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Soil Microbial Enzymes and Their Importance, Significance, and Industrial Applications
Published in Pankaj Bhatt, Industrial Applications of Microbial Enzymes, 2023
Hemant Dasila, Sarita Joshi, Sudipta Ramola
There are various types of hydrolytic dehalogenases, which can be categorized into haloacid dehalogenases, aliphatic dehalogenases, fluoroacetate dehalogenases, and halohydrin dehalogenases. Aliphatic dehalogenases include haloalkane dehalogenases, which convert haloalkanes to their corresponding proton, halides, and alcohol as a result of catalysis of hydrolytic cleavage of carbon halogen bonds. Haloacid-dehalogenase-like enzymes cover phosphohydrolases found in the bacterial population of marine and other environments. Dehalogenation of fluoroacetate performed by fluoroacetate dehalogenases is capable of hydrolyzing the strongest bond (i.e., carbon-fluorine bond). During the process of degradation, the displacement of chlorine by nucleophilic attack of aromatic halogens is catalyzed by haloaromatic dehalogenase (Oyewusi et al., 2020).
Nature’s Green Catalyst for Environmental Remediation, Clean Energy Production, and Sustainable Development
Published in Miguel A. Esteso, Ana Cristina Faria Ribeiro, A. K. Haghi, Chemistry and Chemical Engineering for Sustainable Development, 2020
Benny Thomas, Divya Mathew, K. S. Devaky
Halogenated compounds produced by both natural activities and man-made efforts are present everywhere in the soil. These compounds may be hazardous, toxic, mutagenic, or carcinogenic. Haloalkane dehalogenases are useful for the hydrolysis of carbon halogen bonds present in the various halogens containing contaminants and produce alcohol and halides.51 The active site of haloalkane dehalogenase is present between the main domains of an eight-stranded β-sheet helices. First haloalkane dehalogenase discovered from the bacterium Xanthobacter autotrophicus has the ability to degrade 1, 2-dichloroethane. Several dehalogenases have been cloned and characterized from Gram-positive and Gram-negative haloalkane degrading bacteria.
Biotransformations in Deep Eutectic Solvents
Published in Pedro Lozano, Sustainable Catalysis in Ionic Liquids, 2018
Vicente Gotor-Fernández, Caroline Emilie Paul
Microbial haloalkane dehalogenases are valuable enzymes catalyzing the hydrolytic cleavage of carbon-halogen bonds, however, their practical applications are usually hampered due to the poor solubility of their substrates in aqueous medium. With this challenge, DES-water binary mixtures were employed in two model dehalogenation reactions, such as the one over 1-iodohexane and the kinetic resolution of racemic 2-bromopentane (Stepankova et al. 2014). Interestingly, the three haloalkane dehalogenases tested were active in ChCl:Gly (1:2)-glycine buffer pH 8.6 systems at 37°C.
Haloalkane adsorption into 1-D ensembles’ channels: Zn(II) coordination polymers
Published in Journal of Coordination Chemistry, 2018
Haeri Lee, Daseul Lee, Ok-Sang Jung
Functional molecular ensembles have been constructed of desirable molecular arrays of simple skeletons via intermolecular interactions [1–7]. Such well-ordered molecular arrays modulate the channels’ functional attributes such as cavity size, solvate molecule number, and hydrophilicity [8–12]. The driving forces behind the formation of molecular ensembles are an interesting topic to those seeking to understand the key role of arrayed ensembles’ channels [13–15]. Meanwhile, reversible exchange of solvate molecules within suprachannels has been studied [16–18]. The efficiency of molecular adsorption into specific channels of supramolecular materials is influenced by control of lining properties such as surface area, hydrophobicity, and chirality [19–22]. Thus, efficient task-specific porous molecular materials in the fields of adsorption, gas storage, molecular recognition, anion exchange, and catalysis have been developed [23–26]. Momentous progress has been made in the study of unique ensembles’ channels in arrays of coordination polymers consisting of appropriate metal ions with organic ligands of varying flexibility, length, and binding angle [7–10], even though serendipitous motifs frequently have been constructed owing to the presence of unpredictable weak interactions such as hydrogen bonds, van der Waals interactions, M···M interactions, and π···π interactions [11]. The adsorption and discrimination of hazardous haloalkane molecules recently has become a hot issue. Haloalkanes have been found both naturally in marine environments and artificially in refrigerants, solvents, propellants, and fumigants [27–30]. For instance, many haloalkanes, including the chlorofluorocarbons, have attracted wide attention because, when exposed to ultraviolet light found at high altitudes, they become active and damage the Earth’s protective ozone layer [31, 32]. Selective capturing of such haloalkanes is a significant issue relevant to their successful reduction.