High-performance bacterium-enhanced dual-compartment microbial fuel cells for simultaneous treatment of food waste oil and copper-containing wastewater.

Microbial fuel cells (MFCs) use the metabolic actions of microorganisms in an anode chamber to convert the chemical energy from wastewater into electrical energy. To improve the MFC power generation performance and chemical oxygen demand (COD) removal efficiency, Stenotrophomonas acidaminiphila was added to the anode chamber of a dual-compartment MFC. In this process, Stenotrophomonas acidaminiphila promotes the degradation of macromolecules such as bis(2-ethylhexyl) phthalate in food waste oil. Additionally, the generated electrical energy reduced Cu2+ in the copper-containing wastewater in the cathode chamber to Cu monomers. The maximum power density of the MFC was 49.5 ± 3.5 mW/m2, the maximum removal efficiencies of COD and Cu2+ were 63.5 ± 5.8% and 96.5 ± 1.0%, respectively, and Cu2+ was reduced to brick-red Cu monomers. This study provides insights into the simultaneous implementation of food waste oil treatment and metal resource recovery.

Characterization of 2-phenanthroate:CoA ligase from the sulfate-reducing, phenanthrene-degrading enrichment culture TRIP.

Polycyclic aromatic hydrocarbons (PAHs) are chemically stable pollutants that are poorly degraded by microorganisms in anoxic sediments. The anaerobic degradation pathway of PAHs such as phenanthrene starts with a carboxylation reaction forming phenanthroic acid. In this study, we identified and characterized the next enzyme in the pathway, the 2-phenanthroate:CoA ligase involved in the ATP-dependent formation of 2-phenanthroyl-CoA from cell-free extracts of the sulfate-reducing enrichment culture TRIP grown anaerobically with phenanthrene. The identified gene sequence indicated that 2-phenanthroate:CoA ligase belongs to the phenylacetate:CoA ligase-like enzyme family. Based on the sequence, we predict a two-domain structure of the 2-phenanthroate:CoA ligase with a typical large N-terminal and a smaller C-terminal domain. Partial purification of 2-phenanthroate:CoA ligase allowed us to identify the coding gene in the genome. 2-Phenanthroate:CoA ligase gene was heterologously expressed in Escherichia coli. Characterization of the 2-phenanthroate:CoA ligase was performed using the partially purified enzyme from cell-free extract and the purified recombinant enzyme. Testing all possible phenanthroic acid isomers as substrate for the ligase reaction showed that 2-phenanthroic acid is the preferred substrate and only 3-phenanthroic acid can be utilized to a minor extent. This also suggests that the product of the prior carboxylase reaction is 2-phenanthroic acid. 2-Phenanthroate:CoA ligase has an optimal activity at pH 7.5 and is oxygen-insensitive, analogous to other aryl-CoA ligases. In contrast to aryl-Coenzyme A ligases reported in the literature, which need Mg2+ as cofactor, 2-phenanthroate:CoA ligase showed greatest activity with a combination of 5 mM MgCl2 and 5 mM KCl. Furthermore, a substrate inhibition was observed at ATP concentrations above 1 mM and the enzyme was also active with ADP. IMPORTANCE: Polycyclic aromatic hydrocarbons (PAHs) constitute a class of very toxic and persistent pollutants in the environment. However, the anaerobic degradation of three-ring PAHs such as phenanthrene is barely investigated. The initial degradation step starts with a carboxylation followed by a CoA­thioesterification reaction performed by an aryl-CoA ligase. The formation of a CoA-thioester is an important step in the degradation pathway of aromatic compounds because the CoA-ester is needed for all downstream biochemical reactions in the pathway. Furthermore, we provide biochemical proof for the identification of the first genes for anaerobic phenanthrene degradation. Results presented here provide information about the biochemical and structural properties of the purified 2­phenanthroate:CoA ligase and expand our knowledge of aryl-CoA ligases.

Novel, active, and uncultured hydrocarbon-degrading microbes in the ocean.

Given the vast quantity of oil and gas input to the marine environment annually, hydrocarbon degradation by marine microorganisms is an essential ecosystem service. Linkages between taxonomy and hydrocarbon degradation capabilities are largely based on cultivation studies, leaving a knowledge gap regarding the intrinsic ability of uncultured marine microbes to degrade hydrocarbons. To address this knowledge gap, metagenomic sequence data from the Deepwater Horizon (DWH) oil spill deep-sea plume was assembled to which metagenomic and metatranscriptomic reads were mapped. Assembly and binning produced new DWH metagenome-assembled genomes that were evaluated along with their close relatives, all of which are from the marine environment (38 total). These analyses revealed globally distributed hydrocarbon-degrading microbes with clade-specific substrate degradation potentials that have not been reported previously. For example, methane oxidation capabilities were identified in all Cycloclasticus. Furthermore, all Bermanella encoded and expressed genes for non-gaseous n-alkane degradation; however, DWH Bermanella encoded alkane hydroxylase, not alkane 1-monooxygenase. All but one previously unrecognized DWH plume member in the SAR324 and UBA11654 have the capacity for aromatic hydrocarbon degradation. In contrast, Colwellia were diverse in the hydrocarbon substrates they could degrade. All clades encoded nutrient acquisition strategies and response to cold temperatures, while sensory and acquisition capabilities were clade specific. These novel insights regarding hydrocarbon degradation by uncultured planktonic microbes provides missing data, allowing for better prediction of the fate of oil and gas when hydrocarbons are input to the ocean, leading to a greater understanding of the ecological consequences to the marine environment.IMPORTANCEMicrobial degradation of hydrocarbons is a critically important process promoting ecosystem health, yet much of what is known about this process is based on physiological experiments with a few hydrocarbon substrates and cultured microbes. Thus, the ability to degrade the diversity of hydrocarbons that comprise oil and gas by microbes in the environment, particularly in the ocean, is not well characterized. Therefore, this study aimed to utilize non-cultivation-based 'omics data to explore novel genomes of uncultured marine microbes involved in degradation of oil and gas. Analyses of newly assembled metagenomic data and previously existing genomes from other marine data sets, with metagenomic and metatranscriptomic read recruitment, revealed globally distributed hydrocarbon-degrading marine microbes with clade-specific substrate degradation potentials that have not been previously reported. This new understanding of oil and gas degradation by uncultured marine microbes suggested that the global ocean harbors a diversity of hydrocarbon-degrading bacteria, which can act as primary agents regulating ecosystem health.

Exploring the diversity and functional profile of microbial communities of Brazilian soils with high salinity and oil contamination.

Environmental pollution associated with the petroleum industry is a major problem worldwide. Microbial degradation is extremely important whether in the extractive process or in bioremediation of contaminants. Assessing the local microbiota and its potential for degradation is crucial for implementing effective bioremediation strategies. Herein, contaminated soil samples of onshore oil fields from a semiarid region in the Northeast of Brazil were investigated using metagenomics and metataxonomics. These soils exhibited hydrocarbon contamination and high salinity indices, while a control sample was collected from an uncontaminated area. The shotgun analysis revealed the predominance of Actinomycetota and Pseudomonadota, while 16S rRNA gene amplicon analysis of the samples showed Actinomycetota, Bacillota, and Pseudomonadota as the most abundant. The Archaea domain phylotypes were assigned to Thermoproteota and Methanobacteriota. Functional analysis and metabolic profile of the soil microbiomes exhibited a broader metabolic repertoire in the uncontaminated soil, while degradation pathways and surfactant biosynthesis presented higher values in the contaminated soils, where degradation pathways of xenobiotic and aromatic compounds were also present. Biosurfactant synthetic pathways were abundant, with predominance of lipopeptides. The present work uncovers several microbial drivers of oil degradation and mechanisms of adaptation to high salinity, which are pivotal traits for sustainable soil recovery strategies.

Edible plant oil (EPO)-consumption activity of the isolate Fusarium keratoplasticum EN01 and other relative Fusarium species.

Edible oil is used in humans' daily lives, and the degradation of edible oil is a key process in sewage water treatment and in compost production from food wastes. In this study, a mixed microbial strain EN00, which showed high edible plant oil (EPO)-consumption activity, was obtained from soil via enrichment cultivation. A fungal strain EN01 was isolated from EN00 and relegated to Fusarium keratoplasticum, based on the nucleotide sequences of the TEF1-α gene. Strain EN01 eliminated more than 90% of hydrophobic compounds from the medium containing 1.0% (w/v) EPO within 10 days at 30 °C. The rate of consumption of EPO by EN01 was comparable with that of EN00, suggesting that EN01 was the main microorganism involved in the EPO-consumption ability of EN00. Strain EN01 efficiently utilized EPO as a sole carbon source. The EPO-consumption rate of EN01 was highest among six tested strains of Fusarium solani species complex (FSSC), while two FSSC strains of F. mori and F. cuneirostrum, whose phylogenetic relationships were relatively distant from EN01, had little EPO-eliminating activity. This data implies that the potent EPO-eliminating activity is not general in FSSC strains but is restricted to selected members of this complex. EN01 showed good growth at 25-30 °C, in media with an initial pH of 4-10, and in the presence of 0-3% (w/v) sodium chloride. Although the safety including pathogenicity must be strictly evaluated, some FSSC strains including EN01 have potentials for use in the degradation and elimination of edible oil.

Application of oil-degrading agents consisted of thermophilic Bacillus subtilis and Bacillus glycinifermentans in food waste.

This work aims to investigate the effective removal of oil in food waste (FW). Two bacteria, Bacillus subtilis and Bacillus glycinifermentans, were obtained under high temperature conditions and named YZQ-2 and YZQ-5, respectively. The oil degradation rate of two bacteria was explored under different pH value, temperature, and NaCl concentration. In addition, the lipase and emulsifying activity were evaluated. The maximum oil degradation rate was 83.41 ± 0.86% and the maximum lipase activity reached 89.73 ± 20.89 U L-1 with YZQ-2. The fermentation broth of YZQ-2 displayed exceptional emulsification activity. Subsequently, YZQ-2 and YZQ-5 were added to aerobic FW composting. The moisture content of the compost treated with inoculated strains decreased at a faster rate during the first three days of composting. The microbial quantity increased rapidly in the first three days, and the oil degradation rate reached 39.96% after five days. Due to the excellent adaptability to high temperature and ability to degrade oil, strains YZQ-2 and YZQ-5 exhibit superior potential for various applications.

Characterization of the Mycoremediation of n-Alkanes and Branched-Chain Alkanes by Filamentous Fungi from Oil-Polluted Soil Samples in Kazakhstan.

For decades, researchers have focused on containing terrestrial oil pollution. The heterogeneity of soils, with immense microbial diversity, inspires them to transform pollutants and find cost-effective bioremediation methods. In this study, the mycoremediation potentials of five filamentous fungi isolated from polluted soils in Kazakhstan were investigated for their degradability of n-alkanes and branched-chain alkanes as sole carbon and energy sources. Dry weight estimation and gas chromatography-mass spectrometry (GC-MS) monitored the growth and the changes in the metabolic profile during degradation, respectively. Penicillium javanicum SBUG-M1741 and SBUG-M1742 oxidized medium-chain alkanes almost completely through mono- and di-terminal degradation. Pristane degradation by P. javanicum SBUG-M1741 was >95%, while its degradation with Purpureocillium lilacinum SBUG-M1751 was >90%. P. lilacinum SBUG-M1751 also exhibited the visible degradation potential of tetradecane and phytane, whereby in the transformation of phytane, both the mono- and di-terminal degradation pathways as well as α- and ß-oxidation steps could be described. Scedosporium boydii SBUG-M1749 used both mono- and di-terminal degradation pathways for n-alkanes, but with poor growth. Degradation of pristane by Fusarium oxysporum SBUG-M1747 followed the di-terminal oxidation mechanism, resulting in one dicarboxylic acid. These findings highlight the role of filamentous fungi in containing oil pollution and suggest possible degradation pathways.

Genomic and biotechnological potential of a novel oil-degrading strain Enterobacter kobei DH7 isolated from petroleum-contaminated soil.

In this study, a novel oil-degrading strain Enterobacter kobei DH7 was isolated from petroleum-contaminated soil samples from the industrial park in Taolin Town, Lianyungang, China. The whole genome of the strain was sequenced and analyzed to reveal its genomic potential. The oil degradation and growth conditions including nitrogen, and phosphorus sources, degradation cycle, biological dosing, pH, and oil concentration were optimized to exploit its commercial application. The genome of the DH7 strain contains 4,705,032 bp with GC content of 54.95% and 4653 genes. The genome analysis revealed that there are several metabolic pathways and enzyme-encoding genes related to oil degradation in the DH7 genome, such as the paa gene cluster which is involved in the phenylacetic acid degradation pathway, and complete degradation pathways for fatty acid and benzoate, genes related to chlorinated alkanes and olefins degradation pathway including adhP, frmA, and adhE, etc. The strain DH7 under the optimized conditions has demonstrated a maximum degradation efficiency of 84.6% after 14 days of treatment using synthetic oil, which comparatively displays a higher oil degradation efficiency than any Enterobacter species known to date. To the best of our knowledge, this study presents the first-ever genomic studies related to the oil degradation potential of any Enterobacter species. As Enterobacter kobei DH7 has demonstrated significant oil degradation potential, it is one of the good candidates for application in the bioremediation of oil-contaminated environments.

Microaerobic degradation of crude oil and long chain alkanes by a new Rhodococcus strain from Gulf of Mexico.

Bacterial degradation of crude oil is a promising strategy for reducing the concentration of hydrocarbons in contaminated environments. In the first part of this study, we report the enrichment of two bacterial consortia from deep sediments of the Gulf of Mexico with crude oil as the sole carbon and energy source. We conducted a comparative analysis of the bacterial community in the original sediment, assessing its diversity, and compared it to the enrichment observed after exposure to crude oil in defined cultures. The consortium exhibiting the highest hydrocarbon degradation was predominantly enriched with Rhodococcus (75%). Bacterial community analysis revealed the presence of other hydrocarbonoclastic members in both consortia. In the second part, we report the isolation of the strain Rhodococcus sp. GOMB7 with crude oil as a unique carbon source under microaerobic conditions and its characterization. This strain demonstrated the ability to degrade long-chain alkanes, including eicosane, tetracosane, and octacosane. We named this new strain Rhodococcus qingshengii GOMB7. Genome analysis revealed the presence of several genes related to aromatic compound degradation, such as benA, benB, benC, catA, catB, and catC; and five alkB genes related to alkane degradation. Although members of the genus Rhodococcus are well known for their great metabolic versatility, including the aerobic degradation of recalcitrant organic compounds such as petroleum hydrocarbons, this is the first report of a novel strain of Rhodococcus capable of degrading long-chain alkanes under microaerobic conditions. The potential of R. qingshengii GOMB7 for applications in bioreactors or controlled systems with low oxygen levels offers an energy-efficient approach for treating crude oil-contaminated water and sediments.

Characterization of pumilacidin, a lipopeptide biosurfactant produced from Bacillus pumilus NITDID1 and its prospect in bioremediation of hazardous pollutants.

Highly hydrophobic compounds like petroleum and their byproducts, once released into the environment, can persist indefinitely by virtue of their ability to resist microbial degradation, ultimately paving the path to severe environmental pollution. Likewise, the accumulation of toxic heavy metals like lead, cadmium, chromium, etc., in the surroundings poses an alarming threat to various living organisms. To remediate the matter in question, the applicability of a biosurfactant produced from the mangrove bacterium Bacillus pumilus NITDID1 (Accession No. KY678446.1) is reported here. The structural characterization of the produced biosurfactant revealed it to be a lipopeptide and has been identified as pumilacidin through FTIR, NMR, and MALDI-TOF MS. The critical micelle concentration of pumilacidin was 120 mg/L, and it showed a wide range of stability in surface tension reduction experiments under various environmental conditions and exhibited a high emulsification index of as much as 90%. In a simulated setup of engine oil-contaminated sand, considerable oil recovery (39.78%) by this biosurfactant was observed, and upon being added to a microbial consortium, there was an appreciable enhancement in the degradation of the used engine oil. As far as the heavy metal removal potential of biosurfactant is concerned, as much as 100% and 82% removal was observed for lead and cadmium, respectively. Thus, in a nutshell, the pumilacidin produced from Bacillus pumilus NITDID1 holds promise for multifaceted applications in the field of environmental remediation.

Long-term biodegradation of crude oil in high-arctic backshore sediments: The Baffin Island Oil Spill (BIOS) after nearly four decades.

With an on-going disproportional warming of the Arctic Ocean and the reduction of the sea ice cover, the risk of an accidental oil spill from ships or future oil exploration is increasing. It is hence important to know how crude oil weathers in this environment and what factors affect oil biodegradation in the Arctic. However, this topic is currently poorly studied. In the 1980s, the Baffin Island Oil Spill (BIOS) project carried out a series of simulated oil spills in the backshore zone of beaches located on Baffin Island in the Canadian High Arctic. In this study two BIOS sites were re-visited, offering the unique opportunity to study the long-term weathering of crude oil under Arctic conditions. Here we show that residual oil remains present at these sites even after almost four decades since the original oiling. Oil at both BIOS sites appears to have attenuated very slowly with estimated loss rates of 1.8-2.7% per year. The presence of residual oil continues to significantly affect sediment microbial communities at the sites as manifested by a significantly decreased diversity, differences in the abundance of microorganisms and an enrichment of putative oil-degrading bacteria in oiled sediments. Reconstructed genomes of putative oil degraders suggest that only a subset is specifically adapted for growth under psychrothermic conditions, further reducing the time for biodegradation during the already short Arctic summers. Altogether, this study shows that crude oil spilled in the Arctic can persist and significantly affect the Arctic ecosystem for a long time, in the order of several decades.

Oily bilge water treatment using indigenous soil bacteria: Implications for recycling the treated sludge in vegetable farming.

Hydrocarbon contamination from motorized vessels operating on seas threaten marine ecosystems and need to treated efficiently. A bilge wastewater treatment using indigenous bacteria isolated from oil contaminated soil was studied. Five bacterial isolates (Acinetobacter baumanni, Klebsiella aerogenes, Pseudomonas fluorescence, Bacillus subtilis and Brevibacterium linens) were isolated from port soil and used in the bilge water treatment. Their crude oil degradation abilities were first confirmed experimentally. The single species and the consortia of each two species were compared in an experiment where the conditions were first optimized. The optimized conditions were 40 °C, carbon source glucose, nitrogen source ammonium chloride, pH 8, and salinity 25%. Each of the species and each combination was able to degrade oil. K. aerogenes and P. fluorescence were the most efficient in reducing the crude oil concentration. The crude oil concentration was reduced from 290 mg/L to 23 mg/L and 21 mg/L, respectively. The respective values for the loss in turbidity were from 320 NTU to 29 mg/L and 27 NTU and for BOD loss from 210 mg/L to 18 mg/L and 16 mg/L. Mn was reduced from 25.4 mg/L to 1.2 mg/L and 1.0 mg/L, Cu from 26.8 mg/L to 2.9 mg/L and 2.4 mg/L, and Pb from 29.8 mg/L to 1.5 mg/L and 1.8 mg/L. The consortium of K. aerogenes and P. fluorescence in the bilge wastewater treatment reduced the crude oil concentration to 11 mg/L. After the treatment, the water was removed and the sludge was composted with palm molasses and cow dung. After 60 days of composting and inoculation with different bacterial consortia, the final product was used as a seedbed for vegetables. The compost with the consortium K. aerogenes and P. fluorescence promoted vegetable plant growth most and could be used in farming.

Evaluating the Optimal Oil Concentrations in the Startup Performance of a Membrane Bioreactor Treating Oily Noodle-soup Wastewater.

The discharge of high-strength oily wastewater adversely affects the environment; therefore, the treatment of wastewater containing fats, oils, and grease from the food industry is of importance. In this study, we used a membrane bioreactor (MBR) to treat Ramen noodle-soup wastewater, and we evaluated the optimal oil concentration in the wastewater for the startup of the MBR treatment in winter and summer. The MBR system had a sufficient startup in both seasons when fed with a 20-fold dilution of the original oily wastewater, containing approximately 950 to 1,200 mg/L oil and approximately 3,000 to 4,400 mg/L biological oxygen demand (BOD; BOD-SS load of 0.1 to 0.2 kg/kg/d). The reactor performance in winter were relatively stable during the operation. While, activated sludge microbes in summer were not highly active with a 40-fold dilution of wastewater, because of the decreased mixed liquor suspended solid concentration during the operation period. Population shifts in the sludge microbiome with increasing oil concentrations were analyzed using high-throughput sequencing, and the relative abundance of operational taxonomic units belonging to the phylum Bacteroidetes were highest in both winter and summer when fed with 20-fold dilution of the wastewater. In particular, the family Chitinophagaceae was dominant, with relative abundances of 13.5% in winter and 5.1% in summer, suggesting that this family may play important roles in the startup of a MBR treating the wastewater.

Chelativorans petroleitrophicus sp. nov., a paraffin oil-degrading bacterium isolated from a mixture of oil-based drill cuttings and paddy soil.

We isolated a paraffin oil-degrading bacterial strain from a mixture of oil-based drill cutting and paddy soil, and characterized the strain using a polyphasic approach. The Gram-positive, aerobic, rod-shaped and non-spore-forming strain (SCAU 2101T) grew optimally at 50 °C, pH 7.0 and 0.5 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequence indicated that the strain represented a distinct clade in the genus Chelativorans, neighbouring Chelativorans intermedius LMG 28482T (97.1 %). The genome size and DNA G+C content of the strain were 3 969 430 bp and 63.1 mol%, respectively. Whole genome based phylogenomic analyses showed that the average nucleotide identity and digital DNA-DNA hybridization values between strain SCAU 2101T and C. intermedius LMG 28482T were 77.5 and 21.2 %, respectively. The major respiratory quinone was Q-10. The dominant fatty acids were C19 : 0 cyclo ω8c (50.6 %), summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c; 22.5 %) and C18 : 0 (13.8 %). The polar lipids of the strain included phosphatidylethanolamine, phosphatidylmonomethylethanolamine, phosphatidylglycerol, phosphatidylcholine and diphosphatidylglycerol. Based on the results, strain SCAU 2101T was considered to represent a novel species in the genus Chelativorans, for which the name Chelativorans petroleitrophicus sp. nov. is proposed. The type strain is SCAU 2101T (= CCTCC AB 2021125T=KCTC 92067T).

Chemical conversions of free phytosterols during the bleaching of corn oil.

Phytosterols have health benefits; however, they are partially removed during the bleaching of corn oil. We evaluated the chemical conversion of free phytosterols (FPs) during bleaching. FP degradation accelerated with increased time and temperature, following a first-order kinetic model. In the n-heptane system, air and activated clay promoted the chemical conversion of the FPs. Sterenes formation was analysed under different conditions using a zero-order kinetic model. The apparent activation energies revealed sterene formation decreasing in the following order: campesta-3,5-diene ≈ stigmasta-3,5,22-triene > stigmasta-3,5-diene. Isomers of the above were not detected, indicating that these sterenes were the only primary products of FPs. The desorption test indicated that the FP loss from corn oil was not only due to FPs being adsorbed the activated clay, but also FPs adsorbed at acidic activated sites being degraded. This study presents a vital scientific foundation for retaining FPs to develop healthier and more nutritious oils.

Biodegradation of Oil by a Newly Isolated Strain Acinetobacter junii WCO-9 and Its Comparative Pan-Genome Analysis.

Waste oil pollution and the treatment of oily waste present a challenge, and the exploitation of microbial resources is a safe and efficient method to resolve these problems. Lipase-producing microorganisms can directly degrade waste oil and promote the degradation of oily waste and, therefore, have very significant research and application value. The isolation of efficient oil-degrading strains is of great practical significance in research into microbial remediation in oil-contaminated environments and for the enrichment of the microbial lipase resource library. In this study, Acinetobacter junii WCO-9, an efficient oil-degrading bacterium, was isolated from an oil-contaminated soil using olive oil as the sole carbon source, and its enzyme activity of ρ-nitrophenyl decanoate (ρ-NPD) decomposition was 3000 U/L. The WCO-9 strain could degrade a variety of edible oils, and its degradation capability was significantly better than that of the control strain, A junii ATCC 17908. Comparative pan-genome and lipid degradation pathway analyses indicated that A. junii isolated from the same environment shared a similar set of core genes and that the species accumulated more specific genes that facilitated resistance to environmental stresses under different environmental conditions. WCO-9 has accumulated a complete set of oil metabolism genes under a long-term oil-contamination environment, and the compact arrangement of abundant lipase and lipase chaperones has further strengthened the ability of the strain to survive in such environments. This is the main reason why WCO-9 is able to degrade oil significantly more effectively than ATCC 17908. In addition, WCO-9 possesses a specific lipase that is not found in homologous strains. In summary, A. junii WCO-9, with a complete triglyceride degradation pathway and the specific lipase gene, has great potential in environmental remediation and lipase for industry.

Reflecting the Quality Degradation of Engine Oil by the Thermal Diffusivity: Radiative and Nonradiative Analyses.

Ageing of engine oil is an important issue determining the engine life and performance. The present work attempts to delineate the ageing-induced changes in engine oil through the mode-mismatched dual-beam thermal lens (MMDBTL) technique and other conventional spectroscopic techniques. For the analyses, engine oil samples were collected after every 200 km of runtime. As the thermal diffusivity is related to the nonradiative deexcitation upon optical absorption, comprehensive radiative and nonradiative analyses were carried out. The Ultraviolet-Visible, Fourier transform infrared, and Nuclear magnetic resonance spectroscopic analyses point to the structural modification as a result of the breaking of the long-chain hydrocarbons into ketones, aldehydes, esters, and other compounds. This modifies the absorption pattern, which can also be understood from the nonlinear refractive index study using the Z-scan technique. The compositional variations associated with the degradation upon ageing, the length of the hydrocarbon chain, and the formation of newer molecules account for the enhancement of the thermal diffusivity revealed through the MMBDTL techniques. The complementary nature of the radiative and nonradiative emission is understood from the fluorescence study. Thus, the study reveals the possibility of thermal diffusivity measurement as an effective tool for the quality monitoring of engine oil.

The Effect of Deep Frying French Fries and Two Types of Iberian Pork on the Characteristics of Extra Virgin Olive Oil and the Fried Products.

Although deep frying is widely used, little is known about the effect of frying different meats on the frying oil. The aims of this study were to investigate whether the pork type influences the characteristics of the frying oil, to compare any effects with those of French fries, and to research whether the use of thermally damaged oil differentially affects those products. French fries and pork from pigs reared outdoors on acorns and grass (outdoor) or indoors on a concentrated feed (indoor) were deep-fried in either raw or previously heated olive oil. The type of product affected most color parameters, K268 and the α-tocopherol content of the oil. The frying of outdoor pork hardly affected the α-tocopherol content, whereas the frying of indoor pork and especially French fries caused a significant decrease. This suggests that the meat type should be considered when setting the frying lifespan of olive oil. Regarding the fried products, L*, moisture (only French fries) and the malondialdehyde (MDA) content (only indoor pork) were the only parameters affected by the previous oil damage. The outdoor pork was less susceptible to oxidation than the indoor pork when the oil was severely damaged. Therefore, pig outdoor-based systems based on antioxidant-rich diets might be convenient to maintain oxidation at the lowest level after frying.

Potential Use of Deep-Sea Sediment Bacteria for Oil Spill Biodegradation: A Laboratory Simulation.

Deep-sea sedimentary hydrocarbonoclastic bacteria are still not widely used in the bioremediation field, especially for crude oil spill biodegradation. This study utilized a mixed culture of Raoultella sp., Enterobacter sp., and Pseudomonas sp. isolated from deep-sea sediment to determine the abilities of bacteria to degrade petroleum hydrocarbons while incorporating environmental variations in a microcosm study. The oil biodegradation extent was determined by measuring the remaining oil and grease in the sample vials. The highest percentage of biodegradation was 88.6%, with a constant degradation rate of 0.399 day-1. GC-MS analysis showed that the most degradable compound in the oil samples was paraffin. This study also observed that microbial degradation was optimized within three days of exposure and that degradation ability decreased at 35 °C. The salinity variation effects were insignificant. Based on all analyses, deep-sea sediment bacteria have great potential in oil spill biodegradation in a microcosm scale.

Polyphasic Analysis Reveals Potential Petroleum Hydrocarbon Degradation and Biosurfactant Production by Rare Biosphere Thermophilic Bacteria From Deception Island, an Active Antarctic Volcano.

Extreme temperature gradients in polar volcanoes are capable of selecting different types of extremophiles. Deception Island is a marine stratovolcano located in maritime Antarctica. The volcano has pronounced temperature gradients over very short distances, from as high as 100°C in the fumaroles to subzero next to the glaciers. These characteristics make Deception a promising source of a variety of bioproducts for use in different biotechnological areas. In this study, we isolated thermophilic bacteria from sediments in fumaroles at two geothermal sites on Deception Island with temperatures between 50 and 100°C, to evaluate the potential capacity of these bacteria to degrade petroleum hydrocarbons and produce biosurfactants under thermophilic conditions. We isolated 126 thermophilic bacterial strains and identified them molecularly as members of genera Geobacillus, Anoxybacillus, and Brevibacillus (all in phylum Firmicutes). Seventy-six strains grew in a culture medium supplemented with crude oil as the only carbon source, and 30 of them showed particularly good results for oil degradation. Of 50 strains tested for biosurfactant production, 13 showed good results, with an emulsification index of 50% or higher of a petroleum hydrocarbon source (crude oil and diesel), emulsification stability at 100°C, and positive results in drop-collapse, oil spreading, and hemolytic activity tests. Four of these isolates showed great capability of degrade crude oil: FB2_38 (Geobacillus), FB3_54 (Geobacillus), FB4_88 (Anoxybacillus), and WB1_122 (Geobacillus). Genomic analysis of the oil-degrading and biosurfactant-producer strain FB4_88 identified it as Anoxybacillus flavithermus, with a high genetic and functional diversity potential for biotechnological applications. These initial culturomic and genomic data suggest that thermophilic bacteria from this Antarctic volcano have potential applications in the petroleum industry, for bioremediation in extreme environments and for microbial enhanced oil recovery (MEOR) in reservoirs. In addition, recovery of small-subunit rRNA from metagenomes of Deception Island showed that Firmicutes is not among the dominant phyla, indicating that these low-abundance microorganisms may be important for hydrocarbon degradation and biosurfactant production in the Deception Island volcanic sediments.