHs) biodegradation potential of the five basidiomycetes' fungal monocultures and their cocultures was compared with that of a Pseudomonas isolate recovered from oil-spilled soil. As utilization of hydrocarbons by the microorganisms is associated with biosurfactant production, the level of biosurfactant production and its composition by the selected microorganisms was also investigated. The Pseudomonas isolate showed higher ability to degrade three of the five PAHs but the isolate did not produce biosurfactant higher than C. versicolor and P. ostreatus. Among the PAHs, the most effective biodegradation of PAH--pyrene (42%)--was obtained with the fungus C. versicolor. Cocultures involving the fungi and Pseudomonas could not significantly degrade the selected PAHs compounds above that degraded by the most efficient monoculture. A slight increase in pyrene degradation was observed in cocultures of C. versicolor and F. palustris (93.7% pyrene). The crude biosurfactant was biochemically characterized as a multicomponent surfactant consisting of protein and polysaccharides. The PAH biodegradation potential of the basidiomycetes fungi positively correlated with their potential to express ligninolytic enzymes such as lignin peroxidase (Lip), manganese peroxidase (Mnp), and laccase. The present study utilized in silico method such as protein-ligand docking using the FRED in Open Eye software as a tool to assess the level of ligninolytic enzymes and PAHs interactions. The in silico analysis using FRED revealed that of the five PAHs, maximum interaction occurred between pyrene and all the three ligninolytic enzymes. The results of the in silico analysis corroborated with our experimental results showing that pyrene was degraded to the maximum extent by species such as C. versicolor and P. ostreatus.

Preliminary identification of the bioremediation limiting factors of a clay bearing soil contaminated with crude oil

Bioremediation is an attractive alternative to treat soils contaminated with petroleum hydrocarbons. However, the effectiveness of biodegradation process can be limited by both contaminant characteristics and its bioavailability in soil. This work aims at establishing a preliminary procedure to identify the main factor (hydrocarbon recalcitrance or its bioavailability) that impairs the biodegradation, possibly resulting in low remediation efficiencies. Tests in soil microcosms were carried out applying biostimulation and bioaugmentation techniques. Similar experiments were conducted using liquid medium containing crude oil and microorganisms, both of them extracted from a weathered contaminated soil sample, nutrients and microbial inoculum constituted of Rhodoturula glutinis and Nocardia nova. After 30 days, highest microcosms biodegradation levels (98.8%) were obtained with bioaugmentation in liquid medium, pointing out that the main problem of petroleum hydrocarbon utilization by microorganisms was associated to its availability and not only to the intrinsic recalcitrancy of remaining pollutants.

Hydrocarbon Utilization by Nodule Bacteria and Plant Growth-Promoting Rhizobacteria

Standard and locally isolated nodule bacteria and plant growth-promoting rhizobacteria (PGPR) were grown on crude oil and individual pure hydrocarbons as sole sources of carbon and energy. The nodule bacteria included two standard Rhizobium leguminosarum strains, two standard Bradyrhizobium japonicum strains, and one unknown nodule bacterial strain that was locally isolated from Vicia faba nodules. The PGPR included one standard Serratia liquefaciens strain and two locally isolated strains of Pseudomonas aeruginosa and Flavobacterium sp. The pure hydrocarbons tested included n-alkanes with chain lengths from C9 to C40 and the aromatic hydrocarbons benzene, biphenyle, naphthalene, phenanthrene, and toluene. Quantitative gas liquid chromatographic analyses confirmed that pure cultures of representative nodule bacteria and PGPR could attenuate n-octadecane and phenanthrene in the surrounding nutrient medium. Further, intact nodules of V. faba containing bacteria immobilized on and within those nodules reduced hydrocarbon levels in a medium in which those nodules were shaken. It was concluded that legume crops are suitable phytoremediation tools for oily soil, since they enrich such soils not only with fixed nitrogen, but also with hydrocarbon-utilizing microorganisms. Further, legume nodules may have biotechnological value as materials for cleaning oily liquid wastes.

Anaerobic oxidation of short-chain hydrocarbons by marine sulphate-reducing bacteria

The short-chain hydrocarbons ethane, propane and butane are constituents of natural gas. They are usually assumed to be of thermochemical origin, but biological formation of ethane and propane has been also observed. Microbial utilization of short-chain hydrocarbons has been shown in some aerobic species but not in anaerobic species of bacteria. On the other hand, anaerobic utilization of short-chain hydrocarbons would in principle be expected because various anaerobic bacteria grow with higher homologues (> or =C(6)). Indeed, chemical analyses of hydrocarbon-rich habitats with limited or no access of oxygen indicated in situ biodegradation of short-chain hydrocarbons. Here we report the enrichment of sulphate-reducing bacteria (SRB) with such capacity from marine hydrocarbon seep areas. Propane or n-butane as the sole growth substrate led to sediment-free sulphate-reducing enrichment cultures growing at 12, 28 or 60 degrees C. With ethane, a slower enrichment with residual sediment was obtained at 12 degrees C. Isolation experiments resulted in a mesophilic pure culture (strain BuS5) that used only propane and n-butane (methane, isobutane, alcohols or carboxylic acids did not support growth). Complete hydrocarbon oxidation to CO2 and the preferential oxidation of 12C-enriched alkanes were observed with strain BuS5 and other cultures. Metabolites of propane included iso- and n-propylsuccinate, indicating a subterminal as well as an unprecedented terminal alkane activation with involvement of fumarate. According to 16S ribosomal RNA analyses, strain BuS5 affiliates with Desulfosarcina/Desulfococcus, a cluster of widespread marine SRB. An enrichment culture with propane growing at 60 degrees C was dominated by Desulfotomaculum-like SRB. Our results suggest that diverse SRB are able to thrive in seep areas and gas reservoirs on propane and butane, thus altering the gas composition and contributing to sulphide production.

Obligate oil-degrading marine bacteria

Over the past few years, a new and ecophysiologically unusual group of marine hydrocarbon-degrading bacteria - the obligate hydrocarbonoclastic bacteria (OHCB) - has been recognized and shown to play a significant role in the biological removal of petroleum hydrocarbons from polluted marine waters. The introduction of oil or oil constituents into seawater leads to successive blooms of a relatively limited number of indigenous marine bacterial genera--Alcanivorax, Marinobacter, Thallassolituus, Cycloclasticus, Oleispira and a few others (the OHCB)--which are present at low or undetectable levels before the polluting event. The types of OHCB that bloom depend on the latitude/temperature, salinity, redox and other prevailing physical-chemical factors. These blooms result in the rapid degradation of many oil constituents, a process that can be accelerated further by supplementation with limiting nutrients. Genome sequencing and functional genomic analysis of Alcanivorax borkumensis, the paradigm of OHCB, has provided significant insights into the genomic basis of the efficiency and versatility of its hydrocarbon utilization, the metabolic routes underlying its special hydrocarbon diet, and its ecological success. These and other studies have revealed the potential of OHCB for multiple biotechnological applications that include not only oil pollution mitigation, but also biopolymer production and biocatalysis.

Combustion characteristics of vacuum residue in a test furnace and its utilization for utility boiler

Recently, increased attention has been exerted on the utilization of cheaper hydrocarbons fuel such as Vacuum Residue (VR). As a fundamental investigation for VR utilization, VR combustion tests were carried out in a test furnace with a fuel feed rate of 20 kg/h. As compared with heavy oil, VR used in this work is much more viscous and contains high percentages of sulfur, carbon residue and heavy metals. Successful fuel transportation and atomization has been achieved with the indirect heating of fuel by a thermia oil. The measured distributions of temperature, major species concentrations and solid samples along with the furnace revealed that the main reaction zone remains within about 1 m from the burner tip and the characteristics of VR flame are dependent on the ratio of fuel/air feeding rate. VR carbonaceous particles collected along with the furnace showed that their complete conversion would be a very essential factor for the utilization of VR as a fuel. Several issues for applying it to utility boilers have been investigated in line with the present results, and some suggestions have been made.

Recent progress in SOFC anodes for direct utilization of hydrocarbons

There would be significant advantages to having anodes for solid oxide fuel cells (SOFCs) that were capable of directly utilizing hydrocarbon fuels. Because conventional Ni-based anodes catalyze the formation of carbon fibers, new anode compositions are required for this application, but most of the materials that have been proposed exhibit either limited thermal stability or poor electrochemical activity. In this paper, we will describe two strategies for the development of new anodes with improved performance. The first strategy involves the use of bimetallic compositions with layered microstructures. In the bimetallic anodes, one metal is used for thermal stability while the other provides the required carbon tolerance. The second strategy involves separating the anode into two layers: a thin functional layer for electrocatalysis and a thicker conduction layer for current collection. With this approach, the functional layer can be optimized for catalytic activity and, if it is thin enough, requires minimal conductivity. Examples are shown for each of these approaches and possible future directions are outlined.

Time-dependent stability of used engine oil degradation by cultures of Pseudomonas fragi and Achromobacter aerogenes

Pseudomonas fragi and Achromobacter aerogenes isolated from used engine oil polluted soils were grown in minimal salts medium (MSM) supplemented with used engine oil as sole carbon and energy source to evaluate their ability to biodegrade used engine oil. The two organisms utilized 73.3 and 80.0% of the oil with a degradation rate of 0.073 and 0.08 ml/day respectively. The utilization rate of the mixed culture did not differ significantly with an 80.0% utilization and 0.08 ml/day degradation rate. However the rate of utilization was reduced significantly after repeated sub culturing of the organisms on nutrient agar for six months with percentage utilization dropping to 33.3, 26.7 and 30.0% respectively for A. aerogenes, P. fragi and the mixed culture. This suggests that the presence of hydrocarbons in the growth medium is necessary for the stability of hydrocarbon utilization potentials of the isolates.

Enzymatic and genetic profiles in environmental strains grown on polycyclic aromatic hydrocarbons

The possible generation of oxidative stress induced by aromatic hydrocarbon degradation suggests that ancillary enzyme activities could facilitate the utilization of polycyclic aromatic hydrocarbons as sole carbon source. To investigate the metabolic profiles of low molecular weight polycyclic aromatic hydrocarbon-degrading strains of Sphingobium chlorophenolicum, Rhodococcus aetherovorans, Rhodococcus opacus and Mycobacterium smegmatis, the determination of the activity of putative detoxifying enzymes (rhodanese-like and glutathione S-transferase proteins) was combined with genetic analyses. All the studied strains were able to utilize phenanthrene or naphthalene. Glutathione S-transferase activity was found in S. chlorophenolicum strains grown on phenanthrene and it was related to the presence of the bphK gene, since modulation of glutathione S-transferase activity by phenanthrene paralleled the induction of glutathione S-transferase transcript in the S. chlorophenolicum strains. No glutathione S-transferase activity was detectable in R. aetherovorans, R. opacus and in M. smegmatis strains. All strains showed 3-mercaptopyruvate:cyanide sulfurtransferase activity. A rhodanese-like SseA protein was immunodetected in R. aetherovorans, R. opacus and in M. smegmatis strains, where increase of 3-mercaptopyruvate:cyanide sulfurtransferase activity was significantly induced by growth on phenanthrene.

Studies on the utilization of petroleum hydrocarbon by microorganisms isolated from oil-contaminated soil

Five genera of crude oil utilizing microorganisms were isolated from oil-contaminated soil. The organisms were identified as Bacillus sp., Pseudomonas aeruginosa, Pseudomonas putida, Aspergillus niger and Mucor plumbus. The isolates were tested for their ability to utilize Bonny Light crude oil using the gravimetric method. The percentage oil utilization for all the isolates ranged between 60.53 and 80.27% after 28 days of incubation. P. putida gave the highest percentage utilization of 80.27% and a rate of utilization of 0.46 mg/ml/day. Increased percentage utilization of 81.58% and rate of utilization of 0.47 mg/ml/day was achieved by a co-culture of P. putida and M. plumbus. The results obtained in this study suggest that P. putida is preferable for treatment of oil spill incidents and that its co-culture with M. plumbus could enhance crude oil utilization. International Journal of Natural and Applied Sciences Vol. 1(2) 2005: 122-128

A study of thermal stability and methane tolerance of Cu-based SOFC anodes with electrodeposited Co

Cu-based, solid oxide fuel cell (SOFC) electrodes were modified by electrodeposition of Co. The addition of only 5 vol% Co by electrodeposition significantly improved the thermal stability compared to either Cu–ceria–YSZ, Cu–Co–ceria–YSZ, or Co–ceria–YSZ electrodes prepared only by impregnation with much higher metal loadings, demonstrating that electrodeposited metal layers form metal films with better connectivity. In the absence of Co, SEM showed structural changes in the impregnated Cu after heating to 1173 K in humidified H 2 and these changes caused large increases in the ohmic resistance of fuel cells, as measured by impedance spectroscopy. In contrast, the ohmic resistance of a cell with 13 vol% Cu, 9 vol% ceria, and 5 vol% Co increased only slightly after 48 h at 1173 K in humidified H 2. While a Co–ceria–YSZ composite was found to form large amounts of carbon upon exposure to dry CH 4 at 1073 K for 3 h, the Co–Cu–ceria–YSZ composites did not form measurable amounts of carbon for the same conditions. XPS results for a Cu foil with a 250-nm Co film demonstrated that Cu migrates to the surface of the Co upon heating above 873 K, forming a stable Cu layer that appears to be approximately one monolayer thick. The implication of these results for the development of practical SOFC electrodes for the direct utilization of hydrocarbons is discussed.

Utilization of monocyclic aromatic hydrocarbons individually and in mixture by bacteria isolated from petroleum-contaminated soil

The fate of benzene, ethylbenzene, toluene, xylenes (BTEX) compounds through biodegradation was investigated using two different bacteria, Ralstonia picketti (BP-20) and Alcaligenes piechaudii (CZOR L-1B). These bacteria were isolated from extremely polluted soils contaminated with petroleum hydrocarbons. PCR and Fatty Acid Methyl Ester (FAME) were used to identify the isolates. In this study, BTEX biodegradation, applied as a mixture or as individual compounds by the bacteria was evaluated. Both bacteria were shown to degrade each of the BTEX compounds individually and in mixture. However, Alcaligenes piechaudii was a better degrader of BTEXs both in the mixture and individually. Differences between BTEX biodegradation in the mixture and individually were observed, especially in the case of benzene. The degradation of all BTEXs in the mixture was lower than the degradation of individual compounds for both bacteria tested. In the all experiments, toluene and m + p- xylenes were better removed than the other BTEXs. No intermediates of biodegradation were detected. Biosurfactant production was observed by culture techniques. In addition, 3-hydroxy fatty acids, important in biosurfactant production, were observed by FAME analysis. The test results indicate that the bacteria could contribute to bioremediation of aromatic hydrocarbon pollution.

Comparative studies on crosslinked and uncrosslinked natural rubber biodegradation by Pseudomonas sp.

A comparative study on biodegradation of di-cumyl peroxide (DCP) crosslinked and uncrosslinked natural rubber by Pseudomonas sp. was carried out. Decrease in organic carbon content along with the changes in tensile strength of the treated rubber, both DCP crosslinked and uncrosslinked natural rubber, indicated rubber hydrocarbon utilization by the Pseudomonas sp. A decrease in 60.88% MPa and 41.66% MPa was observed after five month’s old treated uncrosslinked natural rubber and DCP crosslinked rubber, respectively. Biodegradation was more pronounced in natural uncrosslinked rubber, which was further confirmed by the formation of aldehydic compounds with decrease in CH 2 stretching frequencies.

Effect of organic nutrient on microbial utilization of hydrocarbons on crude oil contaminated soil

The effect of organic nutrient (poultry manure) on biodegradation of soil (5 kg) contaminated with crude oil (50 g) was investigated for seven weeks. Four different test options were prepared namely; (i) 100 g of contaminated soil + 30 g of poultry manure; (ii) 100 g of contaminated soil + 60 g of poultry manure; (iii) 100 g of contaminated soil + 90 g of poultry manure; (iv) 100 g of contaminated soil only (control). The microbial degradation was monitored by the measurement of total heterotrophic count (THC), hydrocarbon utilizing bacterial count (HUB) and gravimetric loss of the crude oil with time. The cumulative THC of 6.9x107, 9.0x107, 1.03x108 and 3.1x107 cfu/g were recorded for test options (i), (ii), (iii) and (iv), respectively. The hydrocarbon utilizing bacterial counts (HUB) were 1.68x105, 1.63x105, 1.9x105 and 4.8x104 cfu/g for tests options (i), (ii), (iii) and (iv), respectively. There was a corresponding gravimetric hydrocarbon loss of 40.0, 45.26, 49.47 and 29.47% for test conditions (i), (ii), (iii), and (iv), respectively. The results of the study suggest that addition of organic nutrient (especially 90 g poultry manure) will further enhance microbial utilization of hydrocarbons. Key words: Biodegradation, crude oil, poultry manure.

Effect of organic nutrient on microbial utilization of hydrocarbons on crude oil contaminated soil

The effect of organic nutrient (poultry manure) on biodegradation of soil (5 kg) contaminated with crude oil (50 g) was investigated for seven weeks. Four different test options were prepared namely; (i) 100 g of contaminated soil + 30 g of poultry manure; (ii) 100 g of contaminated soil + 60 g of poultry manure; (iii) 100 g of contaminated soil + 90 g of poultry manure; (iv) 100 g of contaminated soil only (control). The microbial degradation was monitored by the measurement of total heterotrophic count (THC), hydrocarbon utilizing bacterial count (HUB) and gravimetric loss of the crude oil with time. The cumulative THC of 6.9x107, 9.0x107, 1.03x108 and 3.1x107 cfu/g were recorded for test options (i), (ii),(iii) and (iv), respectively. The hydrocarbon utilizing bacterial counts (HUB) were 1.68x105, 1.63x105, 1.9x105 and 4.8x104 cfu/g for tests options (i), (ii), (iii) and (iv), respectively. There was a corresponding gravimetric hydrocarbon loss of 40.0, 45.26, 49.47 and 29.47% for test conditions (i),(ii), (iii), and (iv), respectively. The results of the study suggest that addition of organic nutrient (especially 90 g poultry manure) will further enhance microbial utilization of hydrocarbons

Effect of inorganic fertilizer on microbial utilization of hydrocarbons on oil contaminated soil

4cfu/g for tests options (i), (ii), (iii) and (iv), respectively. The corresponding gravimetric hydrocarbon losses were 40.0, 50.52, 36.84 and 29.47% for test conditions (i), (ii), (iii), and (iv), respectively. The results of the study suggest that addition of inorganic fertilizer (especially 60 g NPK agricultural fertilizer) will further enhance microbial utilization of hydrocarbons.

Utilization of petroleum hydrocarbons by Pseudomonas sp. and transformed E. coli

Our previous studies showed that the biodegradation of petroleum oil by a i>pseudomonas isolated from a petroleum-contaminated soil was instable. In this work, t is shown that when the isolates are immobilized on Perlite, they are more stable for oil egradation. Although the isolate did not have any chemotaxis to octadecane, dodecane and ctane but utilize octadecane and dodecane better than octane and it did not utilized exane, benzene, kerosene, pentane, heptane or thiophenol. The generation time for degradation of petroleum oil, dodecane and octadecane was 20, 22, and 25 h respectively. This phenotype was not transformed to Pseudomonas by conjugation even with lysozyme treatment, however the petroleum oil and octadecane utilization were transformed to E . coli by lysozyme treatment. The transformed E . coli lost the ability to use octadecane after three subcultures on nutrient broth and 34 generations. African Journal of Biotechnology Vol. 4 (2), pp. 172-176, 2005

Comparative studies on rubber biodegradation through solid-state and submerged fermentation

A comparative study on natural rubber (NR) biodegradation through solid-state fermentation (SSF) and submerged fermentation (SmF) has been carried out for both bacterial as well as fungal species. Changes in the organic carbon content along with the average molecular weight of the treated rubber samples indicated rubber hydrocarbon utilization and its degradation. Proportion of sol and gel content of the treated rubber also varied with the SmF and SSF treatment. Further, presence of aldehyde groups in the treated rubber indicated rubber biodegradation. The comparative results showed SSF to be a better treatment method for rubber biodegradation.

Description of Toluene Inhibition of Methyl Bromide Biodegradation in Seawater and Isolation of a Marine Toluene Oxidizer That Degrades Methyl Bromide

Methyl bromide (CH3Br) and methyl chloride (CH3Cl) are important precursors for destruction of stratospheric ozone, and oceanic uptake is an important component of the biogeochemical cycle of these methyl halides. In an effort to identify and characterize the organisms mediating halocarbon biodegradation, we surveyed the effect of potential cometabolic substrates on CH3Br biodegradation using a 13CH3Br incubation technique. Toluene (160 to 200 nM) clearly inhibited CH3Br and CH3Cl degradation in seawater samples from the North Atlantic, North Pacific, and Southern Oceans. Furthermore, a marine bacterium able to co-oxidize CH3Br while growing on toluene was isolated from subtropical Western Atlantic seawater. The bacterium, Oxy6, was also able to oxidize o-xylene and the xylene monooxygenase (XMO) pathway intermediate 3-methylcatechol. Patterns of substrate oxidation, lack of acetylene inhibition, and the inability of the toluene 4-monooxygenase (T4MO)-containing bacterium Pseudomonas mendocina KR1 to degrade CH3Br ruled out participation of the T4MO pathway in Oxy6. Oxy6 also oxidized a variety of toluene (TOL) pathway intermediates such as benzyl alcohol, benzylaldehyde, benzoate, and catechol, but the inability of Pseudomonas putida mt-2 to degrade CH3Br suggested that the TOL pathway might not be responsible for CH3Br biodegradation. Molecular phylogenetic analysis identified Oxy6 to be a member of the family Sphingomonadaceae related to species within the Porphyrobacter genus. Although some Sphingomonadaceae can degrade a variety of xenobiotic compounds, this appears to be the first report of CH3Br degradation for this class of organism. The widespread inhibitory effect of toluene on natural seawater samples and the metabolic capabilities of Oxy6 indicate a possible link between aromatic hydrocarbon utilization and the biogeochemical cycle of methyl halides.

Glucose And Hydrocarbon Utilization By Bacteria Isolated From Diesel Impacted Soil In The Niger Delta

Hydrocarbon utilizing bacteria were isolated from diesel impacted sites at the University of Port Harcourt using the vapour phase transfer method. The isolates were identified as Bacillus, Pseudomonas, Acinetobacter, Serratia, and Micrococcus species. Examination of cultures supplemented with glucose revealed that the total viable counts ranged from 1.7 x 104 to 5.9 x 105 cfu/ml. For cultures supplemented with kerosene the total viable counts ranged from 1.18 x 104 to 3.1 x 105 cfu/ml. Bacillus spp. and Micrococcus spp. gave the highest and lowest counts respectively in both media types within 96 h. The other isolates had counts in between these ranges in the respective supplemented media. The growth of the isolates in mineral salts solution supplemented with glucose or kerosene resulted in turbidity of the broth as compared to clear media solutions in controls. Higher turbidity was recorded in media supplemented with glucose than kerosene, and this was reflected in the total viable counts obtained. The ability of the bacterial isolates to utilize glucose and hydrocarbon as substrates for energy and carbon has beneficial application in bioremediation technology in the Niger Delta. KEY WORDS: Hydrocarbon utilization, glucose metabolism, bioremediation technology Global Journal of Pure and Applied Sciences Vol.11(2) 2005: 205-208