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Production of Amino Acids by Fermentation
Published in Nduka Okafor, Benedict C. Okeke, Modern Industrial Microbiology and Biotechnology, 2017
Nduka Okafor, Benedict C. Okeke
After wild type strains of C. glutamicum and of other bacteria were found to accumulate glutamic acid, efforts to find in nature bacteria able to yield high amounts of other amino acids failed. The reason for this is that microorganisms avoid over-production of amino acids, producing only the quantity they require. To induce the organism to overproduce, regulatory mechanisms must be disorganized as discussed in Chapter 6. Two major means of regulating amino acid synthesis are feedback inhibition and repression. Auxotrophic mutants and regulatory mutants are two means by which the organisms’ tendency not to overproduce can be disorganized. In order to overproduce an amino acid which is an intermediate in a synthetic pathway, a mutant auxotroph is produced whose pathway in the synthesis is blocked. When this mutant is cultivated, limiting nutrient feedback and/or repression would have been removed and an overproduction of the amino acid will occur. The mutants used for the production of amino acids other than glutamic acid are produced from L-glutamic acid producing bacteria. These bacteria assimilate carbon efficiently and do not degrade the amino acid they excrete.
Catalytic Asymmetric Hydrogenation of α-Acetamidocinnamic Acids
Published in Dale W. Blackburn, Catalysis of Organic Reactions, 2020
Juan G. Andrade, Guenter Prescher, Adolf Schaefer, Ulrich Nagel
A major drawback of any available standard chemical method used for amino acid synthesis is the fact that a racemic mixture of the desired amino acids is obtained. Considering the fact that in most cases only one of the enantiomers is biologically active and therefore the important one, this can be a major obstacle to be resolved. A classical approach for overcoming this problem is shown in Fig. 1.
Electro-galvanic alkalization and treatment of rainwater to obtain drinking water.
Published in Environmental Technology, 2023
Cristina Morales-Figueroa, Ivonne Linares-Hernández, Verónica Martínez-Miranda, Elia Alejandra Teutli-Sequeira, Luis Antonio Castillo-Suárez, Laura Garduño-Pineda
Mg is one of the most abundant micronutrients in the human body. It is a cofactor in more than 300 reactions related to energy metabolism (for instance, in ATP1 molecule synthesis). Moreover, it is involved in the transport of nutrients (e.g., calcium and potassium) across cell membranes as well as in amino acid synthesis. Therefore, a sufficient Mg intake (40–170 mg/day for children and 250–360 mg/day for adults) can help prevent the onset of degenerative diseases (such as osteoporosis and diabetes), improve blood circulation, and prevent neuronal diseases (Maraver et al., 2015; Soriano-pérez et al., 2022; Zhao et al., 2022). Furthermore, ions yielded by the supporting electrolyte, such as , would produce hydrating water with a high energy level (Capozzi et al., 2020; Kuang et al., 2021).
Plant pharmacology: Insights into in-planta kinetic and dynamic processes of xenobiotics
Published in Critical Reviews in Environmental Science and Technology, 2022
Tomer Malchi, Sara Eyal, Henryk Czosnek, Moshe Shenker, Benny Chefetz
Herbicides, whose mechanisms of action include inhibiting photosynthesis, mimicking plant growth regulators, and blocking amino acid synthesis, among others, are dependent on the availability of adequate concentrations at the site of action. For example, triazine herbicides binds to the quinone-binding protein D1 of the plant photosystem II complex, thereby blocking photosynthetic electron transport by displacing plastoquinone from a specific binding site on the D1 protein (Duke, 1990). The desired action of triazine is dependent on ADMA processes, which result in accumulation of the required concentration at the site of action, the chloroplasts. Exposure to low concentrations of triazine has been shown to have non-photosystem II complex interactions which impact root development and molecular signaling networks, as well as hormone response that involves processes regulated by energy, stress, abscisic acid and cytokinin (Alberto et al., 2018). The exposure of plants to low concentrations of non-target herbicides affects plant growth and timing, influencing the plant-insect relationships and ecosystem interactions (Bohnenblust et al., 2016; Russo et al., 2020).
In situ grown rare earth lanthanum on carbon nanofibre for interfacial reinforcement in Zn implants
Published in Virtual and Physical Prototyping, 2022
Mingli Yang, Yang Shuai, Youwen Yang, Da Zeng, Shuping Peng, Zongjun Tian, Cijun Shuai
Zn has been a promising metal material for orthopaedic application in recent decades (Yang et al. 2021; Tong et al. 2020; Yang et al. 2020). Compared with the other two biodegradable metals (iron and magnesium), Zn exhibits excellent degradation behaviour, since its intrinsic standard electrode potential is −0.76 V, which is between iron (−0.45 V) and magnesium (−2.37 V) (Zhou and O'keefe 1997; Andresen and Duquette 1980; Sathyanarayana and Munichandraiah 1981). Meanwhile, no significant gas is released during service compared with magnesium, avoiding the formation of inflammation (Wang et al. 2021). As a necessary trace element, Zn plays an extremely important role in human growth and development, including amino acid synthesis, multiple enzyme activation and immune regulation (Katarivas Levy, Goldman, and Aghion 2017). Furthermore, the released Zn ions can promote the potential cellular signalling pathway of tissue regeneration around implants, thus inducing new bone formation (Shearier et al. 2016; Zan et al. 2022). Despite these advantages, the application of Zn as a hard bone tissue repair material is still limited due to its poor mechanical strength (Zhu et al. 2019).