Hasil untuk "Chemical industries"

K. Kadirvelu, K. Thamaraiselvi, C. Namasivayam

Shichun Xu, Zhengxia He, R. Long

A. Singh, J. V. Van Hamme, O. Ward

P. Bautista, Á. F. Mohedano, J. Casas et al.

R. Morris

S. C. Shit, Pathik Shah

T. Friščić, I. Halász, Patrick J. Beldon et al.

Luis Carlos Mata-Gómez, J. Montañez, Alejandro Méndez-Zavala et al.

Nowadays, carotenoids are valuable molecules in different industries such as chemical, pharmaceutical, poultry, food and cosmetics. These pigments not only can act as vitamin A precursors, but also they have coloring and antioxidant properties, which have attracted the attention of the industries and researchers. The carotenoid production through chemical synthesis or extraction from plants is limited by low yields that results in high production costs. This leads to research of microbial production of carotenoids, as an alternative that has shown better yields than other aforementioned. In addition, the microbial production of carotenoids could be a better option about costs, looking for alternatives like the use of low-cost substrates as agro-industrials wastes. Yeasts have demonstrated to be carotenoid producer showing an important growing capacity in several agro-industrial wastes producing high levels of carotenoids. Agro-industrial wastes provide carbon and nitrogen source necessary, and others elements to carry out the microbial metabolism diminishing the production costs and avoiding pollution from these agro-industrial wastes to the environmental. Herein, we discuss the general and applied concepts regarding yeasts carotenoid production and the factors influencing carotenogenesis using agro-industrial wastes as low-cost substrates.

Teshale Adane, Amare T. Adugna, Esayas Alemayehu

Dyes and other chemicals laden wastewater is a main environmental concern for increasing the textile industries in many parts of the world. Textile industries consume different kinds of manmade dyes or other chemicals and release huge extents of highly polluted water into the environment. &is excessive dye laden wastewater has great impacts on photosynthetic activity in aquatic plants and animals, for example, fish. It may also affect human health due to the presence of components like heavy metals and chlorine in manmade dyes. &us, wastewater effluent from textile industries must be treated before discharge into the water body. Treatment technologies observed in this review paper include biological treatment methods (fungi, algae, bacteria, and microbial fuel cells), chemical treatment methods (photocatalytic oxidation, ozone, and Fenton’s process), and physicochemical treatment methods (adsorption, ion exchange, coagulation, and filtration).&is review also includes the hybrid treatment methods and their cost per m of treated wastewater analysis. &ere are alternative wastewater treatments systems at different steps of effluent generated from the textile operational unit recommend in this review work.

Y. Jani, W. Hogland

J. Vymazal

M. Volk, V. Tran, Shih-I Tan et al.

Metabolic engineering aims to improve the production of economically valuable molecules through the genetic manipulation of microbial metabolism. While the discipline is a little over 30 years old, advancements in metabolic engineering have given way to industrial-level molecule production benefitting multiple industries such as chemical, agriculture, food, pharmaceutical, and energy industries. This review describes the design, build, test, and learn steps necessary for leading a successful metabolic engineering campaign. Moreover, we highlight major applications of metabolic engineering, including synthesizing chemicals and fuels, broadening substrate utilization, and improving host robustness with a focus on specific case studies. Finally, we conclude with a discussion on perspectives and future challenges related to metabolic engineering.

Pattarawan Intasian, K. Prakinee, A. Phintha et al.

Since the industrial revolution, the rapid growth and development of global industries have depended largely upon the utilization of coal-derived chemicals, and more recently, the utilization of petroleum-based chemicals. These developments have followed a linear economy model (produce, consume, and dispose). As the world is facing a serious threat from the climate change crisis, a more sustainable solution for manufacturing, i.e., circular economy in which waste from the same or different industries can be used as feedstocks or resources for production offers an attractive industrial/business model. In nature, biological systems, i.e., microorganisms routinely use their enzymes and metabolic pathways to convert organic and inorganic wastes to synthesize biochemicals and energy required for their growth. Therefore, an understanding of how selected enzymes convert biobased feedstocks into special (bio)chemicals serves as an important basis from which to build on for applications in biocatalysis, metabolic engineering, and synthetic biology to enable biobased processes that are greener and cleaner for the environment. This review article highlights the current state of knowledge regarding the enzymatic reactions used in converting biobased wastes (lignocellulosic biomass, sugar, phenolic acid, triglyceride, fatty acid, and glycerol) and greenhouse gases (CO2 and CH4) into value-added products and discusses the current progress made in their metabolic engineering. The commercial aspects and life cycle assessment of products from enzymatic and metabolic engineering are also discussed. Continued development in the field of metabolic engineering would offer diversified solutions which are sustainable and renewable for manufacturing valuable chemicals.

Muhong Li, Shanyong Chen, Qike Jiang et al.

The production of functionalized anilines by chemoselective hydrogenation of nitroarenes occupies an important position in the chemical industries. Recently, cobalt and nitrogen codoped carbon (Co–...

Y. Wee, Jin-nam Kim, H. Ryu

Summary Lactic acid is widely used in the food, cosmetic, pharmaceutical, and chemical industries and has received increased attention for use as a monomer for the production of biodegradable poly(lactic acid). It can be produced by either biotechnological fermentation or chemical synthesis, but the former route has received considerable interest recently, due to environmental concerns and the limited nature of petrochemical feedstocks. There have been various attempts to produce lactic acid efficiently from inexpensive raw materials. We present a review of lactic acid-producing microorganisms, raw materials for lactic acid production, fermentation approaches for lactic acid production, and various applications of lactic acid, with a particular focus on recent investigations. In addition, the future potentials and economic impacts of lactic acid are discussed.

K. Rajurkar, D. Zhu, J. McGeough et al.

Qingyi Kong, Rao Zhang, Lei Chen et al.

Phase decomposition can effectively enhance the mechanical properties of carbide ceramics and can overcome the difficulty of enhancing the mechanical properties of single-phase multicomponent carbide ceramics. In this work, a series of nonstoichiometric (TiZrVNb)Cx ceramics were prepared by spark plasma sintering (SPS) at different temperatures. The effects of the carbon content on the phase composition, microstructure evolution, and mechanical properties were investigated in detail. Phase decomposition occurred with decreasing carbon content. Two different solid solutions of (Ti,V)-rich and Zr-rich phases formed from the decomposition of equimolar single-phase solid solutions, namely, the Zr-poor phase and Zr-rich phase, respectively. The distribution of Nb element is relatively uniform. The semicoherent interfaces between the Zr-poor phase and the Zr-rich phase can harden and strengthen effectively under the synergistic effect of grain refinement. Ceramics with phase decomposition structures have apparent advantages compared to single-phase high-entropy carbides. This work provides an important train of thought for the microstructure tailoring and properties optimization of multi-component carbide ceramics.

Johnson N. Naat, Yantus Neolaka, Yosep Lawa et al.

This study aims to examine histamine adsorption using Takari natural sand-based SiO2@BSA as the silica source. Silica was extracted using the hydrothermal and coprecipitation methods and then modified into SiO2@BSA adsorbent using the ultrasonication method. After that, the adsorbent was used to adsorb histamine. The results showed that the mass ratio of SiO2 and BSA to the histamine adsorption was 1:0.02 (qe=11.39 mg/g), with optimum adsorption pH of 5 (qe= 12.33 mg/g) and a contact time of 60 minutes (qe=12.36 mg/g). The percentage of histamine removal was 96%. The kinetic model was pseudo-second order type 1 with an adsorption rate constant of 6.3x103 g/mg, while the isotherm model was Langmuir with R2=0.997; qe=18 mg/g. Thermodynamic parameters indicated that the adsorption process was exothermic with a high degree of randomness, and the histamine adsorption by silica-based SiO2@BSA adsorbent from natural sand occurred chemically.

Hiba Ismaeel, Talib Albayati, Hayder Dhahad et al.

In this study, mesoporous silica nanoparticles (MSNs) with a hexagonal structure and large surface area were synthesized via a sol-gel method. The properties of the synthesized MCM-41 catalyst were characterized using BET, EDX, XRD, and FTIR analyses. The results showed that the MCM-41 had a high surface area of 966 m2/g and large pore volume of about 0.91 cm3/g. Sunflower oil was converted to biodiesel in a batch reactor at different temperatures (40, 50, 60 °C), methanol-to-oil molar ratios (6:1, 9:1, 12:1), catalyst loadings (0.7, 0.9, 1.25 wt%), and reaction times (up to 80 min) using the prepared catalyst under atmospheric pressure. The biodiesel yield was found to reduce when the reaction time exceeded 1 hour despite maintaining the catalyst. The maximum biodiesel yield of 45% was obtained under optimal conditions of a 9:1 methanol-to-oil ratio, 1.25 wt% catalyst loading, 60 °C temperature, and 60 min reaction time. GC-MS analysis characterized the biodiesel composition and properties. The synthesized biodiesel showed improved properties compared to conventional fuels, with linoleic acid methyl ester (C17H34O2, 25.93%) as the main component. The MCM-41 catalyst exhibited remarkable catalytic activity and could be recovered, regenerated, and reused, reducing reaction costs. This makes it a potential alternative to homogeneous catalysts that complicate product separation.

M. García-Galán, F.J. Martínez-Vázquez, N. Rebollo-Muñoz et al.

A novel method for obtaining ceramic (tricalcium phosphate, TCP) fibres with a small diameter (below 0.1 mm) is proposed and its potential use in the 3D printing of scaffolds for biomedical applications is explored. An ink consisting of a high solid content (40 vol%) ceramic slurry in a photocurable resin was prepared and extruded using near-field electrospinning. The influence of the electric potential, flow rate, and distance between tip and collector on the fabrication process in static mode were studied and the role played by unidirectional motion of the collector was also analyzed. A one order of magnitude reduction in the diameter of the jet to around 30 μm is demonstrated under static conditions, which increased to around 100 μm when collector was displaced. Continuous fibres were deposited but the slurry spread over the collector. The method was implemented on a DIW system, using in-flight UV light curing to prevent the spreading of the ink upon deposition. The feasibility of the strategy was demonstrated, although challenges remain for the optimization and control of the fabrication process. Nevertheless, these preliminary results suggest this could be a promising alternative to produce 3D ceramic scaffolds for biomedical applications with improved spatial resolution. Resumen: Se propone un nuevo método para la obtención de fibras cerámicas (fosfato tricálcico, TCP) de pequeño diámetro (menos de 0.1 mm) y se explora su potencial uso en la impresión 3D de andamiajes para aplicaciones biomédicas. Suspensiones cerámicas de alto contenido sólido (40 vol%) en una resina fotocurable fueron extruidas mediante electrohilado de campo cercano, analizando la influencia del potencial eléctrico, el caudal y la distancia entre la punta y el colector y el movimiento de este en el diámetro de la fibra. Se demuestra una reducción de un orden de magnitud en el diámetro del chorro hasta ∼30 μm en estático y hasta ∼100 μm con el colector en movimiento. Se depositaron fibras continuas, pero se observó esparcimiento de la suspensión sobre el colector. El método se implementó en un sistema de moldeo robotizado, utilizando curado en vuelo por luz ultravioleta para evitar el esparcimiento de la tinta tras la deposición. Aunque la viabilidad de la estrategia queda demostrada, siguen existiendo retos para la optimización y control del proceso de fabricación. No obstante, estos resultados preliminares indican que esta técnica podría ser una alternativa prometedora para producir andamios cerámicos 3D para aplicaciones biomédicas con una resolución espacial mejorada.