China
Africa
Explore chapters and articles related to this topic
Environmental Fate and Transport of Solvent-Stabilizer Compounds
Published in Thomas K.G. Mohr, William H. DiGuiseppi, Janet K. Anderson, James W. Hatton, Jeremy Bishop, Barrie Selcoe, William B. Kappleman, Environmental Investigation and Remediation, 2020
Thomas K.G. Mohr, James Hatton
The acclimation of a microbial community to one chemical substrate can result in acclimation to chemical substrates that are structurally similar. Cometabolism is the fortuitous degradation of a compound that microorganisms cannot utilize as growth substrates, that is, the compound does not provide a nutrient or energy source for the degrading organisms (Alexander, 1994; Hyman, 1999). For example, enzymes produced during the microbial degradation of the cyclic ether tetrahydrofuran (THF) also degrade 1,4-dioxane. If a synthetic organic compound is transformed by cometabolism, the mass of enzymes involved will be independent of the mass of the compound transformed and will be determined by the mass of the compound that induces the enzymes (Grady et al., 1997).
Hazardous Organic Waste Amenable to Biological Treatment
Published in Daphne L. Stoner, Biotechnology for the Treatment of Hazardous Waste, 2017
Cometabolism is the degradation of organic compounds usually via nonspecific enzymatically mediated transformations.4 In contrast to mineralization, cometabolism does not result in the increase in cell biomass or energy. Consequently, the ability to cometabolize a compound is not a benefit to the microorganism. In fact, another substrate is necessary in order to satisfy growth and energy requirements of the cell. Typically, cometabolism results in the modification or transformation of the organic material and does not result in the complete destruction of the molecule. While cometabolism can result in the complete destruction of an organic molecule, the accumulation of potentially toxic intermediates in the environment can occur.
Biodegradation-based remediation – overview and case studies
Published in Katalin Gruiz, Tamás Meggyes, Éva Fenyvesi, Engineering Tools for Environmental Risk Management – 4, 2019
M. Molnár, K. Gruiz, É. Fenyvesi
Chlorinated solvents (e.g. TCE), chlorinated pesticides, polychlorinated biphenyls (PCBs), and alkylbenzene sulfonates (ABS) are chemicals that are often transformed through cometabolism (Alexander, 1994; Wackett, 1995; Schink, 2005; Alvarez & Illman, 2006; Arp et al., 2001). Wide range of conversions, reaction types and products are associated with cometabolism. Among cometabolic conversions that appear to involve single enzyme, the reaction may be hydroxilations, oxidations, denitrations, deaminations, hydrolyses, acylations, or cleavages of ether linkages, but many of the conversions are complex and involve several enzymes (Alexander, 1994; Fritsche & Hofrichter, 2008).
Nonionic surfactant enhanced biodegradation of m-xylene by mixed bacteria and its application in biotrickling filter
Published in Journal of the Air & Waste Management Association, 2018
Liping Wang, Ruiwei Xu, Bairen Yang, Shaohua Wei, Ningning Yin, Chun Cao
On the other hand, the biodegradation effects of hydrophobic VOCs are usually limited by their low aqueous solubility and the mass transfer rate of hydrophobic VOCs from gas phase to liquid phase (Cheng, He, and Yang 2016a, 2016b; Wang, Yang, and Cheng 2014). Applying surfactants in BTF is an effective way to improve the removal efficiency of hydrophobic VOCs by enhancing their bioavailability. The role of surfactant in facilitating hydrophobic VOCs removal in BTF systems has been the subject of several studies (Cheng, He, and Yang 2016b; Song, Yang, and Zeng 2012; Wang, Yang, and Cheng 2013, 2014). The use of surfactants could improve the availability of contaminants and supply degradable carbon sources to enhance the cometabolism of contaminants (Amin, Rahimi, and Bina 2016; Chen, Zhu, and Qian 2013; Tian, Yao, and Liu 2016). Cheng, He, and Yang (2016b) reported that the anionic surfactant sodium dodecyl sulfate (SDS) could be degraded by microorganisms and enhance hexane removal. Ramirez, Jones, and Heitz (2012) have indicated that the nonionic surfactant Brij 35 could improve the performance of BTF and influence of carbon dioxide production. Woertz and Kinney (2004) have demonstrated that the nonionic surfactant Tween 20 could act as a stimulant to promote inoculum growth and development. Wang, Yang, and Cheng (2013) confirmed that Tween 20 could increase ethylbenzene removal efficiency by 19% under the optimal operating conditions. However, utilization of nonionic surfactant such as polyoxyethylene sorbitan monooleate (Tween 80) in BTF systems is rarely reported in the literature. Hence, the effect of Tween 80 addition on bacterial growth and BTEX degradation merits further study in terms of the biological treatment process.