Methane Research Articles

Germanium doped D-shaped PCF-SPR methane high sensitivity sensor

Abstract A D-shaped photonic crystal fiber doped with germanium dioxide methane gas sensor based on SPR effect is proposed. The substrate of the fiber is silicon dioxide doped with germanium dioxide, and the polished surface is used as a substrate for gold-plated and methane-sensitive membranes where the sensing area is in direct contact with methane gas. Effects of different germanium dioxide doping concentrations and the structural parameters of the photonic crystal fiber on the performance of the sensor are numerically investigated by the finite element method. Simulation results show that when the germanium dioxide doping concentration is 4.1%, the maximum sensitivity of sensor is 82 nm/% with a maximum resolution of 1.2195 × 10–4 in the range of 0 ∼ 3.5% methane concentration. The proposed sensor not only has a simple structure, but also exhibits high sensitivity, thus the sensor has great potential in pre-warning and remote monitoring of methane gas leakage.

Characteristics and Origin of Natural Gas in Yongfeng Sub-Sag of Bogda Mountain Front Belt

By systematically analyzing the natural gas composition, carbon isotopes, and source rock characteristics in the Yongfeng sub-sag of the Bogda Mountain front belt, natural gas characteristics were determined, and the genetic types and sources of natural gas were investigated. The research results indicate that methane is the main component of natural gas in the Yongfeng sub-sag, with low levels of heavy hydrocarbons and a high drying coefficient. These characteristics make it dry gas, which refers to natural gas with a methane content of over 95%. The ethane carbon isotope δ13C2 of natural gas is −28.5‰ and belongs to oil type gas. The methane carbon isotope δ13C1 of natural gas is −58.6‰~−59.4‰, has a relatively depleted methane carbon isotope value, shows significant differences from the surrounding natural gas methane carbon isotope, and belongs to the category of biogenic gas. The Permian Lucaogou Formation is the main source rock in the study area, with good organic matter abundance. The microscopic components of kerogen are mainly composed of sapropelic formations and the organic matter type is I–II1. The source rock has a high maturity and has reached the mature stage, mainly consisting of oil and wet gas. The ethane carbon isotope of natural gas in the Yongfeng sub-sag shows as oil type gas, which is consistent with the kerogen type of the Lucaogou Formation source rocks, indicating that the natural gas mainly comes from the Lucaogou Formation source rocks. Based on comprehensive data and information on natural gas composition, carbon isotopes, and burial history of the source rocks, it is believed that some of the crude oil generated from the Lucaogou Formation in the early stage underwent biodegradation due to tectonic uplift, resulting in biogenic methane and the formation of crude oil biodegraded gas.

Hybrid bottom-up and top-down framework resolves discrepancies in Canada’s oil and gas methane inventories

Estimating accurate oil and gas methane emissions has been a global challenge, highlighted by a twofold discrepancy between atmospheric measurement-based estimates and emission inventories. The principle of continuous improvement in Canada’s National Inventory Report has led to an unstable baseline in recent years for tracking emission reduction progress. The gaps between previous inventory estimates and inversions exceeded 60%. Here we show that incorporating new source-resolved information derived from low-altitude aerial survey data has narrowed this gap by 80%, reducing the discrepancy to 10% for the 2010–2014 baseline. This study proposes a hybrid emission reporting framework, complemented by an ensemble inversion top-down method using continuous tower-based atmospheric measurements, to establish a stable baseline and provide independent verification. As the 2030 target year for emission reduction approaches, we report a significant 27% decline (19%–34%) in inverse oil and gas methane emissions from 2010 to 2022 in Alberta and Saskatchewan, Canada, and a 41% decline (26%–56%) as calculated using the 2024 official inventory.

High-Q fano resonance metasurface sensor for refractive index and methane gas concentration measurement

High-quality-factor Fano resonances excited by metasurfaces have been playing an important role in the field of optical sensing. A high-performance sensor for refractive index and methane concentration measurement is designed and prepared in this paper. The symmetry of the structure is broken by altering the size of the rectangular holes in the tetramer, resulting fano resonance Q-factor of 34176 and modulation depth of 100%. The finite-difference time-domain (FDTD) method is used to simulate the structure. The results show that the refractive index and methane concentration sensitivity are 325 nm/RIU and −1.44 nm/%, respectively. The FOM can achieve 10156 RIU−1. Furthermore, experiments are carried out on the gas application of the structure and the sensitivity of methane concentration is −1.03 nm/%. Therefore, the proposed metasurface has more practical and feasible significance in background refractive index and gas environment monitoring.

The effect of Vachellia eriolaba leaf meal inclusion on growth performance, blood parameters and methane gas emission in lambs fed diets containing ammoniated maize stover

The study evaluated the effect of Vachellia erioloba leaf meal in diets containing ammoniated maize stove on growth performance, methane emission and heath of growing lambs. Thirty-two female lambs were allocated to the following four dietary treatments: total mixed ration (TMR, control), 20% inclusion of untreated maize stover (UMS), 20% inclusion of ammoniated maize stover (AMS), and combined inclusion of 10% ammoniated maize stover and 10% Vachellia erioloba leaves (AMSVL). Each treatment was replicated 8 times and a lamb in an individual pen was regarded as an experimental unit in a completely randomized design. Feed intake was higher (P < 0.05) in lambs fed the AMS and AMSVL diets compared to those fed UMS. Final body weights were higher in lambs fed the AMS and AMSVL diets. Both average daily gain (ADG) and feed convention ratio (FCR) were not affected by diet. In comparison with the AMS and AMSVL diets, the lambs fed the UMS diet had the highest (P < 0.05) methane emission. Overall, lambs fed the control diets had the lowest (P < 0.05) methane gas emission. Blood hematological values were affected by diet with the AMSVL fed lambs having the highest (P < 0.05) mean platelet volume (MPV) and procalcitonin (PCT) values. Furthermore, total albumin, amylase and total bilirubin were the highest (P < 0.05) in lambs fed on the AMSVL diet. Lambs fed on AMS diet had the highest (P < 0.05) serum urea levels. It can be concluded that combined inclusion of ammoniated maize stover and Vachellia leaves improved feed value and lamb performance when compared to the individual inclusion of both UMS and AMS.

Capturing a methanogenic carbon monoxide dehydrogenase/acetyl-CoA synthase complex via cryogenic electron microscopy

Approximately two-thirds of the estimated one-billion metric tons of methane produced annually by methanogens is derived from the cleavage of acetate. Acetate is broken down by a Ni-Fe-S-containing A-cluster within the enzyme acetyl-CoA synthase (ACS) to carbon monoxide (CO) and a methyl group (CH3+). The methyl group ultimately forms the greenhouse gas methane, whereas CO is converted to the greenhouse gas carbon dioxide (CO2) by a Ni-Fe-S-containing C-cluster within the enzyme carbon monoxide dehydrogenase (CODH). Although structures have been solved of CODH/ACS from acetogens, which use these enzymes to make acetate from CO2, no structure of a CODH/ACS from a methanogen has been reported. In this work, we use cryo-electron microscopy to reveal the structure of a methanogenic CODH and CODH/ACS from Methanosarcina thermophila (MetCODH/ACS). We find that the N-terminal domain of acetogenic ACS, which is missing in all methanogens, is replaced by a domain of CODH. This CODH domain provides a channel for CO to travel between the two catalytic Ni-Fe-S clusters. It generates the binding surface for ACS and creates a remarkably similar CO alcove above the A-cluster using residues from CODH rather than ACS. Comparison of our MetCODH/ACS structure with our MetCODH structure reveals a molecular mechanism to restrict gas flow from the CO channel when ACS departs, preventing CO escape into the cell. Overall, these long-awaited structures of a methanogenic CODH/ACS reveal striking functional similarities to their acetogenic counterparts despite a substantial difference in domain organization.

Application of omega 3,6 with Moringa oleifera suplemented vitamin E on rumen fluid characteristics, microbial protein synthesis, and methane gas production in goats on suboptimal lands

Changes in feeding patterns were needed to overcome the problem of methane gas emissions from ruminant livestock and the problem of low productivity at the smallholder livestock level. This solution involves direct action against the gas produced in the stomach of ruminants by providing feed containing active substances to reduce the microbes that produce gas in the stomach. One alternative feed that was often used as a promoter of improving rumen fluid characteristics was the use of omega 3.6 sources together with Moringa leaves enriched with vitamin E. This research aimed to investigate the effect of feeding on methane gas production in goats. The research method used a Randomized Block Design (RAK) with four treatments and five replications in vitro. From the research results, it could be concluded that the use of omega 3.6 together with Moringa leaves enriched with vitamin E was able to reduce methane gas production by 25.62% with a Volatile Fatty Acid (VFA) value of 144.53 mM, pH around 6.99, NH3 11.87 mg/100ml, microbial biomass 20.42 mg/ml, microbial protein 217.58mg/ml, bacterial colony 5.34x109 cells/ml and protozoa population 29x106 cells/ml. This conclusion shows that the use of omega 3.6 with Moringa oleifera supplemented with vitamin E has the potential to consistently improve rumen fluid characteristics and reduce methane gas emissions by using a combination of omega 3.6 sources and Moringa leaves in suboptimal land, as well as vitamin E supplementation.

Methane hydrate formation between graphene oxide nanosheets: Insights from molecular dynamics simulations

This work focuses computationally on the role of graphene and graphene oxide nanosheets in improving the formation of methane gas hydrate and their potential as a promising alternative to traditional gas storage and transportation method. To evaluate methane gas mechanism storage between graphene and graphene oxide nanosheets including C8O-flat, C8O-polar, and C8(OH)2 surfaces, radial distribution function, mean squared displacement, number of hydrogen bonding, and coordination number were taken under consideration. Our results showed that methane hydrate is well formed between graphene, C8O-flat, and C8O-polar nanosheets. C8(OH)2 nanosheet has an inhibitory effect on the gas hydrate formation caused by the formation of hydrogen bonds between the hydroxyl functional groups of the sheets and water molecules. To further investigate the degree of hydrate formation, a four-body structural order (F4φ) was obtained. The values of the F4φ parameter for the C8O-flat, graphene, C8O-polar, and C8(OH)2 systems are 0.6, 0.55, 0.51, and −0.02, respectively. These values indicate the presence of an almost complete and regular network of methane hydrate between the first three mentioned sheets. However, the negative value of the F4φ parameter in the last one suggests the absence of significant hydrate formation by ice-like structure of water molecules. The effect of different temperatures on the formation of methane hydrate was also investigated. It is observed that the hydrate structure completely breaks down in the range of 300–400 K in the different structures.

Plasma assisted single-step synthesis of carbon-coated SrFe2O4 electrodes for enhancing supercapacitor and oxygen evolution reaction

Developing highly efficient, conductive, and porous electrode materials for superior electrochemical bifunctional applications presents a formidable challenge, particularly when considering impurity-free large-scale production. This investigation focuses on synthesizing a composite material of highly conductive amorphous carbon-coated SrFe2O4 nanoparticles to enhance supercapacitor and oxygen evolution performance. The C@SrFe2O4 nanoparticles were synthesized through a thermal plasma process utilizing argon, methane, and carbon dioxide gas environments. The prepared samples' phase, crystal structure, morphology, elemental composition, and chemical state analysis were thoroughly examined. The electrochemical performance of the prepared samples, including Fe3O4, SrO, and C@SrFe2O4 electrodes, was evaluated for their suitability in electrochemical capacitor applications. Remarkably, C@SrFe2O4 nanoparticles exhibited notable electrochemical pseudocapacitive behavior, demonstrating a significantly higher specific capacitance of 588.7 F/g at a current density of 1 A/g. Moreover, at a current density of 10 A/g, the C@SrFe2O4 electrode exhibited outstanding cycling stability, maintaining 91 % of its initial capacitance over 5000 charge-discharge cycles. Furthermore, it showcased exceptional and uniform electrocatalytic activity for the OER, requiring only 186 mV in overpotentials to achieve a current density of 10 mA/ cm2. These findings underscore the potential of mesoporous C@SrFe2O4 nanoparticles as promising materials for supercapacitors and OER applications.

Preparation and growth mechanism of high-quality multilayer graphene from simulated coal pyrolysis gas via chemical vapor deposition

Chemical vapor deposition (CVD) of graphene from coal pyrolysis gas provides new ways for both large-scale graphene preparation and high value-added utilization of coal. However, green, efficient and continuous preparation of high-quality multilayer graphene with both good uniformity and ideal structure characteristic remains a great challenge. Herein, we first investigated the influence of main carbonaceous species (CH4, C2H6, C3H8, CO2, and CO) in coal pyrolysis gas on the quality of CVD graphene products. The experimental results indicated that CO2 and CO have little effect on the growth of graphene, while methane as carbon source is conducive to obtain ideal graphene materials, propane and ethane could also influence structural defects and layer number of graphene products remarkably. On this basis, we designed a mixed gas of methane, ethane, and propane with optimized ratio as simulated coal pyrolysis gas, and successfully prepared high-quality multilayer graphene products on nickel foam from the as-designed simulated coal pyrolysis gas by CVD method. Notably, with a CH4:C2H6:C3H8 ratio of 2:1:1, the graphene products prepared from simulated coal pyrolysis gas outperformed that of raw coal pyrolysis gas in terms of physical structure, layer number, and quality uniformity. The corresponding I2D/IG value reached 0.97. The graphene growth process and mechanism were investigated and discussed macroscopically and microscopically. This work is of great significance for the intrinsic understanding of CVD growth of graphene from coal pyrolysis gas, and also inspires an efficient and environmentally friendly avenue for high-throughput, uniform production of high-quality graphene materials.

Rancang Bangun Alat Otomatisasi Pengomposan dari Sampah Organik Berbasis Internet of Things

Organic waste management in Indonesia is currently suboptimal. Approximately 33.7% of waste is not properly managed, and 56% of the total waste consists of organic waste, most of which comes from households. Composting is an effective method for managing organic waste. However, many people are still reluctant to convert organic waste into compost due to the lengthy process, which typically takes 2 to 3 months. This study proposes an IoT-based composting automation system with the goal of accelerating the composting process without the use of additional microorganisms, producing both dry and liquid compost. The system method involves integrating Internet of Things (IoT) technology with sensors: DHT22 for temperature monitoring, soil moisture sensors for measuring soil moisture, MQ-4 sensors for detecting methane gas, pH sensors for measuring soil acidity, and water level sensors for detecting the height of liquid compost. Data collected from these sensors is used to automatically control the organic waste mixing process until all composting specifications are met. The results indicate that this system effectively accelerates the composting process to 24 days for dry compost and 19 days for liquid compost without the need for additional microorganisms, while producing compost of high quality according to the SNI-19-7030-2004 specifications.

Nutritional Value, Phytochemical Properties of Different Parts of Dill (Anethum graveolens L.) and Their Effects on in vitro Digestibility in Ruminants

Introduction: At the interface between man, animal and environment, the use of phytobiotics in agroecology practices has been developed as one of the most effective nutritional strategies for animal performance, health, and well-being. This study aimed to determine the effect of extracts from different parts (leaves, flowers and fruits) of a medicinal and food plant, dill ( Anethum graveolens L.) on in vitro digestibility in small ruminants. Methods: Chemical and parietal composition and antioxidant activity were determined, and nutritional and energy values were predicted. Substrate fermentation was studied using in vitro gas production techniques in sheep and goat intestines. Results: Flowers were rich in secondary metabolites, while fruits were rich in fiber and showed the best antioxidant activity against DPPH (IC50 = 41.71 μg/ml). The studied dill plant parts were digestible and nutritious, mainly fruits, with lower gas production rates compared to leaves and flowers in sheep and goats. The methane gas produced by fermentation was not significant in the leaves of either species. Conclusion: In summary, A. graveolens fruits can be considered a natural source of antioxidants that improve animal nutrition and health. Moreover, A. graveolens leaves can play an ecological role in the environment.

A Detailed Study of Jupiter’s Great Red Spot over a 90-day Oscillation Cycle

Jupiter’s Great Red Spot (GRS) is known to exhibit oscillations in its westward drift with a 90-day period. The GRS was observed with the Hubble Space Telescope on eight dates over a single oscillation cycle in 2023 December to 2024 March to search for correlations in its physical characteristics over that time. Measured longitudinal positions are consistent with a 90-day oscillation in drift, but no corresponding oscillation is found in latitude. We find that the GRS size and shape also oscillate with a 90-day period, having a larger width and aspect ratio when it is at its slowest absolute drift (minimum date-to-date longitude change). The GRS’s UV and methane gas absorption-band brightness variations over this cycle were small, but the core exhibited a small increase in UV brightness in phase with the width oscillation; it is brightest when the GRS is largest. The high-velocity red collar also exhibited color changes, but out of phase with the other oscillations. Maximum interior velocities over the cycle were about 20 m s−1 larger than minimum velocities, slightly larger than the mean uncertainty of 13 m s−1, but velocity variability did not follow a simple sinusoidal pattern as did other parameters such as longitude width or drift. Relative vorticity values were compared with aspect ratios and show that the GRS does not currently follow the Kida relation.

Anaerobic Oxidation of Oil by Microbial Communities of Bottom Sediments of a Natural Oil Seepage Site (Bolshaya Zelenovskaya, Middle Baikal)

The microbial communities of bottom sediments of the Bolshaya Zelenovskaya oil seepage site (Lake Baikal) were investigated to assess their diversity and potential functional activity in the anaerobic degradation of oil. Microorganisms of the subsurface and deep sediment layers were grown in enrichment cultures supplemented with oil and various electron acceptors for 1 year at 10°C, and it was found that the concentrations of n-alkanes and polyaromatic hydrocarbons decreased by 1.2–2 and 2.2–2.8 times, respectively. Hydrocarbon conversion was accompanied by generation of hydrocarbon gases (methane and ethane). The microbial community of subsurface sediments had a higher bacterial diversity than the community of deep horizons and was composed of microorganisms specialized in degradation of a broad range of substrates, including oil hydrocarbons. The community of the deep sediment layer was dominated by Atribacterota, Caldisericota, and Bathyarchaeia (Thermoproteota), as well as members of the “rare biosphere”: Elusimicrobiota and Candidatus Hadarchaeota. Apparently, oil degradation in the bottom sediments of Lake Baikal is primarily mediated by members of the phyla Bacillota, Pseudomonadota, Chloroflexota, Actinomycetota, Desulfobacterota, Atribacterota, Halobacteriota, and Bathyarchaeia (Thermoproteota).

Nano-encapsulation of essential amino acids: ruminal methane, carbon monoxide, hydrogen sulfide and fermentation

This study aimed to evaluate the effect of nano-encapsulation of four essential amino acids (AA), threonine, methionine, tryptophan, and lysine on in vitro ruminal total gas, methane, carbon monoxide, and hydrogen sulfide production as well as the rumen fermentation profile in cattle. The highest (P < 0.001) rate and asymptotic gas production after 48 h of incubation was observed in the diets that had threonine, followed by lysine, methionine, and tryptophan. Asymptotic methane gas production decreased in the following order: threonine > lysine > tryptophan > methionine (P < 0.0001) and the rate of production per hour followed the same trend (P = 0.0259). CH4 parameters showed that in 4 h, 24 h, and 48 h of incubation the lowest methane production was obtained in the diet with methionine (P < 0.05) and the highest one in diet supplemented with threonine. Methane fractions showed that methionine-containing diets resulted in more (P < 0.05) metabolizable energy versus methane, followed by tryptophan-containing, and then lysine-containing diets. Methionine-fortified diets seem to be the most eco-friendly among those studied regarding methane output. However, based on methane, CO, and H2S output as well as the rumen fermentation profile nano-encapsulated lysine is recommended for use in ruminant nutrition.

The Combined Effect of Four Nutraceutical-Based Feed Additives on the Rumen Microbiome, Methane Gas Emission, Volatile Fatty Acids, and Dry Matter Disappearance Using an In Vitro Batch Culture Technique

This study aimed to investigate the effect of an essential oil/fumaric combination, mannan-oligosaccharide, galactooligosaccharide, and a mannan-oligosaccharide/galactooligosaccharide combination on the dry matter disappearance (DMD), gas production, greenhouse gasses, volatile fatty acid, and microbial community of a total mixed ration using a 24 h in vitro batch culture technique. The study design was a completely randomized design with four treatments as follows: a control treatment without any additives, the control treatment supplemented with galactooligosaccharide at 3% (Gos treatment), a galactooligosaccharide and mannan-oligosaccharide mixture at 1:1 at 3% (Gosmos treatment), or an essential oil blend (200 μL/g feed) and fumaric acid at 3% combination (Eofumaric treatment). The Gosmos treatment had the highest (p &lt; 0.05) DMD (63.8%) and the numerical lowest acetate–propionate ratio (p = 0.207), which was 36.9% higher compared to the control. The lowest Shannon index, Simpson’s index, and all the diversity indices were recorded for the Eofumaric treatment, while the other treatments had similar Shannon index, Simpson’s index, and diversity index. The Z-score differential abundance between the Eofumaric and the control indicated that the inclusion of the Eofumaric treatment differentially increased the abundance of Patescibacteria, Synergistota, Chloroflexi, Actinobacteriota, Firmicutes, and Euryarchaeota while Verrucomicrobiota, WPS-2, Fibrobacterota, and Spirochaetota were decreased. The Random Forest Classification showed that the lower relative abundance of Fibrobacterota, Spirochaetota, and Elusimicrobiota and the higher relative abundance of Firmicutes and Chloroflexi were most impactful in explaining the microbial community data. Overall, the essential oil blend showed great potential as a methane gas mitigation strategy by modifying rumen fermentation through changes in the microbial community dynamics.

Kinetics of methane hydrate formation in a 1200 ml unstirred reactor for natural gas storage

Solidified natural gas (SNG) technology via clathrate hydrates, enhanced by promoters such as tetrahydrofuran (THF), promises large-scale natural gas storage due to its high volumetric capacity and mild storage conditions. Despite its potential for industrial scale-up, limited research exists on methane hydrate formation behaviors in large reactors (>1000 cm3), which is crucial for evaluating practical storage performance. In this study, methane hydrate formation kinetics were investigated in a scaled-up unstirred reactor (1200 cm3) at 288.15 K and 283.15 K, and 5.0 MPa. Methane uptake, system pressure, gas and liquid phase temperatures, and hydrate morphologies were analyzed to describe the dynamic hydrate formation process. Results reveal three effects of increased reactor size in contrast to smaller reactors: (i) heterogeneous distribution of THF-rich and methane-rich hydrates; (ii) hydrate bulk show a hollow inner structure with a cavity due to the wall-climbing behavior of hydrate growth; (iii) optimal THF concentration no longer always agrees with stoichiometric 5.56 mol%, which is case-dependent. These effects are attributed to higher diffusion resistances for methane molecules and more intensive heat accumulation. These findings provide some insight into the kinetics of methane hydrate formation in industrial reactors, which is critical for the commercialization of SNG technology.

Effects of Hydrogen on Ammonia/Methane/Air Combustion in a Can-type Combustor

In recent years, the importance of blending traditional methane gas with alternative fuels in combustion to reduce emissions has gained increasing recognition. Existing literature has demonstrated the successful operation of ammonia and hydrogen as fuels in diesel engines. However, there is still insufficient information regarding the combustion of methane in combination with ammonia and hydrogen. This paper investigates the effects of replacing ammonia with hydrogen in blends consisting of 70% CH4 and 30% NH3, with hydrogen substitution levels of 0%, 10%, 30%, 50%, 70%, and 90%. The simulation was carried out using the SST k-ω turbulence model and steady diffusion flamelet model. Calculations using Okafor-mech to predict the emission characteristics were also attempted to determine concentration values more accurately. Results show that as the proportion of hydrogen in the blended fuel increases, the maximum temperature rises by 29.28 K. There is an increase in emissions of carbon dioxide and carbon monoxide, while nitrogen oxide emissions decrease.

Upcycling food waste as a low-cost cultivation medium for Chlorella sp. microalgae.

Global food loss and waste have raised environmental concerns regarding the generation of greenhouse gases (e.g., carbon dioxide and methane gas), which directly contribute to climate change. To address these concerns, the present research aims to upcycle food waste into an alternative culture medium for the cultivation of microalgae. Various parameters including pretreatment of food waste (i.e., autoclave and non-autoclave), concentration of food waste culture medium (i.e., 10%, 30%, 50%, 70%, 90% and 100%), harvesting efficiency and biochemical compounds of Chlorella sp. microalgae were carried out. Based on the preliminary findings, the highest biomass concentration obtained from 10% food waste culture medium in the autoclave for Chlorella sp., including strains FSP-E, ESP-31 and CY-1, were 2.869 ± 0.022, 2.385 ± 0.018 and 0.985 ± 0.0026 g L-1, respectively. Since Chlorella vulgaris FSP-E exhibited the highest biomass concentration, this microalgal strain was selected to examine the subsequent parameters. Cultivation of C. vulgaris FSP-E in 100FW achieves a biomass concentration of 4.465 ± 0.008 g L-1 with biochemical compounds of 6.94 ± 1.396, 248.24 ± 0.976 and 406.23 ± 0.593 mg g-1 for lipids, carbohydrates and proteins, respectively. This study shows that using food waste as an alternative culture medium for C. vulgaris FSP-E can achieve substantial biomass productivity and biochemical content. This research work would contribute to the concept of net zero emission and transitioning toward a circular bioeconomy by upcycling food waste as an alternative culture medium for the cultivation of microalgae. © 2024 Society of Chemical Industry.

Substantiating of oil and gas prospects of Mesozoic sediments based on the geochemical model of mud volcanoes in the Shamakhi-Gobustan structural element of the South Caspian megadepression

There are up to 120 mud volcanoes in the Shamakhi-Gobustan region. During the process of mud volcano eruptions, a large amount of solid, liquid, and gaseous products are thrown to the Earth’s surface, which are widely used for the identification of oil and gas deposits and are considered the main indicator of the productivity of the basin. According to laboratory results from the analysis of solid, liquid, and gas products of mud volcanoes, it is possible to obtain detailed information about the oil-gas content of deep-lying sediments. Therefore, the study of the geochemical composition of the mud volcanoes in the Shamakhi-Gobustan trough plays a major role in the discovery of new oil-gas and gas-condensate deposits. To clarify the changes in the chemical and isotopic composition of gases from mud volcanoes in the Shamakhi-Gobustan trough and to evaluate the oil-bearing and gas-bearing potential of Mesozoic sediments, the characteristics of changes in the isotopic composition of methane gas, heavy hydrocarbons, carbon dioxide, ni- trogen, as well as CH4 and CO2, were studied. The amount of methane in the gas emissions released from mud volcanoes in the Azerbaijan region is more than 90%. The amount of CH4 in the mud volcanoes of the Shamakhi-Gobustan trough ranges from 78.5% to 97.56%. The minimum amount of methane is found in North Gobustan (Gizmeydan 86.8%, Malikchobanli 78.5%), while relatively high amounts are mainly noted in Central (Kushchu 97.55%) and South Gobustan (including Dashgil 97.57%, Goturdag 96.55%, Bahar 96.78%). Mud vol- canoes are less developed in the North Gobustan region and are small in size. In the Central zone, both the size and the number of volcanic cones increase significantly compared to North Gobustan. The largest and most active volcanoes have developed in the southern zone of the trough. Huge mud volcanoes such as Dashmerdan, Solakhay, Ayrantoken, Goturdag, Kirdag, and other volcanoes have developed along the Alat range. The mud volcanoes of North and Central Gobustan are mainly confined to Cretaceous and Paleogene sediments, and due to the low occurrence of plastic clay rocks in these sediment sections, mud volcanoes are rare and weakly active. On the contrary, to the south of these zones, that is, in South Gobustan, they are located in Pliocene sediments, and due to the presence of very thick plastic rocks in their section, mud volcanoes are widespread, and they are active volcanoes that are morphologically sharply reflected. It should be noted that in areas where plastic clay rocks with significant thickness and rheologically active properties are developed, large cones of mud volcanoes that erupt frequently are observed. The calculated gas production of mud volcanoes increases from the northern zone towards South Gobustan. Thus, while the calculated gas production of the Nabur volcano located in the Northern zone is 1500 m3/day, the calculated gas production of the Dashgil mud volcano located in South-Eastern Gobustan is 40,000 m3/day. In the central and south- ern zones of the Shamakhi-Gobustan trough, the presence of ancient rock fragments from the Oligocene-Miocene (Maykop) age rocks forming their roots in the solid waste of mud volcanoes (Cretaceous, Paleocene, Eocene), a large percentage of methane gas (97.57%), transverse elevations, and the presence of an intersection zone of longitudinal faults suggests that there is a tectonic rupture zone rich in natural gas below the base of the volcano. This is proven once again by the occurrence of gas flows in Anart (110,000 m3/day), Utalgi (50,000 m3/day), and the Touragay field (20,000 m3/day). The presence of oil films in the eruption products of mud volcanoes indicates the accumulation of oil alongside gas.