High-value Products Research Articles

Growth and metabolism regulation of cinnamic acid and its derivatives to Auxenochlorella pyrenoidosa

Auxenochlorella pyrenoidosa's industrial utility is closely associated with the concentration of high-value products. This study focuses on the effects of cinnamic acid (CA) and its derivatives, which known as secondary metabolites in higher plants and effective plant growth regulators, on the growth and metabolic profiles of A. pyrenoidosa. It was discovered that CA and its derivatives significantly enhance the biomass of A. pyrenoidosa under conditions of 10 mg/L over 48 h or 100 mg/L over 120 h. Cells treated with 10 mg/L CA exhibited lower oxidative stress and maintained robust metabolic activity. Metabolic pathways, including those for carbohydrates, lipids, small peptides, and cofactors, were stimulated, leading to the accumulation of a wide array of bio-products, notably high-value products such as α-linolenic acid, cis-4,7,10,13,16,19-docosahexaenoic acid (DHA), nicotinamide adenine dinucleotide plus hydrogen (NADH), glutathione, and vitamins B2/B3. This study demonstrates that CA and its derivatives are good nutritional enhancers for cultivating A. pyrenoidosa, highlighting their potential for broad application in biotechnological industries.

Preparation and characterization of carboxymethyl microcrystalline cellulose from pineapple leaf fibre

Highly functional and robust biobased materials are still in research to produce valuable composites for various applications. The literature shows the gap of new raw biobased materials in market which can functionally tuned and structurally modified for development of 2d/3d architectures. Thus, in the present study, very cheap, easily available agricultural waste, pineapple leaf fiber (PL-raw) was used for the isolation of microcrystalline cellulose (PL-MCC) and further functionalized using upscaled chemical approach to carboxymethyl microcrystalline cellulose (PL-CMMCC). Very advanced techniques like Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), X-ray diffraction analysis (XRD), and differential scanning calorimetry (DSC) served to characterize the raw material, high crystalline PL-MCC, and modified carboxy methyl MCC. FTIR determined presence of different absorbed peak at approximately 1620.2 cm−1, and at 1423.8 cm−1, carboxyl groups were assigned to PL-CMMCC. On the other hand, the XRD findings verified that PL-CMMCC’s crystalline structure has decreased. Analysis by SEM revealed a damaged surface morphology for PL-CMMCC. Following chemical treatments, the EDX analysis revealed that each fiber sample contained a highly pure cellulose elemental composition. Thus, results explain the utilization of agricultural waste, pineapple leaf fiber to high valuable products like highly crystalline PL-MCC, in addition further modification of PL-MCC could leads to formation of highly functional material that could be used for other applications too in future.

Continuous flow versatile conversion of furfural to valuable end products catalyzed by commercial Pd/C

The conversion of furfural has gained significant attention in recent years due to its potential for transforming this basic chemical into a wide range of valuable end products, such as alcohols, amines, acids, and biopolymers. This contribution aims to demonstrate the versatility and potential of continuous flow processes combined with commercial Pd/C catalysts for converting furfural into high value-added chemicals, including furfuryl alcohol, tetrahydrofurfuryl alcohol, and furfurylimine. By optimizing reaction conditions, high product yields (60–90%) were achieved, marking the first literature example of continuous flow conversion of furfural into diverse products, such as alcohols and imines. This work advances the production of high-value products using propanol as a hydrogen donor, with high yields and selectivity, employing commercial catalysts in a scalable continuous process.

Agro-Based nanoparticles composite: A novel approach for enhanced ballistic applications

The field of material science has witnessed a paradigm shift with the emergence of agro-based nanoparticles composites demonstrating remarkable potential for advanced applications. Agricultural by-products, such as cellulose, lignin, and chitin, are selected as the base materials due to their abundance, renewability, low adverse environmental impact and acceptable mechanical properties. The developed composites exhibits superior specific mechanical properties compared to traditional materials. This review explores the synthesis, characterization, and application of agro-based nanoparticles in composites development for ballistic purposes. The eco-friendly nature and synthesis of agro-based composite aligns with the current sustainability goals, offering a green alternative to conventional materials being used in ballistic applications. The utilization of agricultural by-products not only mitigates environmental concerns but also promotes the circular economy by repurposing waste materials into high-value products. This review presents a novel approach in the field of ballistic materials by harnessing the potential of agro-based nanoparticles composites. The superior specific mechanical properties make this composite material a promising candidate for ballistic applications, thereby, opening avenues for sustainable advancements in defense and security technologies. Keywords: Agro-based, Nanoparticles, Composites, Green Technology, Ballistic Application.

Insights into lignin bioconversion: lignin-derived compounds treatment of a novel marine fungus K-2.

The potential for the efficient conversion of lignocellulosic biomass has been extensively explored to produce a wide range of bioproducts. Many approaches have been sought for the deep conversion of lignin to generate products that are toxin-free and beneficial for processing into high-value-added components. This study reported a fungus isolated from the deep sea with strong synthesis of multiple lignocellulases, conversion of lignin and guaiacol (0.1%) by 71.6% and 86.1% within 9 days at 30 °C respectively, and outstanding environmental adaptability (20-50 °C and pH 3-8). Metabolic pathway profiling showed that this fungus utilized lignin to rapidly activate multiple ring-opening reactions including the 2,3- and 3,4-cleavage pathways, with the 2,3-cleavage pathway predominating after 5 days. Conversion of metabolic intermediates confirmed the superb potential of this strain for lignin treatment. Meanwhile, its shikimic acid pathway was metabolically active under lignin. This further expands the potential to produce valuable bioproducts during lignin treatment, especially under ambient conditions, which can significantly enhance high-value precursor compound production. © 2024 Society of Chemical Industry.

Effects of spray drying and freeze drying on the protein profile of whey protein concentrate.

Whey protein concentrate (WPC) is consumed for its high protein content. The structure and biological functionality of whey proteins in WPC powders may be affected by the drying technique applied. However, the specific impact of spray drying and freeze drying on the overall protein profile of whey protein derived from sweet whey streams at scale is unknown. Herein, we examine the effects of commercial-scale freeze drying and spray drying on WPC to determine which method better preserves bioactive whey proteins, with the goal of helping the dairy industry create high-value products that meet the growing consumer demand for functional dairy products. WPCs were produced from pasteurized liquid whey using either a commercial spray dryer or freeze dryer. A variety of analytical techniques, including enzyme-linked immunosorbent assay, polyacrylamide gel electrophoresis, and bottom-up proteomics using liquid chromatography-tandem mass spectroscopy were used to identify, quantify, and compare the retention of bioactive proteins in WPC before and after spray drying and freeze drying. In addition, the extent of denaturation was studied via solubility testing, differential scanning calorimetry, and hydrophobicity assessment. There was little to no difference in the retention or denaturation of key bioactive proteins between spray-dried and freeze-dried WPC powders. There was a higher percentage of select Maillard modifications in freeze-dried and spray-dried powders than in the control. The lack of significant differences between spray drying and freeze drying identified herein indicates that freeze drying does not meaningfully improve retention of bioactive proteins compared with spray drying when performed after multiple pasteurization steps. PRACTICAL APPLICATION: This study aimed to provide insight into the impacts of spray drying versus freeze drying on whey proteins. Overall, our results indicate that for commercial dairy processing that involves multiple rounds of pasteurization, freeze drying does not meaningfully improve the retention of bioactive proteins compared with spray drying. These findings may help the food and dairy industry make informed decisions regarding the processing of its whey protein products to optimize nutritional value.

Effect of calcination temperature on the activity of basalt tailings for the lightweight geopolymer from microwave curing

Basalt, the most widely distributed alumino-silicate volcanic rock on Earth, is commonly utilized in construction aggregate area. The challenge lies in how to utilize the tailings produced during mining processes to create high-value products through energy-efficient and environmentally-friendly means. A previous study has already shown the use of basalt tail powder as raw material for lightweight geopolymer materials supported microwave curing, without an extensive focus on mechanical properties, in turn known to be significantly affected by the reactivity of constituents. Here, calcination operations are discussed in their impact on the activity of basalt for lightweight geopolymer from microwave curing. Additionally, the thermal characteristics of basalt during temperature were analyzed using differential scanning calorimetry, scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction analyses were employed to examine the micromorphology, chemical structure, phase compositions, and reaction degree of basalt and its alkali activated products. The results prove that basalt is a sustainable raw material for geopolymers, with properties already optimized without calcination, in turn determining a slight increase only at 750 °C (resulting in compressive strength >7 MPa, with a porosity of 30 %). The effect mechanism of calcination temperature on the activity of basalt tailings for the lightweight geopolymer from microwave curing is also discussed.

Ag Nanoparticles-Confined Doped within Triazine-Based Covalent Organic Frameworks for Syngas Production from Electrocatalytic Reduction of CO2.

Electrocatalytic CO2 reduction reaction (CO2RR) emerges as a promising avenue to mitigate carbon emissions, enabling the capture and conversion of CO2 into high-value products such as syngas with CO/H2. One of the crucial aspects lies in the tailored development of durable and efficient electrocatalysts for the CO2RR. Covalent organic frameworks (COFs) possess unique characteristics that render them attractive candidates for catalytic applications. However, the relationship between structure and performance still requires further exploration; especially, most COFs with such properties are limited to COFs containing specific groups such as phthalocyanine or porphyrin groups. Here, we custom-synthesize two azine-linked nitrogen-rich COFs constructed from triazine building blocks, which are doped with ultrafine and highly dispersed Ag nanoparticles (Ag@TFPT-HZ and Ag@TPT-HZ). Thus-obtained COFs can serve as electrocatalysts for the CO2RR, and a comprehensive investigation has been conducted to uncover the intricate structure-performance relationship within these materials. Notably, Ag@TFPT-HZ exhibits superior CO selectivity in the electrocatalytic CO2RR, achieving a FECO of 81% and a partial current density of 7.65 mA·cm-2 at the potential of -1.0 V (vs reversible hydrogen electrode (RHE)). In addition, Ag@TPT-HZ as an electrocatalyst can continuously produce syngas with a CO/H2 molar ratio of 1:1, an ideal condition for methanol synthesis. The observed distinct performance between these two COFs is attributed to the presence of O atoms in TFPT-HZ. These O atoms facilitate a higher loading capacity of Ag nanoparticles (11 wt %) and generate a greater number of active sites, thereby enhancing electrochemical activity and promoting faster reaction kinetics. Therefore, two tailor-made two-dimensional (2D) nitrogen-rich COFs with various active sites as electrocatalysts can exhibit different outstanding electrocatalytic performances for CO2RR and possess high cycling stability (>50 h). This work offers valuable insights into the design and synthesis of electrocatalysts, particularly in elucidating the intricate relationship between their structure and performance.

Specific Photocatalytic C-C Coupling of Benzyl Alcohol to Deoxybenzoin or Benzoin by Precise Control of Cα-H Bond Activation or O-H Bond Activation by Adjusting the Adsorption Orientation of Hydrobenzoin Intermediates.

Benzyl alcohol (BA) is a major biomass derivative and can be further converted into deoxybenzoin (DOB) and benzoin (BZ) as high-value products for industrial applications through photocatalytic C-C coupling reaction. The photocatalytic process contains two reaction steps, which are (1) the C-C coupling of BA to hydrobenzoin (HB) intermediates and (2) either dehydration of HB to DOB or dehydrogenation of HB to BZ. We found that generation of DOB or BZ is mainly determined by the activation of Cα-H or O-H bonds in HB. In this study, phase junction CdS photocatalysts and Ni/CdS photocatalysts were elaborately designed to precisely control the activation of Cα-H or O-H bonds in HB by adjusting the adsorption orientation of HB on the photocatalyst surfaces. After orienting the Cα-H groups in HB on the CdS surfaces, the Cα-H bond dissociation energy (BDE) at 1.39 eV is lower than the BDE of the O-H bond at 2.69 eV, therefore improving the selectivity of the DOB. Conversely, on Ni/CdS photocatalysts, the O-H groups in HB orient toward the photocatalyst surfaces. The BDE of the O-H bonds is 1.11 eV to form BZ, which is lower than the BDE of the Cα-H bonds to the DOB (1.33 eV), thereby enhancing the selectivity of BZ. As a result, CdS photocatalysts can achieve complete conversion of BA to 80.4% of the DOB after 9 h of visible light irradiation, while 0.3% Ni/CdS photocatalysts promote complete conversion of BA to 81.5% of BZ after only 5 h. This work provides a promising strategy in selective conversion of BA to either DOB or BZ through delicate design of photocatalysts.

Temperature-dependent highly active LaCaMgAl2O4 catalyst effect on carbon nanomaterial and hydrogen generation from polymethyl methacrylate plastic

The increasing accumulation of waste polymethyl methacrylate (PMMA) plastics presents a significant environmental challenge, while the demand for renewable energy sources continues to rise. Thermochemical recycling is a prospective technique for converting waste plastics into high-value chemicals, both economically and environmentally. In this work, the catalytic pyrolysis of waste PMMA plastics over LaCaMgAl2O4 nanosheets (NSs) catalyst is being investigated for its potential to produce hydrogen and carbon nanotubes (CNTs) in a two-stage fixed-bed reactor. The yield and purity of the gaseous products, as well as carbon deposition, concerning the effects of temperature during the catalysis process. Additionally, a small portion of LaCa was incorporated into the MgAl2O4 composite in the pre-catalysts under investigation. Analyzing the physicochemical properties of the carbon nanomaterials that form provides valuable insights into the workings of different catalysts. It's noteworthy that LaCaMgAl2O4 NSs showed such large yields of H2 (82.71 vol% H2) and CNTs (388 mg g−1) at 750 °C. The LaCaMgAl2O4 NSs catalyst's impressive ability to produce CNTs and H2 gas at high yields underscores its efficacy and potential for real-world catalytic pyrolysis applications. This study emphasizes the Nanocatalyst's potential for large-scale catalytic pyrolysis operations, providing a workable and efficient way of converting waste plastics into high-value products and renewable energy.

Advances in microalgae-based lutein production and extraction: enhancing bioavailability and applications in health and industry

BackgroundNatural lutein, a bioactive xanthophyll, is widely used in pharmaceuticals, nutraceuticals, aquaculture, and cosmetics due to its broad health benefits, especially in protecting ocular health and chronic and acute syndromes. Microalgae have become a preferred sustainable platform for high-value lutein production, surpassing marigold petals in content (∼2 mg g−1) and consistency. MethodsThis review highlights advancements in upstream lutein production and downstream extraction techniques, focusing on scalable and sustainable bioprocesses. Under optimal conditions, microalgae cultivation in open and closed reactors for 2–4 weeks is examined. Comparative yields among studies are analyzed, detailing which technologies and their combinations offer superior yields for commercial production. Significant FindingsMicroalgae demonstrate high lutein content (∼10–17 mg g−1) and productivity (2–7 mg L−1 d−1). The review identifies key advancements in smart delivery systems and bioavailability enhancement strategies, which are novel aspects of lutein research. The review aims to expand lutein distribution and its health benefits by addressing production challenges, market potential, and commercial opportunities. Aligning with Sustainable Development Goals (SDGs), the review promotes good health (SDG 3), economic growth (SDG 8), industry innovation (SDG 9), and climate action (SDG 13).

A Novel Algal–Algal Microbial Fuel Cell for Enhanced Chemical Oxygen Demand Removal

To enhance the removal of COD (Chemical Oxygen Demand) by microalgae, this study constructed a novel microalgae–microalgae microbial fuel cell system (AA-MFC). It investigated the coupling relationship between the COD treatment efficiency at the anode and the production of high-value microalgal products at the cathode, as well as explored the effects of different initial inoculum densities and light–dark cycles. The experiment first measured the operational performance of the newly constructed AA-MFC in open-circuit and closed-circuit modes, demonstrating that this novel AA-MFC could start up rapidly within 32 h and operate stably. The results showed that the AA-MFC enhanced the removal of COD and the growth of microalgae biomass at the anode while maintaining stable power generation. When the initial inoculation density of the anode was 1.2 × 108 cell/cm2 and the light–dark cycle time was 18:6 h, the AA-MFC had the most obvious promoting effect on the COD removal of the anode. Compared with normal culture conditions, the COD removal rate increased by 26.0% to 96.1%. These results indicate that the AA-MFC can not only effectively remove pollutants, but also promote the accumulation of high-value microalgae biomass.

Mycelial mass, microbial lipids and γ-linolenic acid (GLA) by Cunninghamella elegans cultivated on agro-industrial residues

In the current study, the Zygomycetes fungus Cunninghamella elegans NRRL Y-1392 was evaluated for its ability to grow in extracts derived from dried and ground agricultural residues, such as mushroom stalks and roots from hydroponically cultivated lettuces and produce poly-unsaturated fatty acids (PUFA) and γ-linolenic acid (GLA) rich lipids. Initially, the compositions of stalks and lettuce roots were analysed, and the fungus was batch-flask cultivated on six different commercial semi-defined substrates containing different sugars detected in stalks and roots to evaluate its catabolic ability. C. elegans was capable to assimilate all sugars, but at a lower rate in the case of arabinose. Subsequently, C. elegans was cultivated on tailor-made semi-defined commercial substrates, resembling hydrolysates containing carbohydrates found in mushroom stalks, under both nitrogen-excess and nitrogen-limited conditions, and resembling that of hydrolysates of roots, under nitrogen-excess conditions. Based on the results, under nitrogen-excess conditions, in the case of media resembling stalks hydrolysates, higher production values for biomass, PUFAs, and GLA were observed (20.3 g/L, 1906 mg/L, 668 mg/L), accompanied by high productivity values due to short cultivation periods, while under nitrogen limitation, high lipid accumulation (lipid in dry cell weight =48%, w/w) was presented, and lipids rich in oleic acid were produced. Finally, the fungus was cultivated on a medium derived from hot water-extraction applied to mushroom stalks, enriched with organic nitrogen sources. The fungus was successfully grown on the sugar-rich water-extract derived from mushroom stalks, resulting in dry biomass of 14.5 g/L, lipids of 1.8 g/L, with 15% (w/w) of GLA in cellular lipids.

Fabrication of Nanofiber Membranes from Waste-Expanded Polystyrene (EPS) Combined with Zinc Oxide Nanoparticles (ZnO NPs) and its Photocatalytic Activity

Society must face the challenge of creating high-value products from recycled waste polymers. This research focuses on the synthesis of nanofiber membranes from waste-expanded polystyrene (EPS) using electrospinning. Zinc oxide nanoparticles (ZnO NPs) enhance the photocatalytic activity of the fiber membrane. ZnO is a more useful alternative to TiO2 as a form of photocatalyst for degrading contaminants in water. This study systematically investigated the effects of varying amounts of ZnO NPs on fiber membrane nanostructure and photocatalytic activity. Methylene blue was used to measure the photocatalytic efficiency of fiber membranes, as they are commonly used in textile wastewater and exposed to ultraviolet light for 20 h. The results showed that the fiber membrane containing ZnO NPs with a concentration of 1 % effectively degraded methylene blue. HIGHLIGHTS The EPS/ZnO nanofiber produced using electrospinning was characterized using SEM-EDX, FTIR, and Raman spectroscopy UV-Vis spectrophotometer testing proves that the EPS/ZnO nanofiber has photocatalytic activity capabilities that can remove organic contaminants The EPS/ZnO 1 % shows the highest efficiency; 45 % of methylene blue was degraded within 20 h of irradiation GRAPHICAL ABSTRACT

One-pot synthesis of Ir subnanosized clusters supported on MWW nanosheets as effective catalysts for C-C bond hydrogenolysis

The rational design synthesis of metal catalysts with high dispersion and ordered structure is a challenging subject in materials chemistry and heterogeneous catalysis. In this study, we report one-pot synthesis of Ir subnanosized particles supported on MWW nanosheets and their application in hydrogenolysis of decalin. Here, it has been found that C-C bond cleavage occurs via a synergistic carbocation and carbene mechanism on Ir-containing catalysts, and via carbocation in the case of solid acids. The combination of optimal acidic and metallic site characteristics in the subnanosized Ir supported on MWW nanosheets Pill_Ir-ZN_150 sample contributes to the high activity of the final catalysts. We expect that these Ir catalytic systems will open up more opportunities for hydrogenolysis of naphthenics to high-value products.

Simultaneous preparation of high-purity Si and eutectic Si-Nd alloy utilizing Nd2O3-containing waste slag and diamond-wire sawing silicon waste

Nd2O3-containing waste slag (NCWS) and diamond-wire sawing silicon waste (DSSW) are important rare earth and Si secondary resources, respectively. Currently, NCWS and DSSW are recycled respectively by at least two different routes, which is not efficient and increases the burden on the environment. The present study proposed a novel technical route for preparing high-purity bulk Si and eutectic Si-Nd alloy simultaneously using NCWS and DSSW as raw materials, depending on the concept of using waste to treat waste. The new technical route has only two steps: initially, raw Si-Nd alloys were obtained by extracting Nd from NCWS utilizing DSSW as a low-cost reductant, and the impurity, oxygen, in the DSSW was effectively removed utilizing NCWS; the highest extraction rate of Nd from NCWS reached 68.3%, and the oxygen removal rate in DSSW was 99.89%; in the subsequent step, the obtained raw Si-Nd alloys were separated and purified to produce high-purity bulk Si (＞99.98%) and eutectic Si-Nd alloy (＞99%) through a physical and clean method-electromagnetic directional crystallization. This novel route is considered effective and environmentally-friendly for the sustainability of rare earth and Si resources, because no gas and liquid wastes discharged throughout the whole route, and two high value products can be prepared simultaneously using two wastes.

Selective Electrooxidation of Crude Glycerol to Lactic Acid Coupled With Hydrogen Production at Industrially-Relevant Current Density.

Transforming glycerol (GLY, biodiesel by-product) into lactic acid (LA, biodegradable polymer monomer) through sustainable electrocatalysis presents an effective strategy to reduce biodiesel production costs and consequently enhance its applications. However, current research faces a trade-off between achieving industrially-relevant current density (>300mA cm-2) and high LA selectivity (>80%), limiting technological advancement. Herein, a Au3Ag1 alloy electrocatalyst is developed that demonstrates exceptional LA selectivity (85%) under high current density (>400mA cm-2). The current density can further reach 1022mA cm-2 at 1.2V versus RHE, superior to most previous reports for GLY electrooxidation. It is revealed that the Au3Ag1 alloy can enhance GLY adsorption and reactive oxygen species (OH*) generation, thereby significantly boosting activity. As a proof of concept, a homemade flow electrolyzer is constructed, achieving remarkable LA productivity of 68.9mmolh-1 at the anode, coupled with efficient H2 production of 3.5 Lh-1 at the cathode. To further unveil the practical possibilities of this technology, crude GLY extracted from peanut oil into LA is successfully transformed, while simultaneously producing H2 at the cathode. This work showcases a sustainable method for converting biodiesel waste into high-value products and hydrogen fuel, promoting the broader application of biodiesel.

Perubahan Komponen Kimia Fungsional pada Umbi, Tepung, dan Beras Analog Ubi Jalar Ungu

The purple sweet potato tuber, rich in functional chemical components, offers potential for development into high-value products such as flour, which can then be processed into analog rice. This research aims to evaluate the changes in functional chemical components–namely moisture, ash, protein, fat, carbohydrates, anthocyanin, and β-carotene–along with antioxidant activity during the processing of purple sweet potato tubers into flour and analog rice. The chemical composition of the tubers was found to be as follows: moisture content of 78.00% on a wet basis (wb), ash content of 9.70% on a dry basis (db), fat content of 5.47% (db), protein content of 26.93% (db), carbohydrate content of 58.41% (db), anthocyanin content of 31.79 mg/100 g (db), β-carotene content of 17.73 mg/100 g (db), and antioxidant activity of 65.70%. The composition of the resulting flour included water (6.71% wb), ash (2.40% db), fat (1.06% db), protein (3.80% db), carbohydrate (92.75% db), anthocyanin (3.47 mg/100 g db), β-carotene (1.51 mg/100 g db), and antioxidant activity (45.59%). The chemical content of the analog rice was as follows: water (8.43% wb), ash (1.78% db), fat (1.62% db), protein (4.13% db), carbohydrate (92.50% db), anthocyanin (0.71 mg/100 g db), β-carotene (1.05 mg/100 g db), and antioxidant activity (8.38%). Processing the tubers into flour resulted in a reduction of fat, protein, anthocyanins, β-carotene, and antioxidant activity, while carbohydrate content increased. Similarly, the conversion of flour into analog rice led to decreased levels of carbohydrates, anthocyanins, β-carotene, and antioxidant activity, whereas fat and protein levels increased after transfor-mation into analog rice. The processing stages that significantly contributed to these changes in chemical components included drying, formulation, and extrusion.

Optimizing Nitrate and Tryptone to Enhance Growth and Triacylglycerol Accumulation in Phaeodactylum tricornutum.

Phaeodactylum tricornutum, a unicellular diatom, is considered a potential feedstock for the production of biofuel and a promising producer for high-value products eicosapentaenoic acid and fucoxanthin. However, a high-efficient cultivating strategy to achieve commercial production of triacylglycerol (TAG) from the diatom is an urgent demand. In this study, we optimized the content and ratio of nitrate and tryptone in the medium to enhance biomass and TAG accumulation simultaneously. Growth with tryptone as the sole nitrogen gave rise to the lowest cell density but the highest TAG content in P. tricornutum relative to nitrate, nitrite, ammonium or urea cultures. In 500 μM NaNO3 cultures, the growth of P. tricornutum increased with the increasing concentration (from 294 to 7056 μM nitrogen) of supplemented tryptone, however supplementation of high tryptone (≥882 μM nitrogen) decreased the neutral lipid content. Elevating nitrogen concentration from 294 to 882 μM via tryptone addition in 250 μM nitrate culture increased cell densities from day 6 to 10 and neutral lipid content on day 10. In particular, supplementing 588 μM nitrogen of tryptone in the 250 μM nitrate culture gave rise to the highest neutral lipid content on days 8 and 10 (increased by 109% and 62% relative to 500 μM nitrate-sole) with a comparable growth to that in 500 μM nitratesole culture from day 2 to 8. In conclusion, we optimized nitrate/tryptone ratio and found that a suitable tryptone addition to a relatively low nitrate culture was favourable to the biomass and TAG accumulation simultaneously in P. tricornutum.

Simulation analysis of gas-solid two-phase flow and reaction in a novel catalytic cracking reactor

A gas-solid two-phase flow reaction model was developed to evaluate the performance of a novel catalytic cracking reactor in the residue-to-chemicals (RTC) process. Coupled TFM, EMMS drag, and 12-lump kinetic models were employed to simulate the flow reaction process. The reaction temperature and product yields at the reactor exit aligned well with real industrial RTC reactor test results, indicating the reliability and effectiveness of the coupling model. Catalyst particles formed an internal circulation structure in the reactor, increasing the instantaneous catalyst-to-oil ratio. The reactor exhibited low axial and radial temperature gradients with higher reaction temperatures, accelerating the catalytic cracking rate and enhancing the selectivity for high-value products. The effects of the catalyst-to-oil ratio, catalyst inlet temperature, and feedstock mass flow rate on the flow reaction process were optimized. Results showed that both the catalyst-to-oil ratio and catalyst inlet temperature influenced the overall catalyst velocity distribution. Within the limit range, increasing the catalyst-to-oil ratio increased feedstock conversion, gasoline, LPG, dry gas, and coke yields, but decreased diesel yield. Conversely, increasing the feedstock mass flow rate showed opposite trends. Different trends in product yields were observed with varying inlet catalyst temperatures, with optimal product distribution at 973.15 K.