China
Africa
Explore chapters and articles related to this topic
Reuse of Treated Wastewater through Emerging Technologies
Published in Maulin P. Shah, Wastewater Treatment, 2022
Rifat Ara Masud, Farzana Yeasmin, M. Mehedi Hasan, Md. Kamruzzaman
An enzyme-redox mediator approach for remediation/degradation of different organic pollutants (wide spectrum of aromatic compounds) prevailing in the industrial effluent has attracted a great deal of attention recently. In the presence of certain redox mediators, several recalcitrant compounds can be degraded by specific enzymes. Redox mediators speed up the degradation reaction rate by transporting electrons from the bulk electron donors or from biological oxidation of primary electron donors to the electron-accepting organic compounds. With high redox potentials (>900 mV), easily diffusible, low-molecular-weight redox mediators attack the recalcitrant structural analogs and are able to be migrated into the aromatic structure of the specific compound. These redox mediators enhance the range of substrates for the enzymes and efficiency of degradation of the recalcitrant compounds by severalfold. Frequently used redox mediators include 1-hydroxybenzotriazole, violuric acid, veratryl alcohol, 2-methoxyphenothiazone, anthraquinone, 2,6- disulfonic acid, 3-hydroxyanthranilic acid, N-hydroxyacetanilide, phenol red, dichlorophenol red, syringaldehyde, acetosyringone, etc.
Other Modification Processes
Published in Dick Sandberg, Andreja Kutnar, Olov Karlsson, Dennis Jones, Wood Modification Technologies, 2021
Dick Sandberg, Andreja Kutnar, Olov Karlsson, Dennis Jones
Laccase is currently used in a variety of bioprocesses (Harris 2017), and particularly for bioremediation, biosensors, dye removal, food and beverage processing and pulp and paper applications. In the pulp and paper sector, the use of laccase has mainly focussed on the delignification of feedstocks necessary for paper-based products. Lignin is normally removed in chemical pulping using toxic chlorine-based chemicals, but this does not achieve total removal of all the lignin components. Total removal of lignin requires initiating the degradation of polysaccharides, which can reduce the product quality, but the addition of laccase facilitates the lignin removal (Camarero et al., 2007), and the process can be enhanced through the use of mediators such as acetosyringone, syringaldehyde or p-coumaric acid. The role of the mediators in the process is shown in Figure 5.3.
Origins of Effluent Chemicals and Toxicity: Recent Research and Future Directions
Published in Mark R. Servos, Kelly R. Munkittrick, John H. Carey, Glen J. Van Der Kraak, and PAPER MILL EFFLUENTS, 2020
The majority of the mass of AOX in bleached kraft effluents using elemental or ECF bleaching is high molecular weight (>1000 Da) materials (Dahlman et al. 1996). However, the structure of the high molecular weight material is different depending on the bleaching process e.g., ECF, TCF (Dahlman et al. 1994a). Approximately half of the AOX in a softwood ECF effluent was high molecular weight while a major part of TCF hardwood pulp was low molecular weight (Dahlman et al. 1996). Halogenated high molecular weight material in softwood TCF effluents also appears to be composed of lower molecular weight material than that in softwood ECF effluents. Dahlman et al. (1996) have explored new methods to further examine and compare the structure of lignin. A method using thioacidolysis and GC/HRMS to detect chlorinated nonphenolic alkyl-aryl ether structures has been developed. Previous work has shown that part of the AOX is found in the lignin-derived phenolic structural elements. Ristolainen (1994) examined high molecular weight lignin fractions dissolved during TCF bleaching of a hardwood kraft pulp which were characterized by analyzing the alkaline oxidation products. Ultrafiltration and HPLC indicated a variety of phenolic products including acetosyringone, acetovanillone, syringaldehyde, vanillin and syringic acid. Differences in the total amount and composition of the product fraction from different bleaching stages were detected.
Establishment and elicitation of transgenic root culture of Plantago lanceolata and evaluation of its anti-bacterial and cytotoxicity activity
Published in Preparative Biochemistry & Biotechnology, 2021
Samaneh Rahamouz-Haghighi, Khadijeh Bagheri, Ali Sharafi, Hossein Danafar
The transformation efficiency of many plants like Withania somnifera[50] and Rauwolfia serpentine[51] has increased in presence of Acetosyringone. Muthusamy et al. employed 75 µM of Acetosyringone and indicated that the presence of Acetosyringone increased the efficiency of transformation up to 90% while in the absence of Acetosyringone the transformation efficiency was 36.6%.[52] In another research, Bhagat et al. stated that applying 125 µM of Acetosyringone, the transformation efficiency increased up to 55% whereas in the absence of Acetosyringone, the transformation efficiency was around 20%.[51] In the same line, Amoah and colleagues obtained an increased number of explants producing blue spots with 200 µM Acetosyringone.[53] Paul et al. used different concentrations of Acetosyringone to evaluate optimal transformation efficiency. According to their results, 150 µM concentration determined as an optimal condition[54] However, they pointed out that Acetosyringone at a concentration up to 200 µM was considered to be nontoxic to Agrobacterium, but reduced transient transformation efficiency suggesting 150 µM was optimal for patchouli leaf transformation.[55]