Hasil untuk "Chemical industries"

U. Biermann, U. Bornscheuer, M. Meier et al.

T. Ren, M. Patel, K. Blok

S. Frokjaer, D. Otzen

K. Jähnisch, V. Hessel, H. Löwe et al.

P. Vandevivere, R. Bianchi, W. Verstraete

M. Aider

K. Komnitsas, D. Zaharaki

Duane T. Johnson, Katherine A. Taconi

Chaofeng Zhang, Feng Wang

In recent decades, research on lignin depolymerization and its downstream product transformation has drawn an enormous amount of attention from academia to industry worldwide, aiming at harvesting aromatic compounds from this abundant and renewable biomass resource. Although the lignin conversion can be traced back to the 1930s and various noncatalytic and catalytic methods have been explored to depolymerize lignin via direct lignin conversion research or lignin models conversion studies, the complexity of the lignin structure, various linkages, the high stability of lignin bonds, and the diverse fragments condensation process make lignin depolymerization to monomers a highly challenging task. For the potential practical utilization of lignin, compared with lignin conversion to liquid fuel with extra H2 consumption, maintaining the aromatic structure and preparing high-value aromatic chemicals from renewable lignin is more profitable. Therefore, lignin depolymerization to easy-to-handle aromatic monomers with acceptable conversion and selectivity is of great importance. In this article, we present our recent studies on lignin's catalytic conversion to aromatic chemicals. First, we introduce our research on protolignin depolymerization via a fragmentation-hydrogenolysis process in alcohol solvents. Then, focusing on the catalytic cleavage of lignin C-C and C-O bonds, we shed light on a recapitulative adjacent functional group modification (AFGM) strategy for the conversion of lignin models. AFGM strategy begins with the adjacent functional group modification of the target C-C or C-O bond to directly decrease the bond dissociation enthalpy (BDE) of targeted bonds or generate new substrate sites to introduce the cleavage reagent for further conversion. Subsequently, on the basis of these two concepts from AFGM, we summarize our strategies on lignin depolymerization, which highlight the effects of lignin structure, catalyst character, and reaction conditions on the efficiency of strategies. In short, the key point for lignin depolymerization to aromatics is promoting the lignin conversion and restraining the condensation. Compared with the complex research on direct lignin conversion, this bottom-up research approach, beginning with lignin model research, can make the conversion mechanism study clear and provide potential methods for the protolignin/technical lignin conversion. In addition, one of our perspectives for lignin utilization is that the products from lignin conversion can be used as monomers for artificial polymerization, such as the simple phenol (PhOH) and other potential acid compounds, or that lignin derivative molecules can be used to synthesize high-value synthetic building blocks.

S. Ou, K. Kwok

G. Filonenko, Robbert van Putten, E. Hensen et al.

Catalytic hydrogenation and dehydrogenation reactions form the core of the modern chemical industry. This vast class of reactions is found in any part of chemical synthesis starting from the milligram-scale exploratory organic chemistry to the multi-ton base chemicals production. Noble metal catalysis has long been the key driving force in enabling these transformations with carbonyl substrates and their nitrogen-containing counterparts. This review is aimed at introducing the reader to the remarkable progress made in the last three years in the development of base metal catalysts for hydrogenations and dehydrogenative transformations.

Zheng Liu, Ting Gao, Shaoheng Bao et al.

<i>Neo-allo</i>-ocimene is a monoterpene which could be applied in pesticides, fragrances, and sustainable polymers. In this study, we mined a terpene synthase, AgTPS40, from the transcriptome of celery leaf tissues. Through sequence and phylogenetic analysis, AgTPS40 was characterized as a monoterpene synthase. The <i>AgTPS40</i> gene was introduced into a heterologous mevalonate pathway hosted in <i>Escherichia coli</i> to enable terpene production. Gas chromatography–mass spectrometry analysis confirmed that AgTPS40 catalyzes the formation of <i>neo-allo</i>-ocimene, marking the first reported identification of a <i>neo-allo</i>-ocimene synthase. Subsequently, we optimized the fermentation conditions and achieved a yield of 933.35 mg/L in a 1 L shake flask, which represents the highest reported titer of <i>neo-allo</i>-ocimene to date. These results reveal the molecular basis of <i>neo-allo</i>-ocimene synthesis in celery and provide a sustainable way to obtain this compound.

Noura E. Mahmoud, Reda M. Abdelhameed

Abstract Micronutrient deficiencies in soil can significantly hinder plant growth and reduce crop production; therefore, foliar application of these micronutrients to plants becomes effective. Although metal-organic frameworks (MOFs) are frequently used in gas storage, adsorption, and catalysis, their application in agriculture has been rather uncommon. The purpose of this study was to ascertain how the growth parameters of faba bean (Vicia faba L.) plants were affected by nickel (Ni2+), chromium (Cr3+), cobalt (Co2+), and copper (Cu2+) MOFs. Using spectroscopic analysis, frameworks for Ni-BTC, Cr-BTC, Co-BTC, and Cu-BTC were described. These frameworks’ effects on the faba plants’ physiological stress indices, leaf chlorophyll and phenolic contents, fresh and dry weight of the roots and shoots, and shoot and root length were measured. According to our findings, Cu-BTC improved plant growth and development, resulting in a 37.79% increase in fresh shoot weight and a 40.42% increase in dry weight. Additionally, there was a 62.96% rise in the fresh weight of roots and a 75.0% increase in the dry weight of roots. The diameter of the stem was increased by 31.5% and the leaf surface area increased by 46.22%. There was an improvement in the amount of pigments, with carotenoids growing 1.91 times, chlorophyll a an increasing 1.59 times, and chlorophyll b increasing 2.07 times. On the other hand, Cr-BTC showed a negative impact on the growth of the plant; malondialdehyde (MDA) and H2O2 levels were raised by 4.54% and 14.21%, respectively, compared to the control. Although micronutrients are essential for plant growth and development, plants need them in small quantities. MOFs will deliver these micronutrients to plants in a controlled and efficient manner. MOFs can enhance nutrient uptake and reduce environmental impact by minimizing nutrient leaching and pollution.

D. Huccetogullari, Z. Luo, S. Lee

Metabolic engineering has been enabling development of high performance microbial strains for the efficient production of natural and non-natural compounds from renewable non-food biomass. Even though microbial production of various chemicals has successfully been conducted and commercialized, there are still numerous chemicals and materials that await their efficient bio-based production. Aromatic chemicals, which are typically derived from benzene, toluene and xylene in petroleum industry, have been used in large amounts in various industries. Over the last three decades, many metabolically engineered microorganisms have been developed for the bio-based production of aromatic chemicals, many of which are derived from aromatic amino acid pathways. This review highlights the latest metabolic engineering strategies and tools applied to the biosynthesis of aromatic chemicals, many derived from shikimate and aromatic amino acids, including l-phenylalanine, l-tyrosine and l-tryptophan. It is expected that more and more engineered microorganisms capable of efficiently producing aromatic chemicals will be developed toward their industrial-scale production from renewable biomass.

Aleksandra Katanski, Vesna Vučurović, Damjan Vučurović et al.

The present work highlights the advances of integrated starch and bioethanol production as an attractive industrial solution for complex wheat exploitation to value-added products focusing on increased profitability. Bioethanol is conventionally produced by dry-milling wheat grain and fermenting sugars obtained by the hydrolysis of starch, while unused nonfermentable kernel compounds remain in stillage as effluents. On the other hand, the wet-milling of wheat flour enables complex wheat processing for the simultaneous production of starch, gluten, and fiber. The intermediates of industrial wheat starch production are A-starch milk, containing mainly large starch granules (diameter > 10 μm), and B-starch milk, containing mainly small starch granules (diameter < 10 μm). The present study investigates different starch hydrolysis procedures using commercial amylase for bioethanol production from A-starch and B-starch milk by batch fermentation using distillers’ yeast <i>Saccharomyces cerevisiae</i> Thermosacc^®. Cold hydrolysis with simultaneous liquefaction and saccharification at 65 °C, a pH of 4.5, and a duration of 60 min was the most efficient and energy-saving pretreatment reaching a high conversion rate of starch to ethanol of 93% for both of the investigated substrates. A process design and cost model of bioethanol production from A-starch and B-starch milk was developed using the SuperPro Designer^® v.11 (Intelligen Inc., Scotch Plains, NJ, USA) software.

João Mota, Alice Vilela

This review critically examines the multifaceted role of acetic acid bacteria (AAB) in the intricate production process of port wine vinegar, particularly in its transformative process from port wine. With the emergence of port wine vinegar as a distinctive agricultural product in 2018, producers have been faced with a diverse array of challenges, ranging from reducing the high alcohol content to preserving the inherent sweetness. Through an exhaustive exploration of acetic fermentation processes and the indispensable role of AAB, this review meticulously elucidates the complex biochemistry underlying vinegar formation, delving into the nuanced interactions between microbial activity and chemical composition. Furthermore, this review underscores the importance of sensory characteristics and consumer perception derived from vinegar production, providing invaluable insights into these fermented products’ sensory profiles and marketability. In summary, this study offers valuable insights into the evolution of port wine into vinegar, highlighting its significance in agricultural and culinary contexts.

Shumaila Kiran, Hasan B. Albargi, Gulnaz Afzal et al.

Abstract A variety of industries employ synthetic azo dyes. However, the biosphere is being damaged by the unused/leftover azo dyes, which pose a danger to all living things. Therefore, treating them to shield the environment from the potential harm of azo dyes is crucial. Bio-sorption is a cheap and effective mode for eliminating toxic dyes in the environment. The current work focused on synthesizing magnesium oxide (MgO) nanoparticles using an aqueous leaf extract of neem (Azadirachta indica). The XRD and SEM analyses of MgO nanoparticles indicated the crystalline nature of MgO nanoparticles with a cubic structure, and the size was around 90–100 nm. FTIR analysis showed the presence of a stretching frequency peak at 550 cm−1, confirming the Mg–O bond. The surface analysis revealed the cluster form of the synthesized nanoparticles. The UV–visible absorption peak for MgO nanoparticles was found at 294 nm and band gap of 4.52 eV. In order to eliminate the Reactive Red 195 dye, MgO nanoparticles were used. At pH 4, 40 °C, 0.02% dye concentration, and 0.003 g/L catalyst amount, the highest degree of decolorization (91%) was seen. Decreased total organic carbon (TOC) and the chemical oxygen demand (COD) percent were 84.33% and 81.3%, respectively. The proposed mechanism of target dye degradation was also investigated. MgO NPs were found to be effective in their catalytic behavior toward the degradation of Reactive Red 195 dye up to five cycles with almost no change in their catalytic activity.

Aleksandra A. Jovanović, Bojana Balanč, Mina Volić et al.

In the present study, rosehip (<i>Rosa canina</i> L.) extract was successfully encapsulated in phospholipid liposomes using a single-step procedure named the proliposome method. Part of the obtained liposomes was subjected to UV irradiation and non-treated (native) and UV-irradiated liposomes were further characterized in terms of encapsulation efficiency, chemical composition (HPLC analysis), antioxidant capacity, particle size, PDI, zeta potential, conductivity, mobility, and antioxidant capacity. Raman spectroscopy as well as DSC analysis were applied to evaluate the influence of UV irradiation on the physicochemical properties of liposomes. The encapsulation efficiency of extract-loaded liposomes was higher than 90%; the average size was 251.5 nm; the zeta potential was −22.4 mV; and the conductivity was found to be 0.007 mS/cm. UV irradiation did not cause a change in the mentioned parameters. In addition, irradiation did not affect the antioxidant potential of the liposome–extract system. Raman spectroscopy indicated that the extract was completely covered by the lipid membrane during liposome entrapment, and the peroxidation process was minimized by the presence of rosehip extract in liposomes. These results may guide the potential application of rosehip extract-loaded liposomes in the food, pharmaceutical, or cosmetic industries, particularly when liposomal sterilization is needed.

Chengzhe Zhou, Caiyun Tian, Chen Zhu et al.

Non-coding RNAs (ncRNAs) are functional transcripts with minimal or no protein-coding capacity that comprise a large portion of the plant transcriptome. Among them, the microRNAs (miRNAs), linear long ncRNAs (lncRNAs), and circular long ncRNAs (circRNAs) have been widely proven to play essential regulatory roles in the biosynthesis of secondary metabolites (SMs) by modulating the expression of key synthesis-related genes in plants. Tea boasts numerous characteristic SMs, such as catechins, theanine, caffeine, volatile compounds, etc., which have distinguished health properties and largely determine the pleasant flavor quality. Thus, understanding how the tea plant produces these specialized metabolites is of great research interest. With the innovation and progress of biotechnologies in recent years, significant progress has been made in research on the regulation mechanism of SMs in tea plants at the DNA, mRNA, protein and metabolite levels. The release of the genome sequences of tea plants paves a path for precisely exploring ncRNAs and their functions in tea, and their huge potential for the biosynthesis regulation of SMs has gradually received attention. We herein summarize recent progress on miRNAs, lncRNAs, and circRNAs in tea plants and discuss their regulatory roles in the accumulation of SMs to enlighten the development of novel agronomic tools to enhance the quality of tea.

Yan Xing, Xichuan Lu, Yi Li et al.

Abstract Semiconductor heterojunction plays a pivotal role in photocatalysis. However, the construction of a heterojunction with a fine microstructure usually requires complex synthetic procedures. Herein, a pH-adjusted one-step method was employed to controllably synthesize Ag4V2O7/Ag3VO4 heterojunction with a well-tuned 0D/1D hierarchical structure for the first time. It is noteworthy that the ordered stacking of vanadium oxide tetrahedron $$(\rm{VO}_3^-)$$ ( V O 3 − ) guided by the pH value wisely realizes the in-situ growth of Ag4V2O7 nanoparticles on the surface of Ag3VO4 nanorods. Furthermore, comprehensive characterization and calculation decipher the electronic structures of Ag4V2O7 and Ag3VO4 and the formation of Z-scheme heterojunction, benefiting the visible light harvesting and carrier utilization. Such a new Ag4V2O7/Ag3VO4 heterojunction exhibits remarkable photocatalytic activity and excellent stability. Complete degradation of Rhodamine B (RhB) can be achieved in 10 min by the Ag4V2O7/Ag3VO4 heterojunction under visible light irradiation, demonstrating an outstanding reaction rate of 0.35 min−1 that is up to 84-fold higher than those of other silver vanadates. More importantly, this integration of synthesis technology and heterojunction design, based on the intrinsic crystal and electronic structures, could be inspiring for developing novel heterostructured materials with advanced performance.