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Microbial Cell Factories Jul 2020Methylocella silvestris is a facultative aerobic methanotrophic bacterium which uses not only methane, but also other alkanes such as ethane and propane, as carbon and...
BACKGROUND
Methylocella silvestris is a facultative aerobic methanotrophic bacterium which uses not only methane, but also other alkanes such as ethane and propane, as carbon and energy sources. Its high metabolic versatility, together with the availability of tools for its genetic engineering, make it a very promising platform for metabolic engineering and industrial biotechnology using natural gas as substrate.
RESULTS
The first Genome Scale Metabolic Model for M. silvestris is presented. The model has been used to predict the ability of M. silvestris to grow on 12 different substrates, the growth phenotype of two deletion mutants (ΔICL and ΔMS), and biomass yield on methane and ethanol. The model, together with phenotypic characterization of the deletion mutants, revealed that M. silvestris uses the glyoxylate shuttle for the assimilation of C1 and C2 substrates, which is unique in contrast to published reports of other methanotrophs. Two alternative pathways for propane metabolism have been identified and validated experimentally using enzyme activity tests and constructing a deletion mutant (Δ1641), which enabled the identification of acetol as one of the intermediates of propane assimilation via 2-propanol. The model was also used to integrate proteomic data and to identify key enzymes responsible for the adaptation of M. silvestris to different substrates.
CONCLUSIONS
The model has been used to elucidate key metabolic features of M. silvestris, such as its use of the glyoxylate shuttle for the assimilation of one and two carbon compounds and the existence of two parallel metabolic pathways for propane assimilation. This model, together with the fact that tools for its genetic engineering already exist, paves the way for the use of M. silvestris as a platform for metabolic engineering and industrial exploitation of methanotrophs.
Topics: Beijerinckiaceae; Carbon; Ethanol; Genes, Bacterial; Genetic Engineering; Glyoxylates; Industrial Microbiology; Isocitrate Lyase; Malate Synthase; Metabolic Networks and Pathways; Methane; Models, Biological; Mutation; Propane; Proteomics
PubMed: 32677952
DOI: 10.1186/s12934-020-01395-0 -
Biotechnology For Biofuels 2016Propane, a major component of liquid petroleum gas (LPG) derived from fossil fuels, has widespread applications in vehicles, cooking, and ambient heating. Given the...
BACKGROUND
Propane, a major component of liquid petroleum gas (LPG) derived from fossil fuels, has widespread applications in vehicles, cooking, and ambient heating. Given the concerns about fossil fuel depletion and carbon emission, exploiting alternative and renewable source of propane have become attractive. In this study, we report the construction of a novel propane biosynthetic pathway in Escherichia coli.
RESULTS
We constructed an aldehyde reductases (ALR)-deprived E. coli strain BW25113(DE3) Δ13 via genetic engineering, which produced sufficient isobutyraldehyde precursors and finally achieved de novo synthesis of propane (91 μg/L) by assembling the engineered valine pathway and cyanobacterial aldehyde-deformylating oxygenase (ADO). Additionally, after extensive screening of ADO mutants generated by engineering the active center to accommodate branched-chain isobutyraldehyde, we identified two ADO mutants (I127G, I127G/A48G) which exhibited higher catalytic activity for isobutyraldehyde and improved propane productivity by three times (267 μg/L).
CONCLUSIONS
The propane biosynthetic pathway constructed here through the engineered valine pathway can produce abundant isobutyraldehyde for ADO and overcome the low availability of precursors in propane production. Furthermore, the rational design aiming at the ADO active center illustrates the plasticity and catalytic potential of ADO. These results together highlight the potential for developing a microbial biomanufacturing platform for propane.
PubMed: 27042209
DOI: 10.1186/s13068-016-0496-z -
Nature Communications Oct 2022Deoxygenation of aldehydes and their tautomers to alkenes and alkanes has implications in refining biomass-derived fuels for use as transportation fuel. Electrochemical...
Deoxygenation of aldehydes and their tautomers to alkenes and alkanes has implications in refining biomass-derived fuels for use as transportation fuel. Electrochemical deoxygenation in ambient, aqueous solution is also a potential green synthesis strategy for terminal olefins. In this manuscript, direct electrochemical conversion of vinyl alcohol and acetaldehyde on polycrystalline Cu to ethanol, ethylene and ethane; and propenol and propionaldehyde to propanol, propene and propane is reported. Sensitive detection was achieved using a rotating disk electrode coupled with gas chromatography-mass spectrometry. In-situ attenuated total reflection surface-enhanced infrared absorption spectroscopy, and in-situ Raman spectroscopy confirmed the adsorption of the vinyl alcohol. Calculations using canonical and grand-canonical density functional theory and experimental findings suggest that the rate-determining step for ethylene and ethane formation is an electron transfer step to the adsorbed vinyl alcohol. Finally, we extend our conclusions to the enol reaction from higher-order soluble aldehyde and ketone. The products observed from the reduction reaction also sheds insights into plausible reaction pathways of CO to C and C products.
PubMed: 36192409
DOI: 10.1038/s41467-022-33620-2 -
Journal of Bacteriology Dec 2003A new isolate, Gordonia sp. strain TY-5, is capable of growth on propane and n-alkanes with C(13) to C(22) carbon chains as the sole source of carbon. In whole-cell...
A new isolate, Gordonia sp. strain TY-5, is capable of growth on propane and n-alkanes with C(13) to C(22) carbon chains as the sole source of carbon. In whole-cell reactions, significant propane oxidation to 2-propanol was detected. A gene cluster designated prmABCD, which encodes the components of a putative dinuclear-iron-containing multicomponent monooxygenase, including the large and small subunits of the hydroxylase, an NADH-dependent acceptor oxidoreductase, and a coupling protein, was cloned and sequenced. A mutant with prmB disrupted (prmB::Kan(r)) lost the ability to grow on propane, and Northern blot analysis revealed that polycistronic transcription of the prm genes was induced during its growth on propane. These results indicate that the prmABCD gene products play an essential role in propane oxidation by the bacterium. Downstream of the prm genes, an open reading frame (adh1) encoding an NAD(+)-dependent secondary alcohol dehydrogenase was identified, and the protein was purified and characterized. The Northern blot analysis results and growth properties of a disrupted mutant (adh1::Kan(r)) indicate that Adh1 plays a major role in propane metabolism. Two additional NAD(+)-dependent secondary alcohol dehydrogenases (Adh2 and Adh3) were also found to be involved in 2-propanol oxidation. On the basis of these results, we conclude that Gordonia sp. strain TY-5 oxidizes propane by monooxygenase-mediated subterminal oxidation via 2-propanol.
Topics: Alcohol Dehydrogenase; Cloning, Molecular; Gene Expression Regulation, Bacterial; Gene Expression Regulation, Enzymologic; Gordonia Bacterium; Mixed Function Oxygenases; NAD; Propane; RNA, Messenger
PubMed: 14645271
DOI: 10.1128/JB.185.24.7120-7128.2003 -
Nutrients Mar 2023Increasing rates of cancer incidence and the side-effects of current chemotherapeutic treatments have led to the research on novel anticancer products based on dietary...
Increasing rates of cancer incidence and the side-effects of current chemotherapeutic treatments have led to the research on novel anticancer products based on dietary compounds. The use of metabolites and extracts has been proposed to reduce the proliferation of tumor cells by several mechanisms. In this study, we have shown the in vitro anti-proliferative and anti-inflammatory effect of two onion-derived metabolites propyl propane thiosulfinate (PTS) and propyl propane thiosulfonate (PTSO) on several human tumor lines (MCF-7, T-84, A-549, HT-29, Panc-1, Jurkat, PC-3, SW-837, and T1-73). We observed that this effect was related to their ability to induce apoptosis regulated by oxidative stress. In addition, both compounds were also able to reduce the levels of some pro-inflammatory cytokines, such as IL-8, IL-6, and IL-17. Therefore, PTS and PTSO may have a promising role in cancer prevention and/or treatment.
Topics: Humans; Allium; Propane; Diet; Onions; Anti-Inflammatory Agents
PubMed: 36986093
DOI: 10.3390/nu15061363 -
Water Research May 2023Nitrate contamination has been commonly detected in water environments and poses serious hazards to human health. Previously methane was proposed as a promising electron...
Nitrate contamination has been commonly detected in water environments and poses serious hazards to human health. Previously methane was proposed as a promising electron donor to remove nitrate from contaminated water. Compared with pure methane, natural gas, which not only contains methane but also other short chain gaseous alkanes (SCGAs), is less expensive and more widely available, representing a more attractive electron source for removing oxidized contaminants. However, it remains unknown if these SCGAs can be utilized as electron donors for nitrate reduction. Here, two lab-scale membrane biofilm reactors (MBfRs) separately supplied with propane and butane were operated under oxygen-limiting conditions to test its feasibility of microbial nitrate reduction. Long-term performance suggested nitrate could be continuously removed at a rate of ∼40-50 mg N/L/d using propane/butane as electron donors. In the absence of propane/butane, nitrate removal rates significantly decreased both in the long-term operation (∼2-10 and ∼4-9 mg N/L/d for propane- and butane-based MBfRs, respectively) and batch tests, indicating nitrate bio-reduction was driven by propane/butane. The consumption rates of nitrate and propane/butane dramatically decreased under anaerobic conditions, but recovered after resupplying limited oxygen, suggesting oxygen was an essential triggering factor for propane/butane-based nitrate reduction. High-throughput sequencing targeting 16S rRNA, bmoX and narG genes indicated Mycobacterium/Rhodococcus/Thauera were the potential microorganisms oxidizing propane/butane, while various denitrifiers (e.g. Dechloromonas, Denitratisoma, Zoogloea, Acidovorax, Variovorax, Pseudogulbenkiania and Rhodanobacter) might perform nitrate reduction in the biofilms. Our findings provide evidence to link SCGA oxidation with nitrate reduction under oxygen-limiting conditions and may ultimately facilitate the design of cost-effective techniques for ex-situ groundwater remediation using natural gas.
Topics: Humans; Propane; Nitrates; Natural Gas; RNA, Ribosomal, 16S; Alkanes; Methane; Butanes; Oxidation-Reduction; Biofilms; Oxygen; Water; Bioreactors
PubMed: 36947926
DOI: 10.1016/j.watres.2023.119887 -
Biophysical Journal Mar 2023The cationic lipid 1,2-dioleoyl-3-trimethylammonium propane (DOTAP) is one of the original synthetic cationic lipids used for the liposomal transfection of...
The cationic lipid 1,2-dioleoyl-3-trimethylammonium propane (DOTAP) is one of the original synthetic cationic lipids used for the liposomal transfection of oligonucleotides in gene therapy. The key structural element of DOTAP is its quaternary ammonium headgroup that is responsible for interactions with both nucleic acids and target cell membranes. Because these interactions are fundamental to the design of a major class of transfection lipids, it is important to understand the structure of DOTAP and how it interacts with halide counterions. Here, we use x-ray and neutron diffraction techniques to examine the structure of DOTAP and how chloride (Cl-) and iodide (I-) counterions alter the hydration properties of the DOTAP headgroup. A problem of particular interest is the poor solubility of DOTAP/I- in water solutions. Our results show that the poor solubility results from very tight binding of the I- counterion to the headgroup and the consequent expulsion of water. The structural principles we report here are important for assessing the suitability of DOTAP and its quaternary ammonium derivatives for transfection.
Topics: Propane; Liposomes; Quaternary Ammonium Compounds; Fatty Acids, Monounsaturated; Water; Cations
PubMed: 36703558
DOI: 10.1016/j.bpj.2023.01.031 -
Microbiome Jun 2018Natural gas contains methane and the gaseous alkanes ethane, propane and butane, which collectively influence atmospheric chemistry and cause global warming....
BACKGROUND
Natural gas contains methane and the gaseous alkanes ethane, propane and butane, which collectively influence atmospheric chemistry and cause global warming. Methane-oxidising bacteria, methanotrophs, are crucial in mitigating emissions of methane as they oxidise most of the methane produced in soils and the subsurface before it reaches the atmosphere. Methanotrophs are usually obligate, i.e. grow only on methane and not on longer chain alkanes. Bacteria that grow on the other gaseous alkanes in natural gas such as propane have also been characterised, but they do not grow on methane. Recently, it was shown that the facultative methanotroph Methylocella silvestris grew on ethane and propane, other components of natural gas, in addition to methane. Therefore, we hypothesised that Methylocella may be prevalent at natural gas seeps and might play a major role in consuming all components of this potent greenhouse gas mixture before it is released to the atmosphere.
RESULTS
Environments known to be exposed to biogenic methane emissions or thermogenic natural gas seeps were surveyed for methanotrophs. 16S rRNA gene amplicon sequencing revealed that Methylocella were the most abundant methanotrophs in natural gas seep environments. New Methylocella-specific molecular tools targeting mmoX (encoding the soluble methane monooxygenase) by PCR and Illumina amplicon sequencing were designed and used to investigate various sites. Functional gene-based assays confirmed that Methylocella were present in all of the natural gas seep sites tested here. This might be due to its ability to use methane and other short chain alkane components of natural gas. We also observed the abundance of Methylocella in other environments exposed to biogenic methane, suggesting that Methylocella has been overlooked in the past as previous ecological studies of methanotrophs often used pmoA (encoding the alpha subunit of particulate methane monooxygenase) as a marker gene.
CONCLUSION
New biomolecular tools designed in this study have expanded our ability to detect, and our knowledge of the environmental distribution of Methylocella, a unique facultative methanotroph. This study has revealed that Methylocella are particularly abundant at natural gas seeps and may play a significant role in biogeochemical cycling of gaseous hydrocarbons.
Topics: Base Sequence; Beijerinckiaceae; Methane; Natural Gas; Oxygenases; Phylogeny; Propane; RNA, Ribosomal, 16S; Sequence Analysis, DNA; Soil Microbiology
PubMed: 29954460
DOI: 10.1186/s40168-018-0500-x -
Molecules (Basel, Switzerland) Oct 2022The use of phytogenic extracts is considered a sustainable strategy for the prevention of fish diseases, including as a potential option due to their variety of...
Antibacterial and Antiparasitic Activity of Propyl-Propane-Thiosulfinate (PTS) and Propyl-Propane-Thiosulfonate (PTSO) from against Gilthead Sea Bream Pathogens in In Vitro and In Vivo Studies.
The use of phytogenic extracts is considered a sustainable strategy for the prevention of fish diseases, including as a potential option due to their variety of bioactive compounds. In this study, we analyzed the antibacterial and antiparasitic potential of propyl-propane-thiosulfinate (PTS) and propyl-propane-thiosulfonate (PTSO) from onions. The in vitro activity against , , and of both compounds was tested. In addition, the viability of larvae was evaluated. Moreover, a diet that consisted of a blend of PTS/PTSO (ALLIUM) was used. A total of 90 gilthead sea bream juveniles were tested against subsp. after 12 weeks of dietary administration. Furthermore, 150 fish with a rate of 10-15 parasites/fish were fed for 21 days and the number of gill parasites was recorded. All strains were sensitive to both compounds. PTSO showed the highest inhibitory effect against all target strains, while PTS showed higher effectiveness against Fish from ALLIUM group presented the highest probability of survival, increasing up to 91.1%, whereas in the control group, the probability of survival was 66.7%. The number of parasites in the gilthead sea bream decreased in the ALLIUM group over time. These results suggest the inclusion of PTS and PTSO in feed as a natural strategy to prevent antibacterial and antiparasitic fish diseases.
Topics: Animals; Sea Bream; Onions; Propane; Antiparasitic Agents; Anti-Bacterial Agents; Allium; Fish Diseases; Plant Extracts
PubMed: 36296491
DOI: 10.3390/molecules27206900 -
PeerJ 2022Indirect calorimetry (IC) systems measure the fractions of expired carbon dioxide (FCO), and oxygen (FO) recorded at the mouth to estimate whole-body energy production....
OBJECTIVE
Indirect calorimetry (IC) systems measure the fractions of expired carbon dioxide (FCO), and oxygen (FO) recorded at the mouth to estimate whole-body energy production. The fundamental principle of IC relates to the catabolism of high-energy substrates such as carbohydrates and lipids to meet the body's energy needs through the oxidative process, which are reflected in the measured oxygen uptake rates (V̇O) and carbon dioxide production rates (V̇CO). Accordingly, it is important to know the accuracy and validity of V̇Oand V̇CO measurements when estimating energy production and substrate partitioning for research and clinical purposes. Although several techniques are readily available to assess the accuracy of IC systems at a single point for V̇CO and V̇O, the validity of such procedures is limited when used in testing protocols that incorporate a wide range of energy production (, basal metabolic rate and maximal exercise testing). Accordingly, we built an apparatus that allowed us to manipulate propane burn rates in such a way as to assess the linearity of IC systems. This technical report aimed to assess the accuracy and linearity of three IC systems using our in-house built validation procedure.
APPROACH
A series of trials at different propane burn rates (PBR) (, 200, 300, 400, 500, and 600 mL min) were run on three IC systems: Sable, Moxus, and Oxycon Pro. The experimental values for V̇O and V̇CO measured on the three IC systems were compared to theoretical stoichiometry values.
RESULTS
A linear relationship was observed between increasing PBR and measured values for V̇Oand V̇CO (99.6%, 99.2%, 94.8% for the Sable, Moxus, and Jaeger IC systems, respectively). In terms of system error, the Jaeger system had significantly ( < 0.001) greater V̇O(mean difference ( = -0.057, standard error ( = 0.004), and V̇CO( = -0.048, = 0.002) error compared to either the Sable (V̇O, = 0.044, = 0.004; V̇CO, = 0.024, = 0.002) or the Moxus (V̇O2, = 0.046, = 0.004; V̇CO, = 0.025, = 0.002) IC systems. There were no significant differences between the Sable or Moxus IC systems.
CONCLUSION
The multiple PBR approach permitted the assessment of linearity of IC systems in addition to determining the accuracy of fractions of expired gases.
Topics: Propane; Calorimetry, Indirect; Carbon Dioxide; Oxygen Consumption; Oxygen
PubMed: 36061755
DOI: 10.7717/peerj.13882