Methanol anaerobic degradation

Estimated Free Energy Changes of Selected Biological Reactions Involved in the Anaerobic Degradation of Formaldehyde and Methanol... 

Catabolism is concerned with the breakdown and degradation of biological compounds within living tissue and cells. For the purposes of this chapter it will be considered as being primarily concerned with the utilization of amino acids to produce chemical energy for life processes. This may occur by aerobic or anaerobic mechanisms with the ultimate end-product being CO2 or in some cases a more reduced form such as methanol, ethanol, or formate. 

Essential oils are produced from dry or fresh plant materials by distillation. Citrus oils are the only essential oils obtained by cold pressing. Several technologies have been developed for their production (1, 3,9,12,26). Dry distillation is a thermal degradation process to obtain tar such as birch, cade, pine, and cedar tars. This process involves applying intense heat to scrap wood material from the top in totally anaerobic condition. Because of thermal degradation, a viscous dark-colored, tarry liquid with a smoky odor separates and collects in a container underneath the vessel. This material separates into two layers in 15-20 days. Tar sinks to the bottom and the oily layer floats on top of water. It contains methanol, acetic acid, and degradation products of lignin (1, 3, 9-14). 

The process of direct anaerobic-aerobic treatment resulting in humification of TNT and its congeners offers a convincing and simple concept (Fig. 18 process II) for the remediation of soil contaminated with TNT and congeneric compounds. This is evident by comparison with the alternative process I (Fig. 18), which requires the desorption of the contaminants by innocuous solvents such as methanol or ethanol. Desorption plus the separation of particles must precede the actual anaerobic process of polynitrotoluene reduction. Furthermore, the anaerobic stage requires a microbial system which degrades TAT and diaminotoluenes productively or at least to such an extent that subsequent aerobic treatment results in complete mineralization. 

Other important munitions contaminants receiving study are RDX and HMX. Strict anaerobes appear to degrade these compounds efficiently (18, 22, 34). RDX appears to be reduced sequentially to its nitroso derivatives, and formaldehyde and methanol seem to be biodegradation products (22). The basis for the diauxic process by which both anaerobic consortia (13) and pure Clostridium strains (27) degrade TNT from munitions mixtures prior to RDX needs investigation. Are different reductive enzyme systems used for TNT and RDX, and are they induced sequentially Do similar enzymes reduce both, but preferentially reduce the substrates and their partial reduction products according to their redox potentials The reviews of Kaplan (18) and Walker and Kaplan (34) provide a summary of RDX and HMX... 

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