Hasil untuk "Chemical industries"

L. Tietze, U. Beifuss

A. Banerjee, Rohit Sharma, Y. Chisti et al.

A. de Silva, S. Uchiyama

T. Saha

Kesavan Hema, Ramachandran Karnan, Bakthavatchalam Senthil et al.

Hibiscus rosa-sinensis L. flower has been known to contain polyphenolic compounds, so the current study focuses on the isolation, identification, characterization, and biological applications of flavonoid compounds from H. rosa-sinensis flower, with an emphasis on antioxidant and antibacterial activities. Flavonoid was extracted from flower extract in ethyl acetate and characterized using chemical tests, TLC, UV, HPLC, FTIR, 1H-NMR, and 13C-NMR. Azaleatin-3,7-di-O-glucoside, a quercetin derivative, was found to effectively scavenge DPPH, ABTS, and Nitric oxide (IC50 = 24.61, 22.38, and 39.79 μg/mL) and antioxidant activity index (AAI) determined to be 1.015, indicating a strong level of antioxidant activity, while PASS prediction revealed the higher antioxidant (Pa = 0.786). Furthermore, Azaleatin-3,7-di-O-glucoside demonstrated greater antibacterial activity against Staphylococcus aureus, a gram-positive bacteria, than against gram-negative bacteria such as Escherichia coli. The study concluded that flavonoid compounds can be used as antibacterial and antioxidant agents, as well as has powerful free-radical scavenging properties, which may be mediated by their phenolic and flavonoid concentrations, and are an excellent source for the medical and pharmaceutical industries and human society.

M. Śmiglak, J. Pringle, Xingmei Lu et al.

As highlighted by the recent ChemComm web themed issue on ionic liquids, this field continues to develop beyond the concept of interesting new solvents for application in the greening of the chemical industry. Here some current research trends in the field will be discussed which show that ionic liquids research is still aimed squarely at solving major societal issues by taking advantage of new fundamental understanding of the nature of these salts in their low temperature liquid state. This article discusses current research trends in applications of ionic liquids to energy, materials, and medicines to provide some insight into the directions, motivations, challenges, and successes being achieved with ionic liquids today.

C. Gerday, M. Aittaleb, Mostafa Bentahir et al.

Hui Zhang, Hong Wang, Xun Zhu et al.

E. Abbasi, M. Milani, Sedigheh Fekri Aval et al.

Adedoyin Titi Amos, Damilola Uthman Kareem, Tolulope Modupe Adeleye et al.

This study evaluates the effects of solid-state fermentation inoculated with <i>Aspergillus</i> spp. on the nutritional profile of selected agro-industrial by-products (AIBPs: cowpea shell, groundnut shell, soybean hull, and maize shaft). These AIBPs were assessed as potential feedstuffs in weaner rabbit diets, which often exhibit digestive disorders when introduced to highly lignified feed ingredients. The AIBPs were milled to a particle size of 2 mm, sterilized, and subjected to fermentation with <i>Aspergillus</i> spp. under microaerophilic conditions at 28 ± 2 °C for 10 days. Samples (four replicates per treatment) were analyzed for chemical constituents (mineral and proximate composition, anti-nutritional factors, and fibre fractions) before and after fermentation. Digestible energy and digestibility coefficient of gross energy were calculated. Data were subjected to two-way analysis of variance (ANOVA). There was an increase (<i>p</i> < 0.05) in mineral profile, proximate composition, digestible energy, digestibility coefficient of gross energy, and dry matter, with a reduction (<i>p</i> < 0.05) in crude fibre, fibre fractions, and anti-nutritional factors. It was concluded that fermentation with <i>Aspergillus</i> spp. improved the nutritional value of the selected agro-industrial by-products. Therefore, fermented materials possess a better nutritional profile to be used in feeding programs for weaner rabbits. This will ensure sustainable animal production and add value to agricultural waste, which would otherwise constitute an environmental nuisance.

A. Perrin, O. Musa, J. Steed

This review aims to introduce the chemistry of low dosage inhibitors of clathrate hydrate formation within the context of their role in the oil and gas industry. The review covers both kinetic hydrate inhibitors and anti-agglomerants from the point of view of structure-function relationships, focussing on recent refinements in mechanistic understanding and chemical design, and the consequently evolving and increasingly fine-tuned properties of these fascinating compounds.

T. T.T. Nguyen, H. B. Bui

Kaolin (mainly composed of kaolinite, whose chemical formula is Al2Si2O5(OH)4), serves as a versatile raw material widely used in various industries including production of ceramics, paper, paints, cosmetics, pneumatics, building materials, and hazardous waste storage. In the northern part of Vietnam, due to favorable geological conditions, there are diverse deposits of high quality kaolin of different origin and scale. Decades of research indicate the diversity of kaolin sources in the region, with special attention paid to hydrothermally altered and exchange types of kaolin, the formation of which is associated with complex processes of weathering, hydrothermal alteration and reprecipitation. The aim of this study was to characterize three different types of kaolin derived from different sources in Northern Vietnam (from weathered pegmatites, weathered felsic effusives, and hydrothermal-metasomatic altered rocks). The main focus was to analyze the thermal behavior of these samples during calcination in the temperature range from 300 °C to 1,100 °C. The comprehensive characterization was performed by X-ray diffraction (XRD), FT-IR spectroscopy (FT-IR), thermal analysis (thermogravimetry / differential thermogravimetry (TG / DTG)) and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS). The results showed that kaolinite with particle size less than 2 μm was identified in all samples. Minor amounts of muscovite and montmorillonite are present in some samples, and pyrophyllite is present in a sample from the hydrothermally altered rocks. Kaolinite morphology in all the samples showed typical forms including hexagonal and pseudohexagonal. The main chemical constituents of the samples are SiO2 and Al2O3; in addition to these, K2O + Na2O, TiO2 and iron are present in smaller quantities. Thermal analysis allowed to reveal the formation of metakaolinite phase at temperatures around 494 °C and 507 °C in the two studied samples from weathered rocks, while the pyrophyllite-bearing sample undergoes this transition at a higher temperature of 653.8 °C. The onset of metakaolinization was observed at about 500 °C for the weathered rock samples and about 700 °C for the pyrophyllite-bearing sample. In addition, mullitization leading to the formation of mullite was evident at 1,100 °C. The study findings allow concluding that the studied kaolins can be used in traditional ceramics production.

Xinghua Su, Wenjin Li, Da Chen et al.

The introduction of oxygen vacancies into zirconia is an effective strategy for enhancing its light absorption ability and photocatalytic performance. However, the cost-efficient preparation of oxygen-deficient zirconia (ZrO2−x) remains challenging, which severely limits its broad application. In this study, flash sintering treatment was used to fabricate ZrO2−x bulk in very short time of 90 s. Oxygen vacancies were introduced into ZrO2 bulk through electrochemical reduction reactions. The as-prepared black ZrO2−x exhibited excellent optical absorption capability, a small band gap (2.09 eV for direct and 1.67 eV for indirect), and a reduced conduction band energy, which is ascribed to the generation of oxygen vacancies and reduction of Zr cations. The as-prepared ZrO2−x showed remarkable photocatalytic activity due to excellent solar light absorption and low recombination rate of electron‒hole pairs. Flash sintering treatment provides a cost-efficient approach for rapidly fabricating ZrO2−x bulk materials with high concentrations of oxygen vacancies, which can also be applied to other materials.

A. Fryszkowska, Paul N. Devine

Enzyme catalysis, enabled by advances in protein engineering and directed evolution, is beginning to transform chemical synthesis in the pharmaceutical industry. This review presents recent examples of the creative use of biocatalysis to enable drug discovery and development. We illustrate how increased access to novel biotransformations and the rise of cascade biocatalysis allowed fundamentally new syntheses of novel medicines, representing progress toward more sustainable pharmaceutical manufacturing. Finally, we describe the opportunities and challenges the industry must address to ensure the reduction to practice of biotechnological innovations to develop new therapies in a faster, more economical, and environmentally benign way.

Kiseok Lee, Shawn Ni

M. Post

Viviana K. Rivera Flores, Xingrui Fan, Timothy A. DeMarsh et al.

Previous studies highlighted <i>Brettanomyces claussenii</i> as a versatile yeast that produces ethanol or acetic acid from lactose, or selectively metabolizes glucose while leaving behind galactose, depending on different operational conditions. This flexibility enables the production of galactose-rich bioproducts from liquid dairy residues. The purpose of this study is to: (i) optimize the anaerobic fermentation of milk permeate (MP) by <i>B. claussenii</i> to maximize the yields of galactose and ethanol and minimize leftover glucose, and (ii) combine the optimized process with distillation and drying and characterize its multiple products. Response surface methodology was used for the optimization. Three fermentation parameters were chosen as input factors: temperature (25–35 °C), inoculation level (7.0–8.5 log cfu/mL), and time (4–40 days), with three metabolites as responses: galactose, glucose, and ethanol. The optimal combination of parameters resulted in temperature, 28 °C; inoculation level, 7.6 log cfu/mL; and time, 33 days. Under these conditions, the fermented product was predicted to have 63.6 g/L galactose, 4.0% <i>v</i>/<i>v</i> ethanol, and 0 g/L residual glucose. The optimal parameters were used to run 18 L fermentations followed by distillation and freeze-drying. As a result, four product streams were obtained and characterized for relevant physicochemical and nutritional attributes. Our results show that the partial fermentation of MP by <i>B. claussenii</i> can be the first step to develop lactose-free, low-in-glucose, galactose-rich bioproducts, which improve the value of this residue and broaden its applications in the food supply chain.

Farhana R. Pinu, Lily Stuart, Taylan Topal et al.

Evidence from the literature suggests that different inoculation strategies using either active dry yeast (ADY) or freshly prepared yeast cultures affect wine yeast performance, thus altering biomass and many primary and secondary metabolites produced during fermentation. Here, we investigated how different inoculation methods changed the fermentation behaviour and metabolism of a commercial wine yeast. Using a commercial Sauvignon blanc (SB) grape juice, fermentation was carried out with two different inoculum preparation protocols using <i>Saccharomyces cerevisiae</i> X5: rehydration of commercial ADY and preparation of pre-inoculum in a rich laboratory medium. We also determined the effect of different numbers of yeast cells inoculation (varying from 1 × 10⁶ to 1 × 10¹²) and successive inoculation on fermentation and end-product formation. The yeast inoculation method and number of cells significantly affected the fermentation time. Principal component analysis (PCA) using 60 wine metabolites showed a separation pattern between wines produced from the two inoculation methods. Inoculation methods influenced the production of amino acids and different aroma compounds, including ethyl and acetate esters. Varietal thiols, 3-mercaptohexanol (3MH), and 4-methyl-4-mercaptopentan-2-one (4MMP) in the wines were affected by the inoculation methods and numbers of inoculated cells, while little impact was observed on 3-mercaptohexyl acetate (3MHA) production. Pathway analysis using these quantified metabolites allowed us to identify the most significant pathways, most of which were related to central carbon metabolism, particularly metabolic pathways involving nitrogen and sulphur metabolism. Altogether, these results suggest that inoculation method and number of inoculated cells should be considered in the production of different wine styles.

Candela Ruiz-de-Villa, Jordi Gombau, Montse Poblet et al.

This study investigates the impact of inoculating <i>Torulaspora delbrueckii</i> (Td) strains during the initial phase of carbonic maceration (CM) vinification, aiming to enhance the fermentative process and unique characteristics of CM wines. CM is a winemaking technique where whole bunches (without destemming and crushing) are enclosed in tanks filled with carbon dioxide, inducing intracellular fermentation. This study compares the effects of two Td strains on the MLF performance and sensory characteristics of CM wines using both inoculated and spontaneous MLF strategies. Although general physicochemical parameters remained consistent across conditions, organoleptic attributes showed significant differences due to <i>T. delbrueckii</i> presence. <i>T. delbrueckii</i> introduction during CM resulted in wines with increased anthocyanin content and a particular volatile profile. Isoamyl acetate, a key aroma in CM wines, was notably elevated, especially in the TdP strain. Sensory evaluations also revealed distinctions, with TdV wines displaying more pronounced aromas of red fruit, banana, and grass. Regarding MLF, <i>T. delbrueckii</i> presence notably enhanced performance, particularly in spontaneous MLF cases, accelerating fermentation completion. Inoculating the <i>Oenococcus oeni</i> strain OoVP41 also shortened MLF duration. These findings highlight the potential of Td strains to improve MLF efficiency and sensory attributes in CM wines. Using <i>T. delbrueckii</i> strains strategically enables winemakers to optimize MLF and improve sensory profiles, offering an opportunity to produce higher-quality CM wines.

K. V. Van Geem, V. Galvita, G. Marin

Hydrogen can be produced in electrically heated reactors, reducing CO2 emissions Vast amounts of energy are needed to synthesize the hundreds of millions of tons of chemicals used in everyday life each year. To meet that demand, the chemical industry uses the energy released during fuel combustion, thereby producing a seventh of the anthropogenic emissions of greenhouse gases. Climate change makes it mandatory to replace fossil fuels in chemical production processes and reduce their climate impact (1–3). On page 756 of this issue, Wismann et al. (4) focus on reducing the CO2 emissions created during the production of molecular hydrogen (H2), a key building block for ammonia-derived fertilizers, through steam reforming of methane. This industrial process releases 9 kg of CO2 per kg of H2, a quarter of which comes from fuel combustion.