In China, the crude oil supply is highly dependent on overseas countries, and thus strengthening crude oil self-sufficiency has become an important issue of the national energy security. Tertiary oil recovery, especially polymer flooding, has been widely applied in large oil fields in China, which can increase the recovery rate by 15%-20% compared with water flooding. However, the widely used oil flooding polymers show poor thermal stability and salinity tolerance, complicated synthesis ways of monomers, and environmental unfriendliness. Moreover, the polymer flooding induces problems including pore plugging, heterogeneity intensification, high dispersion of remaining oil resources, pressure rise in injection wells, and low efficiency circulation of injection medium, which restrict the subsequent recovery of old oil fields. Here, we systematically review the developing and current situations of polymer flooding, introduce the innovative biomanufacturing of oil flooding polymers and their monomers or precursors as well as low-cost bio-based chemical raw materials for multiple compound flooding. The comprehensive study of the relationships between microbial fermentation metabolites and polymer flooding will reveal the green and low-carbon paths for polymer flooding. Such study will enable the application of enzymes produced by microorganisms in polymer production and polymer plugging removal after polymer flooding as well as the application of microbial metabolites such as biosurfactants, organic acids, alcohols, biogas, and amino acids in enhancing oil recovery. This review suggests that incorporating biomanufacturing into polymer flooding will ensure the high productivity and stability for crude oil production in China.
Polymers/metabolism* ; China ; Petroleum ; Oil and Gas Fields

Petroleum hydrocarbon pollution has become one of the global environmental problems, posing a serious threat to the environment and human health. Microbial remediation plays an important role in the remediation of petroleum hydrocarbon-contaminated environment. Nevertheless, the stress factors present in the environment polluted by petroleum hydrocarbons limit the effectiveness of microbial remediation. This paper reviews the common stress factors in petroleum hydrocarbon-polluted environment and the response mechanisms of microorganisms to these factors. Furthermore, we introduce the methods to improve microbial tolerance, such as irrational modification, rational modification based on systems biology tools or tolerance mechanisms, and the construction of microbial consortia. The application of these methods is expected to improve the viability and remediation efficiency of microorganisms in petroleum hydrocarbon-contaminated environment and provide new perspectives and technical support for environmental remediation.
Biodegradation, Environmental ; Petroleum/metabolism* ; Hydrocarbons/isolation & purification* ; Bacteria/genetics* ; Environmental Pollutants/isolation & purification* ; Petroleum Pollution

Plastics are widely used in human daily life, which bring great convenience. Nevertheless, the disposal of a large amount of plastic wastes also brings great pressure to the environment. Polyethylene terephthalate (PET) is a polymer thermoplastic material produced from petroleum. It has become one of the most commonly used plastics in the world due to its durability, high transparency, light weight and other characteristics. PET can exist in nature for a long time due to its complex structure and the difficulty in degradation, which causes serious pollution to the global ecological environment, and threatens human health. The degradation of PET wastes has since become one of the global challenges. Compared with physical and chemical methods, biodegradation is the greenest way for treating PET wastes. This review summarizes the recent advances on PET biodegradation including microbial and enzymatic degradation of PET, biodegradation pathway, biodegradation mechanisms, and molecular modification of PET-degrading enzymes. In addition, the prospect for achieveing efficient degradation of PET, searching and improving microorganisms or enzymes that can degrade PET of high crystallinity are presented, with the aimto facilitate the development, application and molecular modification of PET biodegradation microorganisms or enzymes.
Humans ; Polyethylene Terephthalates/metabolism* ; Polymers ; Biodegradation, Environmental ; Petroleum

As a culinary and medicinal herb, rosemary is widely used. The present work aimed to investigate the effects of rosemary extracts on metabolic diseases and the underlying mechanisms of action. Liver cells stably expressing SREBP reporter were used to evaluate the inhibitory effects of different fractions of rosemary extracts on SREBP activity. The obese mice induced by Western-type diet were orally administered with rosemary extracts or vehicle for 7 weeks, the plasma and tissue lipids were analyzed. SREBPs and their target genes were measured by quantitative RT-PCR. We demonstrated that the petroleum ether sub-fraction of rosemary extracts (PER) exhibited the best activity in regulating lipid metabolism by inhibiting SREBPs, while water and n-BuOH sub-fraction showed the SREBPs agonist-effect. After PER treatment, there was a significant reduction of total SREBPs in liver cells. PER not only decreased SREBPs nuclear abundance, but also inhibited their activity, resulting in decreased expression of SREBP-1c and SREBP-2 target genes in vitro and in vivo. Inhibiting SREBPs by PER decreased the total triglycerides and cholesterol contents of the liver cells. In the mice fed with Western-type diet, PER treatment decreased TG, TC, ALT, glucose, and insulin in blood, and improved glucose tolerance and insulin sensitivity. Furthermore, PER treatment also decreased lipid contents in liver, brown adipose tissue, and white adipose tissue. Our results from the present study suggested that petroleum ether fraction of rosemary extracts exhibited the best potential of improving lipid metabolism by inhibiting SREBPs activity.
Alkanes ; chemistry ; Animals ; Cholesterol ; metabolism ; Hepatocytes ; drug effects ; metabolism ; Humans ; Hyperlipidemias ; drug therapy ; genetics ; metabolism ; Insulin ; metabolism ; Insulin Resistance ; Liver ; drug effects ; metabolism ; Male ; Mice ; Mice, Inbred C57BL ; Petroleum ; analysis ; Plant Extracts ; administration & dosage ; chemistry ; isolation & purification ; Rosmarinus ; chemistry ; Sterol Regulatory Element Binding Protein 1 ; genetics ; metabolism ; Sterol Regulatory Element Binding Protein 2 ; genetics ; metabolism

To explore new microbial resources in deep subsurface oil reservoirs, strain DL-7 was isolated with Hungate technology from oil reservoir water sampled from Dagang oilfield, China. Physiological and biochemical examinations showed that H2/CO2 is the unique substrate of the strain, which cannot metabolize formate, methanol, trimethylamine, acetate and other secondary alcohols. The optimum growth conditions were further identified to be 60 degrees C, pH 7.0-7.5 and 0.25% NaCl. Moreover, the strain cannot grow without yeast extract. Analysis of its 16S rRNA sequence indicated that a similarity of 99.7% presents between the strain and the model species M. marburgensis DSM2133T (X15364).
Hot Temperature ; Methanobacteriaceae ; classification ; genetics ; isolation & purification ; metabolism ; Methanol ; metabolism ; Methanomicrobiaceae ; genetics ; isolation & purification ; Petroleum ; microbiology ; Phylogeny ; RNA, Ribosomal, 16S ; genetics ; Water Microbiology

We used immobilized lipase from Candida sp. 99-125 to produce fatty acid methyl esters (FAMEs) from crude oil and methanol. We studied the effects of phospholipids on activity of immobilized lipase, reaction velocity, stability of immobilized lipase and the stability of immobilized lipase in crude and refined oil. Results showed that the activity of the lipase immersed in petroleum ether with 1% phospholipids dropped more quickly than the lipase in petroleum ether without phospholipids. When soybean oil was used without phospholipids as material, the FAMEs yield of 15 min was 26.2%, whereas the yield decreased to 12.4% when there were 5% phospholipids in the soybean oil. However when the phospholipids content was below 1%, the stability of the lipase did not change obviously. The lipase was stable when used to catalyze crude soybean oil and crude jatropha oil, after 10 cycles the FAMEs yield was still above 70%. This lipase showed great potential for industrial production of biodiesel from crude oil.
Biofuels ; analysis ; Candida ; enzymology ; metabolism ; Enzymes, Immobilized ; Fatty Acids ; metabolism ; Lipase ; metabolism ; Methanol ; metabolism ; Methyl Ethers ; metabolism ; Petroleum ; metabolism ; Phospholipids ; metabolism

Biodenitrogenation of petroleum oil was investigated by a previously isolated carbazole-degrader Pseudomonas sp. XLDN4-9. In a tetradecane-aqueous phase system, biodegradation of carbazole was enhanced by the presence of n-tetradecane. And strain XLDN4-9 was capable of absorbing 95.2% of 2 g/L carbazole dissolved in diesel within 15 hours. Significant denitrogentation of crude oil, diesel and lubricanting oil was detected by strain XLDN4-9. Removal of carbazole, methylcarbazole, and dimethylcarbazole in diesel was confirmed by using GC-MS. After 3 days, 99% of carbazole and 15% of dimethyl carbazole was degraded. And the removal rate of 1-, 2-, 3-, and 4-methyl carbazole was determined to be 63.4%, 87.6%, 78.4%, and 66.5% respectively.
Biodegradation, Environmental ; Carbazoles ; chemistry ; metabolism ; Gas Chromatography-Mass Spectrometry ; Petroleum ; metabolism ; Pseudomonas ; classification ; metabolism

OBJECTIVEThe wetland at Dalian Bay in the Northeast of China has been polluted by oil severely. The effect of various microbes and operation parameters on the bioremediation of oil-polluted wetlands at Dalian Bay was investigated and reported previously. In the study, other operation conditions related to the status of medium were investigated via statistical experimental design and analysis and a necessary information is involved to use micro-technology in the application.

METHODSThe method used involved the direct inoculation of selected bacteria, which were capable of degrading oil. The operation conditions were further optimized and evaluated by gravimetrical assay.

RESULTSThe optimal pH and temperature for the studied bacteria to degrade the existing oil pollutants were established as pH 8.0 and 27 degrees C. The mixed of various bacteria showed better results in terms of oil degradation than any single one. Among the selected four factors, disturbance, oxidant, nutrients, and biosurfactant, the former two contributed more impacts on the oil degradation in the early stage of process, while the latter two became the limiting factors in the late stage. Three sets of optimal conditions were obtained for each individual stage, but no one was suitable for the overall process.

CONCLUSIONThe study demonstrated the technical feasibility of using direct inoculation into the contaminated soil samples to remove oil pollutants. It suggested that the operation conditions should be monitored and adjusted during the different stages of bio-reactions in the process to achieve the best result of oil degradation.

Bacteria ; metabolism ; Biodegradation, Environmental ; China ; Ecosystem ; Hydrogen-Ion Concentration ; Oceans and Seas ; Petroleum ; metabolism ; Soil ; analysis ; Soil Pollutants ; chemistry ; metabolism ; Temperature

BACKGROUND: NAD(P)H:quinone oxidoreductase 1 (NQO1) is an important enzyme in the metabolism of xenobiotics. NQO1 609C -> T (NQO1*2) has been reported to be associated with reduced enzyme activity, benzene-induced hematotoxicity, and acute leukemia. Incidences of multiple myeloma show interethnic variation and exposure to asbestos, petroleum products, and diesel exhaust is a risk factor for multiple myeloma. We studied the associations of NQO1 polymorphism with multiple myeloma risk, stage, and prognostic factors (hemoglobin, calcium, beta2-microglobulin, M-protein and creatinine). METHODS: The frequency of NQO1 polymorphism was investigated in 117 myeloma patients and 166 controls. NQO1 genetic polymorphism was determined by TaqMan allelic discrimination assay. Prognostic factors were obtained from the patients' medical records. RESULTS: The frequencies of the NQO1*1/*1, *1/*2, and *2/*2 genotypes were 31.6%, 63.2%, and 5.1% in the patients, whereas the respective figures in the controls were 31.9%, 48.3%, and 19,9%. The frequency of NQO1*2/*2 was significantly lower in patients than in controls and the odds ratio (OR) was 0.24 (95% confidence interval: 0.01-0.68) to NQO1*1/*1 genotype, indicating a decreased risk for multiple myeloma. There were no significant differences in tumor stages and other prognostic factors among NQO1 genotypes. CONCLUSIONS: A risk for multiple myeloma decreased in NQO1*2/*2 genotype in Koreans. We report, for the first time, that NQO1 polymorphism is associated with multiple myeloma risk.
Asbestos ; Calcium ; Discrimination (Psychology) ; Genotype ; Humans ; Incidence ; Leukemia ; Medical Records ; Metabolism ; Multiple Myeloma* ; Odds Ratio ; Petroleum ; Polymorphism, Genetic ; Polymorphism, Single Nucleotide ; Risk Factors ; Vehicle Emissions ; Xenobiotics

The potential biodegradation of crude oil was assessed based on the development of a fermentative process with a strain of Pseudomonas aeruginosa which produced 15.4 g/L rhamnolipids when cultured in a basal mineral medium using glycerol as a sole carbon source. However, neither cell growth nor rhamnolipid production was observed in the comparative culture system using crude oil as the sole carbon source instead. As rhamnolipid, an effective biosurfactant, has been reported to stimulate the biodegradation of hydrocarbons, 1 g/L glycerol or 0.22 g/L rhamnolipid was initially added into the medium to facilitate the biodegradation of crude oil. In both situations, more than 58% of crude oil was degraded and further converted into accumulated cell biomass and rhamnolipids. These results suggest that Pseudomonas aeruginosa could degrade most of crude oil with direct or indirect addition of rhamnolipid. And this conclusion was further supported by another adsorption experiment, where the adsorption capacity of crude oil by killed cell biomass was negligible in comparison with the biologic activities of live cell biomass.
Biodegradation, Environmental ; Cell Culture Techniques ; methods ; Cell Proliferation ; drug effects ; Glycolipids ; pharmacology ; Petroleum ; metabolism ; microbiology ; Pseudomonas aeruginosa ; drug effects ; growth & development ; metabolism ; Water Pollutants, Chemical ; metabolism ; Water Purification ; methods