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Fundamentals of biology and thermodynamics
Published in Mohammad E. Khosroshahi, Applications of Biophotonics and Nanobiomaterials in Biomedical Engineering, 2017
The native conformation of protein has a 3-D structure. Primary structure is the linear sequence of amino acids along the polypeptide backbone. Secondary structure is the folding of certain regions of the protein into helical arrays. tertiary structure is the single polypeptide chain. Quarternary structure is the relative arrangement of polypeptide chains in higher order aggregates. Denaturation is a process in which proteins or nucleic acids lose the quaternary structure, tertiary structure, and secondary structure which is present in their native state, by application of some external stress or compound such as a strong acid or base, a concentrated inorganic salt, an organic solvent (e.g., alcohol or chloroform), radiation, or heat. If proteins in a living cell are denatured, this results in disruption of cell activity, and possibly cell death. Denatured proteins can exhibit a wide range of characteristics, from conformational change and loss of solubility to aggregation due to the exposure of hydrophobic groups. It should be noted that when proteins are coagulated they tend to clump into a semi-soft, solid-like substance. A chemical change has taken place because a new substance is produced.
Energy and resource recovery from sludge
Published in Bhola R. Gurjar, Vinay Kumar Tyagi, Sludge Management, 2017
Bhola R. Gurjar, Vinay Kumar Tyagi
Enzymes assist as biological catalysts; specifically they accelerate chemical reactions without undergoing any net chemical change during the reaction (Tyagi et al., 2009). The recovered enzymes can be useful to enhance the sludge degradation and subsequent biogas generation during the anaerobic digestion (Nabarlatz et al., 2010). There is a potential to recover the various enzymes such as Protease, Glycosidase, Dehydrogenase Catalase, peroxidase, α-amylase, α-glucosidase from waste sludge (Tyagi et al., 2009). Nabarlatz et al. (2010) achieved the higher recovery the protease and lipase (hydrolytic enzymes) from waste activated sludge by ultrasonic (3.9 W/cm2, 10–20 min) assisted extraction method. Enzymes are commercially used in the food, pharmaceutical, fine chemical industries, detergent and diagnostics industries. However, cost-effective production of enzymes is very crucial from industrial point of view. Upto 40% of the production cost for industrial enzymes is accounted by the cost of the culture medium. Here, high cost benefits could be achieved by replacing the commercial medium with sludge (Tyagi et al., 2009).
Alcohol-Based Biofuel Cells
Published in Shelley Minteer, Alcoholic Fuels, 2016
Sabina Topcagic, Becky L. Treu, Shelley D. Minteer
Biofuel cells are electrochemical devices in which energy derived from biochemical reactions is converted to electrical energy by means of the catalytic activity of microorganisms and/or their enzymes. Unlike metal catalysts, biocatalysts are derived from biomatter, which is a renewable resource. Recent biofuel cell research has explored using enzymes as biocatalysts due to their availability and specificity. Enzymes are functional proteins whose purpose is to catalyze specific biochemical reactions by lowering the activation energy of the reaction, without undergoing a permanent chemical change itself. Enzymes can be manipulated and produced by genetic engineering or harvested and extracted from living organisms. Both means of acquiring enzymes are more cost effective than mining precious metals used as traditional catalysts. Biofuel cell catalysts are more environmentally friendly compared to heavy metal batteries due to the fact they naturally biodegrade. Another advantage of enzyme employment in biofuel cells is the enzyme specificity that pushes the fuel cell technology one step further. Specificity of the enzyme’s fuel utilization eliminates the need for employment of a salt bridge and therefore simplifies the fuel cell system [4].
A retrospect on recent research works in the preparation of zeolites catalyst from kaolin for biodiesel production
Published in Biofuels, 2023
Jane Mngohol Gadin, Eyitayo Amos Afolabi, Abdulsalami Sanni Kovo, Ambali Saka Abdulkareem, Moritiwon Oloruntoba James
Catalysis is an indispensable technology employed to accelerate and redirect chemical modifications. It is about triggering a boost in the rate of chemical change thanks to the involvement of a material referred to as a catalyst [78]. Harnessing of catalysts at low volumes for top-notch biodiesel quality and yield is puzzling to biodiesel researchers [79]. It is required that a good catalyst possess a controlled surface, protracted stability, good porosity, primed activity and chiefly, selectivity. Others are high rebuff to poisoning and deactivation, enough tolerance for temperature fluctuations, extreme forbearance to heating and finally, a display of mechanical strength by resistance to crushing [80]. A comparison with transesterification types that do not incorporate catalysts is presented in Table 4.
Non-linear radiative flow of unsteady Oldroyd-B nanofluid subject to Arrhenius activation energy
Published in Waves in Random and Complex Media, 2022
Muhammad Yasir, Masood Khan, Awais Ahmed
Due to the complexity of all the chemical responses in a system, it is more reasonable and simplistic to restrict to binary type only. The chemical reaction requires activation energy, which must be unrestricted to start. The least amount of energy required to operate molecules or atoms in a chemical system so that they can initiate a chemical reaction is referred to as activation energy. The reaction activation energy can be calculated using the Arrhenius equation, which explains how the rate constant varies with temperature. A chemical change occurs during chemical reaction, and one or more products are produced that differ in some way from the reactants. Many industrial applications require some kind of chemical reaction as a crucial stage in the manufacturing process. These kinds of reactions are typically conducted in chemical reactors, and they are frequently constrained by the degree of mass transfer attained. Instead of using an experimental approach, theoretical investigations into the impacts of activation energy on flow analysis are required. However, due to the complexity of the connection between chemical reactions and mass transportation, a few theoretical investigations are done in the existing study. The physical features of activation energy in chemical reactions are briefly described in a few articles. The effects of chemical reactions on binary reaction models with Arrhenius activation energy have been examined by Bestman [15]. Bestman [16] also investigated the influence of Arrhenius activation energy in the flow of a combustible mixture across a vertical pipe with radiation effect. Following that, the researchers continued their investigation on Arrhenius activation energy consequences under many intriguing circumstances with different flow configurations, as listed in Refs. [17–28].