Acid Methyl Ester Research Articles

Exploring Alkali Hydroxide Influence on Calcium Titanate Formation for Application in Biodiesel Catalysts

Biodiesel has been recognized as the most widely utilized biofuel around the world due to its significant role in reducing the consumption of crude oil and lowering environmental pollution levels. By serving as a renewable alternative to fossil fuels, bioethanol helps decrease greenhouse gas emissions and contributes to a more sustainable energy future. Traditionally, alkali hydroxides like NaOH and KOH have been mainstays in biodiesel synthesis. However, their overuse can lead to unwanted byproducts and operational complexities. Since calcium titanate can occur at a strong base condition, it presents an alternative avenue worth exploring. In this study, we investigate the influence of alkali hydroxides, namely LiOH, NaOH, and KOH, on the formation of calcium titanate through hydrothermal methods, with varying heating times. We aim to understand how different hydroxides affect the synthesis process and the resultant properties of calcium titanate. We delve into the vibrational properties of Ca‒O‒Ti and Ti‒O bonds using Fourier transform infrared spectroscopy (FTIR), confirming the presence of calcium titanate (JCPDS No.42-0423) through X-ray diffractometry (XRD). This thorough characterization provides insight into the structural integrity and composition of the synthesized materials. Moreover, scanning electron microscopy (SEM) reveals the intriguing cube-like morphology of calcium titanate, offering visual evidence of its unique structure. The fatty acid methyl ester Iimpressively, our results show that calcium titanate synthesized in 7 M NaOH and KOH solutions, heated for 24 hours, emerges as a promising biodiesel catalyst. We observe fatty acid methyl ester provides the percentages of 63.67% and 90.02%, respectively, indicating the catalytic efficacy of these materials in biodiesel production. These findings not only contribute to the understanding of calcium titanate synthesis but also pave the way for a sustainable future in biodiesel production by introducing efficient and eco-friendly catalysts.

Special-point approach for optical absorption coefficient calculations on two-dimensional self-assemblies of type-II perovskite quantum dots

All-inorganic perovskite quantum dots with the usual cubic shape have emerged as a successful and low-cost alternative to electronically functional nanomaterials motivating various fields of applications, including high-efficiency photovoltaics. Here, we present an efficient and almost analytic approach for optical absorption coefficient calculation on self-assembled perovskite quantum dot films with type-II band alignment. The approach takes advantage of the special point technique for integration over the two-dimensional Brillouin zone, which minimizes the computational cost. The set of special wave-vector points is generated using the Monkhorst and Pack method. The optical absorption spectrum for phenyl-C60-butyric acid methyl ester (PCBM)/CsPbI3quantum dot films is computed, in good agreement with the experiment assuming a homogeneous linewidth of 50 meV and considering a ten special-point set. We show that light absorption in these systems is a cooperative optoelectronic property resulting from the quantum-mechanical coupling between perovskite nanocubes, leading to extended system states. The generality of this approach makes it suitable for calculating the optical absorption coefficient in a broad class of perovskite quantum dot systems.

Efficient and stable inverted perovskite solar cells enabled by homogenized PCBM with enhanced electron transport

Fullerene derivatives are extensively employed in inverted perovskite solar cells due to their excellent electron extraction capabilities. However, [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) agglomerates easily in solution and exhibits a relatively low ionization barrier, increasing charge recombination losses and charge accumulation in the interface. Here, tetramethylthiuram disulfide (TMDS) is introduced into the PCBM solution to induce the formation of reducing sulfur radicals through UV light irradiation, allowing for n doping of the PCBM material. The resulting modified PCBM layer exhibits enhanced conductivity and electron mobility, significantly suppressing charge recombination. As a result, the resulting devices incorporating TMDS achieve a champion efficiency of 26.10% (certified 25.39%) and 24.06% at a larger area (1.0 cm2) with negligible hysteresis. More importantly, the optimized devices retain 95% and 90% of their initial efficiency after 1090 h under damp heat testing (85 °C and 85% relative humidity) and after 1271 h under maximum power point-tracking conditions, respectively.

Validation of ethnopharmacological findings of Aegle marmelos (L.) Correa through phytochemical screening and bioactivity assay

For centuries, medicinal plants have been integral to human health and well-being across the world. Aegle marmelos (Rutaceae), a medicinal plant indigenous to Nepal, holds substantial ethnomedicinal use among indigenous communities in South Asian countries. Present study aimed to explore the integration of contemporary scientific analysis of the phytochemical composition and bioactivity of A. marmelos leaf extracts harvested from Nepal with traditional ethnopharmacological knowledge. Leaf extracts of A. marmelos were subjected to phytochemical analysis utilizing mass spectrometry. The extracts underwent in vitro evaluation for antimicrobial, antidiabetic, antioxidant, and toxicity activities. Hexane fraction was found to possess volatile oils, polyphenols, and tannins, while other fractions were found to have alkaloids, terpenoids, coumarins, flavonoids, glycosides, saponins, and reducing sugars. Further analysis of the hexane fraction identified 21 compounds with over 90 % accuracy. The main phytoconstituents were 9,12,15-octadecatrienoic acid methyl ester (24.25 %), hexadecanoic acid (10.89 %), methylcyclohexane (8.39 %), methyl ester (4.26 %), and caryophyllene (4.10 %). The methanol extract exhibited significant antibacterial activity against Staphylococcus aureus and Escherichia coli. Additionally, the methanol extract demonstrated pronounced cytotoxic effects against brine shrimp, with an LC50 value of 50.11 µg/mL. The 1,1-diphenyl-2-picryl hydrazyl assay revealed both methanol and acetone extract to have notable antioxidant activity, with IC50 values of 90.63 ± 1.47 µg/mL and 89.93 ± 2.52 µg/mL, respectively. Remarkably, the acetone extract displayed superior antidiabetic activity compared to acarbose, with an IC50 value of 13.50 ± 0.79 µg/mL. Our findings proves A. marmelos leaf extracts to harbor significant bioactive constituents, suggesting their potential as sources of natural compounds for applications in medicine and healthcare.

Enhancing biomass, hydrocarbon and biodiesel properties of green microalga Botryococcus braunii KMITL through gamma and UV radiation exposure.

This study investigated the effects of gamma (137Cs, 0-250Gy) and UV (UV-C, 0-12h) radiation on growth and biodiesel properties of Botryococcus braunii KMITL. For gamma radiation, maximum biomass (1.37 ± 0.02g L-1) was achieved with 50Gy, while a dose of 200Gy resulted in the highest hydrocarbon content (51.84 ± 0.20%) and yield (0.66 ± 0.01g L-1). For UV radiation, a 9h exposure produced the highest biomass (2.45 ± 0.05g L-1), hydrocarbon content (55.01 ± 1.22%), and yield (1.35 ± 0.04g L-1). Algae exposed to gamma radiation within the range of 0-150Gy exhibited C16:0 as the dominant fatty acid methyl ester (FAME), similar to those exposed to UV radiation, while algae exposed to 200-250Gy displayed C18:1n9t as the dominant FAME. High levels of gamma and UV radiation were observed to lengthen fatty acid chains and increase unsaturated fatty acids. The cetane values of biodiesel from algae exposed to gamma and UV radiation ranged from 64.55 ± 0.14-66.47 ± 0.20 and 59.43 ± 0.04-65.27 ± 0.22, respectively, all meeting standard criteria. Both gamma and UV radiation also improved the saponification value and cold flow properties of the biodiesel. These findings suggest that controlled levels of gamma and UV radiation effectively enhance hydrocarbon yields with significant implications for biofuel production.

No-Till and Crop Rotation Are Promising Practices to Enhance Soil Health in Cotton-Producing Semiarid Regions: Insights from Citizen Science

This on-farm study was conducted to assess the impact of six prevalent crop management practices adopted by growers in West Texas on various indicators of soil health. This study is a part of a citizen science project, where we collaborated with cotton growers who helped with standardized sample and data collection from 2017 to 2022. This project aimed to identify soil management practices that increase carbon sequestration, enhance biological activities, and improve overall soil health. We monitored soil moisture, soil organic matter (SOM), inorganic nitrogen (NH4+-N and NO3−-N) and other exchangeable nutrients, and soil microbial abundances as obtained via fatty acid methyl ester (FAME) in 85 fields, incorporating different management practices during the cotton growing season. In our study, volumetric moisture content (VWC) was increased by no-till, irrigation, and crop rotation, but the addition of residue decreased VWC. No-till, irrigation, and crop rotation increased SOM, but a cover crop decreased SOM. No-till and residue retention also increased microbial biomass carbon (MBC). Tillage, irrigation, and crop rotation influenced the abundance of the main microbial groups, including bacterial, fungi, and arbuscular mycorrhizal fungi (AMF). Additionally, water content, SOM, and microbial abundances are correlated with clay percentage. Our results indicate that no-till and crop rotation are the two most crucial soil management approaches for sustainable soil health. As such, implementing both no-till and crop rotation in the cropping systems has the most promising potential to increase the soil resilience in dryland cotton production in semiarid regions, thereby helping growers to maintain cotton production.

Bioactive phenolic contents of Scorzonera ketzkhowelii Sosn. ex Grossh. (Asteraceae) with comprehensive in vitro and in silico studies

This study explores the antioxidant, anti-inflammatory, and anticholinesterase properties of extracts from the natural plant Scorzonera ketzkhowelii for the first time. Additionally, it focuses on isolating phenolic compounds from the ethyl acetate sub-extract, elucidating their structures, and investigating their in-silico bioactivities. Twelve phenolic compounds were isolated and characterized from the ethyl acetate sub-extracts, including hydrangenol (1), 4-hydroxybenzaldehyde (2), luteolin (3), esculin (4), 3-O-caffeoylquinic acid ethyl ester (5), 3-O-caffeoylquinic acid methyl ester (6), kaempferol 3-O-β-glucopyranoside (7), quercetin 3-O-α-arabinopyranoside (8), 3,5-di-O-caffeoylquinic acid ethyl ester (9), thunberginol F 7-O-β-D-glucopyranoside (10), hydrangeic acid 4′-O-β-D-glucopyranoside (11), and 3-O-caffeoylquinic acid (12). The ethyl acetate sub-extracts from both aerial and subaerial parts demonstrated exceptional radical scavenging activity. Moreover, all fractions exhibited potent inhibition against COX-I and COX-II enzymes, with notable inhibitory effects observed in the ethyl acetate and dichloromethane sub-extracts against AChE. Additionally, the inhibitory effects of these compounds were assessed against various biological targets, including TNFα, COX-I, COX-II, human CYP450, and hAChE, through molecular docking studies. According to the molecular docking and dynamics studies, compound 9 emerged as particularly noteworthy across all complexes, exhibiting stable binding modes and promising interactions with key residues involved in inhibition.

Dye-Containing Polymers with π-Extened Diketopyrropyrrole Derivatives for Semi-Transparent Organic Photovoltaics.

Dye-containing polymers P1 (PEDPP-OT-BDT) and P2 (PEDPP-OT-BDTT) including a π-extended diketopyropyrrole (DPP) derivative and electron-rich thiophene fused ring units (4,8-bis((2-ethylhexyl)oxy)benzo[1,2-b:4,5-b']dithiophene for P1 and 4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b']dithiophene for P2) were synthesized as narrow band gap dyes. A π-extended DPP (EDPP-OT-BrPh), fragment of the polymers P1 and P2, was obtained by extending the π-conjugation of DPP using Ru(III)-catalyzed C-H and N-H activation reported by Gońka et al. in 2019, exhibiting a high quantum yield (ϕem=0.84) and small HOMO-LUMO gap (Eg=1.69 eV) due to the spatial overlap of the HOMO and LUMO orbitals. The solubility of the π-extended DPP was improved by introducing four 2-octylthophene side chains around the periphery of the planer dye moiety, while maintaining the high planarity of the dye molecule, which is essential to the function of optoelectronic devices. As a result, P1 and P2, polymerized with the π-extended DPP and BDT derivatives, exhibit carrier mobility of approximately 10-5 cm2/Vs in organic field-effect transistors (OFETs). In bulk heterojunction (BHJ) solar cells with [6,6]-phenyl-C61-butyric acid methyl ester (PCBM), they demonstrate a power conversion efficiency (PCE) of 1.0 % with an average transmittance (AVTs) of around 60 %.

Enhancing the production and immobilization of cell‐bound lipase from yeast‐like fungus Magnusiomyces capitatusA4C for sustainable biodiesel production in a packed bed reactor

AbstractMagnusiomyces capitatus A4C, a mycelium‐forming and lipase‐producing yeast‐like fungus, was employed in a five‐level factorial design to optimize the collective and interactive influences of carbon, nitrogen and emulsifying sources and their possible effects on cell‐bound lipase (CBL) and cell biomass production. The cell culture of M. capitatus A4C was incubated along with biomass support particles (BSPs) to immobilize the enzyme while anchoring CBL on their surfaces. Among the BSPs tested, CBL immobilized on loofah sponge under optimized conditions showed a substantial hydrolytic activity of 12.7 U mL−1 and a cell‐loading capacity of 0.61 g g−1 of BSPs. Immobilized CBL was applied for biodiesel production via transesterification and esterification. The conversion percentage of triacylglycerides was approximately 100% at 24 h with the addition of water at 1:1 (v/v). The conversion of oleic acid into biodiesel via esterification was 100% at 48 h in the presence of 15% (v/v) isooctane. Further, biodiesel production was scaled up using a packed bed reactor. The batch production of biodiesel in a packed bed reactor through transesterification was 96.2%, with a circulation flow rate of 5.5 mL min−1 for 18 h. On the other hand, oleic acid conversion into biodiesel via esterification was 99.5%, with a circulation flow rate of 5.5 mL min−1 for 24 h. Further investigation revealed that the immobilized biocatalyst exhibited higher stability with esterification (85.3% fatty acid methyl ester) after ten repeated cycles.

Multicomponent Synthesis of C(8)-Substituted Purine Building Blocks of Peptide Nucleic Acids from Prebiotic Compounds.

We have explored the reaction of a three-components mixture of aminomalononitrile, urea and α-amino acid methyl esters for the multicomponent synthesis substituted purines resembling PNA's building blocks. 2,6-diamino-purines, 6-amino-3,9-dihydro-2H-purin-2-one (iso-guanines), and 3,9-dihydro-6H-purin-6-one derivatives, selectively decorated at C(8)-position of the purine ring with different amino acid residues, were obtained from acceptable to good yields. The regio-selectivity of the transformation was controlled by the use of urea in the ternary mixture and by the annulation agent involved in the ring-closure of amino-imidazole carbonitrile intermediates. Solvent free conditions, microwave irradiation and simple one-carbon containing reagents further satisfied the major requirement of atom economy and sustainable chemistry. Due to the prebiotic nature of the three-components mixture and of annulation agents, it also embodies the possibility for the synthesis of novel PNAs bearing purine nucleobases decorated at C(8)-position of the imidazole ring as alternative RNA analogues in molecular evolution.

Temperature Effects on Seed Germination and Seedling Biochemical Profile of Cannabis Landraces

This study investigated the effect of temperature on the germination and seedling biochemical profiles of eight cannabis landraces, namely Ladysmith Ugwayi wesiZulu (L1) and Iswazi (L2), Durban Poison (H1), Bergville Ugwayi wesiZulu (B1), Natal (B2), and Iswazi (B3), and Msinga Ugwayi wesiZulu (M1) and Iswazi (M2). Seed viability, germination rate, and germination percentage were evaluated along with seedling amino acids, carbohydrates, and fatty acids methyl esters (FAMEs) under day/night temperature regimes of 20/15 °C, 30/25 °C, and 40/35 °C. Results showed a significant effect (p < 0.001) of temperature on germination percentage, rate, and biochemical profiles of cannabis landraces. Landraces L1, B1, H1, B2, and M1 had higher germination at 20/15 °C, while B3, M2, and L2 performed better at 30/25 °C. Biochemical profiles varied with temperature and landraces. Amino acid content increased with temperature but did not correlate with germination indexes. Carbohydrates and FAMEs decreased with rising temperature, peaking at 30/25 °C. FAMEs strongly correlated with germination indexes, linking lipid composition to seed performance. Sorbitol positively correlated with germination, while glucose and fructose showed indirect correlations. This study underscores the impact of temperature on germination and the biochemical profiles of cannabis landraces, highlighting the importance of considering genotype-specific responses in varietal selection.

Reducing Interfacial Recombination in Inverted Perovskite Solar Cells With Selenophene-Substituted PCBM: Comparison With Thiophene and Furan Substitution.

Reducing the interfacial recombination and improving the charge transfer capability of charge transport layers are effective strategies to enhance the efficiency and stability of perovskite solar cells (PSCs). This study evaluates, for the first time, the effects of selenophene substitution in the chemical structure of phenyl-butyric acid methyl ester (PCBM) on the performance and stability of inverted PSCs. Selenophene substitution was compared to thiophene and furan substitutions, and the reference PCBM without chalcogenophene moiety. Additionally, this study investigates the differences between using the fullerene cages C70 and C60 in the PCBM chemical structure. The photovoltaic results demonstrate that, with an adequate control of the thickness of the electron transport layer (ETL), incorporating the selenophene moiety in the structures of fullerenes enhances the photovoltaic parameters of PSCs. This improvement results from the reduction in trap-assisted recombination, an increase in electron mobility, and the improved charge extraction processes. The use of C70, as opposed to C60, allows for the preparation of a series of ETLs with comparable thicknesses, although slightly lower efficiencies. This feature facilitates a systematic comparative analysis focused on variations in the electron properties of ETLs, thereby avoiding the inclusion of issues related to thickness and charge recombination processes.

Effect of Ultrasonic Waves on Aspire Biodiesel and Comparison of Its Properties with Petroleum Diesel

This study aimed to determine the effect of ultrasonic sound waves on modifying the chemical structure of biodiesel to bring its physical properties closer to petroleum diesel. In this direction, safflower oil was selected because its fatty acid composition is similar to fatty acid esters of petroleum diesel and is a sustainable source. Refined safflower oil, the free fatty acid content of which was determined, was reacted with methanol under NaOH catalyst to perform the transesterification reaction. After biodiesel production, samples were incubated in an ultrasonic bath for 60, 120, and 180 minutes. FTIR, density, free fatty acid content, flash point, viscosity, and cloud point analyses investigated the effect of incubation times on biodiesel's chemical structure and properties. FTIR spectra showed that ultrasonic sound waves partially decomposed fatty acid methyl esters and increased the number of volatile components in biodiesel. The flash point of biodiesel has been associated with a decrease of 89°C, and the low flash point is expected to increase fuel efficiency. Kinematic viscosity values were measured in the 3.4583-3.5115 mm²/s range, and density values were measured in the 0.8820-0.8872 g/ml range. These values show that biodiesel complies with national and international standards. As a result, the ultrasonic bath process applied to biodiesel showed a similar result to chemical modification methods by affecting the structure of fatty acid chains. Thus, it brought the physical properties of biodiesel closer to petroleum diesel. It is seen that this method is a more efficient alternative for biodiesel production because it does not use additional chemicals, and the process is faster. In conclusion, by increasing the production of the drought-resistant safflower plant, sustainable energy resources will be contributed, while its waste can be evaluated as animal feed. Ultrasonicated safflower biodiesel can also be used as an efficient, environmentally and mechanically friendly alternative fuel source.

Nanoporous Carbon-Supported Bimetallic (Ni, Cu, and Fe)-Mo Catalysts for Partial Hydrogenation of Biodiesel.

Upgrading biodiesel or hydrogenated fatty acid methyl esters (H-FAMEs) by partial hydrogenation is a second-generation biofuel with high specific fuel characteristics, such as superior cold flow properties, higher oxidative stability, and lower hazardous gas emissions, allowing this biofuel to provide excellent fuel properties, over conventional biodiesel. This study assessed the potential of using nanoporous carbon produced from cattail leaves (CL) as an alternative catalyst support. We synthesized various catalysts including monometallic Mo/NPC, Ni/NPC, Ce/NPC, and Fe/NPC catalysts, as well as bimetallic molybdenum-based catalysts doped with nickel, copper, or iron for the partial hydrogenation of soybean biodiesel. The NPC support demonstrated a surface area (S BET) of approximately 1,323 m2g-1, which greatly increases the catalytic activity through the efficient dispersion of catalyst active sites. The partial hydrogenation reaction of soybean FAME over the MoNi/NPC catalyst obtained the highest catalytic activity with enhanced oxidation stability from 3 to 14 h, and the cloud point and pour point increased from 2 to 13 °C and -1 to 10 °C, respectively. Hence, the selection of catalysts is crucial due to their impact on the feasibility of the process and its economic viability. This article focuses on highlighting the effectiveness of a highly promising catalyst for partial hydrogenation as well as examining the variables that influence the primary reaction pathway.

Investigating the effects of microplastics on the metabolism of Trematomus bernacchii from the ross sea (Antarctica)

Microplastic pollution is a growing environmental issue, even reaching remote areas like the Arctic and Antarctic, posing threats to biodiversity and food chains. The present research represents a pioneering endeavor aimed at exploring the relationship between lipids and microplastics in 20 wild specimens of Trematomus bernacchii from the Ross Sea (Antarctica). Fish were grouped in MPs-ingested and MPs-free based on whether they had ingested microplastics. Raman spectroscopy revealed that contaminated fish samples contained from one to three different types of polymeric fibers (1.4 items/specimen, ± = 0.7), specifically, polyester (PES), polypropylene (PP), and polyethylene terephthalate (PET). Gas chromatography-mass spectrometry (GC–MS) and gas chromatography-flame ionization detection (GC-FID) techniques were employed for the study of the lipid composition in term of fatty acids methyl esters (FAMEs). Fifty different FAME compounds were identified and quantified in the lipid fraction extracted from the muscle tissues of the selected fish samples. Polyunsaturated fatty acids (PUFAs) are the most abundant family of fatty acids in T. bernacchii species with eicosapentaenoic (C20:5ω3) and docosahexaenoic (C22:6ω3) acids as main components. In detail, PUFA class accounted for 46.78 ± 6.82% and 44.62 ± 4.86% of the total fatty acid composition in MPs-ingested and MPs-free groups, respectively. The contents of the monounsaturated fatty acids (MUFAs) and saturated fatty acids (SFAs) varied from 27.93% to 31.15% and from 24.23% to 25.05% in MPs-ingested and MPs-free fish samples, respectively. Based on Mann-Whitney test results (p < 0.05), there was no significant difference from a statistical point of view between two groups of fishes. Additionally, nutritional quality indices exhibited comparable values between groups. Results showed that no significant differences were found in the fatty acids distribution between the two groups. This indicates that the lipid composition of wild fish that are naturally exposed to plastic pollution remains unchanged and could still have beneficial effects on human health.

Two Photocatalytic Pathways for Reductive Dearomatizations of N‐Arylformylindoles by a Visible‐Light Triplet Organocatalyst

AbstractA visible‐light triplet photocatalyst 5‐acetyl‐2‐mercapto‐benzoic acid methyl ester (AcBSH) was developed through introducing acetyl into benzenethiolate to improve the efficiency of intersystem crossing (ISC) and using o‐methoxyformyl to increase the molar extinction coefficient. In the photocatalytic system of AcBSH, the reductive dearomatization of N‐arylformylindoles is achieved to afford the desired indolines in moderate to excellent yields, including both indoles without (1) and with 2‐substituent (2). The 2‐substituent is a steric hindrance for the conjugation between benzoyl and indole moiety, and makes indole 2 and indole 1 exhibit different reduction potentials (Ered) and different triplet energy levels (ΔET). Thereby, two kinds of substrates undergo primarily two photocatalytic pathways: i) successive SET/protonation pathway, which merging photosensitization via triplet‐triplet energy transfer (EnT) and photoinduced SET for substrates 1, and ii) single electron transfer (SET) from the triplet photocatalyst and a concerted hydrogen atom transfer (HAT) process for substrates 2.

Response surface optimization of a single-step castor oil-based biodiesel production process using a stator-rotor hydrodynamic cavitation reactor.

In order to combat environmental pollution and the depletion of non-renewable fuels, feasible, eco-friendly, and sustainable biodiesel production from non-edible oil crops must be augmented. This study is the first to intensify biodiesel production from castor oil using a self-manufactured cylindrical stator-rotor hydrodynamic cavitation reactor. In order to model and optimize the biodiesel yield, a response surface methodology based on a 1/2 fraction-three-level face center composite design of three levels and five experimental factors was used. The predicted ideal operating parameters were found to be 52.51°C, 1164.8rpm rotor speed, 27.43min, 8.4:1 methanol-to-oil molar ratio, and 0.89% KOH concentration. That yielded 95.51% biodiesel with a 99% fatty acid methyl ester content. It recorded a relatively low energy consumption and high cavitation yield of 6.09 × 105J and 12 × 10-3g/J, respectively. The generated biodiesel and bio-/petro-diesel blends had good fuel qualities that were on par with global norms and commercially available Egyptian petro-diesel. The preliminary cost analysis assured the feasibility of the applied process.

Aspects of Reaction Engineering for Biodiesel Production

Biodiesel is a non-toxic, drop-in liquid transportation fuel that is amenable to continuous production from sustainable biomass resources using catalytic technologies. A diverse range of catalysts and reactor technologies have been experimentally investigated and computationally modelled, for producing biodiesel (fatty acid methyl esters) from oil feedstocks by their esterification or transesterification with short-chain alcohols. Solid-acid and base catalysts are attractive for biodiesel production from renewable oil feedstocks due to their ease of separation from the desired biodiesel and glycerol by-product, use of Earth’s abundant elements, and suitability in continuous processes. Here, we review the technical challenges and opportunities in designing catalytic reactor systems for biodiesel production.

Fungal Biostarter and Bacterial Occurrence of Dry-Aged Beef: The Sensory Quality and Volatile Aroma Compounds after 21 Days of Aging

In this study, we decided to test the hypothesis that the fungal biostarter M. flavus used during a 21-day beef dry-aging process significantly impacts the composition of other microorganisms, the profile of volatile compounds, meat hardness characteristics, and, consequently, the sensory quality. The experiments were performed on samples derived from animals crossbred between Holstein–Fresian cows and meat breed bulls. Two groups of samples were studied, including the control group, without biostarter, and a group inoculated with the M. flavus biostarter. Both sample groups were seasoned for 21 days in the dry-aging fridge. The physicochemical parameters (pH, color parameters), the chemical composition of muscle, the determination of the shear force, the profile of volatile compounds (VOCs), and the sensory quality were evaluated after aging. During this study, classical microbiological methods were used to investigate the influence of fungal biostarters on the growth and survival of bacteria and other fungi (e.g., yeasts) during the dry-aging process of beef (DAB). The M. flavus biostarter improved the sensory quality of DAB, allowing high sensory quality to be achieved after just 21 days. This is likely due to the diverse VOCs produced by the fungus, including 1-tetradecanol, 2-nonenal, trans-2-undecenoic acid, and the following esters: formic acid hexyl ester, 10-undecenoic acid methyl ester, and 4-methylpentanoic acid methyl ester. The presence of the biostarter had no significant effect on the number of the bacteria or the survivability of the L. monocytogenes on the meat’s surface in laboratory conditions.

Recyclability of Zinc Palmitate-Based Composites in Fatty Acid Methyl Ester Production from Oil Feedstocks at Varied Acidity.

Zinc hydroxide nitrate (Zn5) is one of the layered metal hydroxide materials, which has been extensively reported as an effective bifunctional catalyst for biodiesel production from acidic oils. This report gives a comprehensive summary of the reactivity of Zn5 in the methanolysis of various oil feedstocks, plant oils, free fatty acids, and other acidic oils. Notably, as evidenced by this work, Zn5 is highly effective in converting acidic oils [palmitic acid/palm oil (PO)] to fatty acid methyl ester (FAME or biodiesel) at high yields ranging from 80 to 95%, withstanding acid content up to 10% without soap formation. The high FAME yields result from complex methanolysis and hydrolysis processes, e.g., transesterification of triglycerides in the PO, esterification of palmitic acid, and hydrolysis of the triglycerides. Despite this, Zn5 is nonrecyclable because it is unstable in the reaction media and transforms into zinc hydroxide nitrate/zinc palmitate (Zn5/ZnP) composites. The Zn5/ZnP composites were suitable for use in FAME production from PO at 100 °C for 2 h by using a methanol-to-oil molar ratio of 30:1, yielding high FAME yields of 97 and 70.7% in the first and fourth cycles, respectively. This study added better insight into how to effectively produce FAME from oil feedstocks of varying acidity by using zinc layered hydroxide- or zinc carboxylate-based materials.