Biodegradability scheme

Figure 20. Quinoline biodegradation scheme, proposed for Comamonas sp. TKV3-2-1.

Branched and 70% biodegradable) Scheme 10. Linear and branched polyaspartic acids. 

Increasing peroxidisability and biodegradability Scheme 2 Relative stability of hydrocarbon polymers in the environment[8]... 

Lactic acid and levulinic acid are two key intermediates prepared from carbohydrates [7]. Lipinsky [7] compared the properties of the lactide copolymers [130] obtained from lactic acid with those of polystyrene and polyvinyl chloride (see Scheme 4 and Table 5) and showed that the lactide polymer can effectively replace the synthetics if the cost of production of lactic acid is made viable. Poly(lactic acid) and poly(l-lactide) have been shown to be good candidates for biodegradeable biomaterials. Tsuji [131] and Kaspercejk [132] have recently reported studies concerning their microstructure and morphology. 

Polylactic acid (PLA) has been produced for many years as a high-value material for use in medical applications such as dissolvable stitches and controlled release devices, because of the high production costs. The very low toxicity and biodegradability within the body made PLA the polymer of choice for such applications. In theory PLA should be relatively simple to produce by simple condensation polymerization of lactic acid. Unfortunately, in practice, a competing depolymerization process takes place to produce the cyclic lactide (Scheme 6.10). As the degree of polymerization increases the rate slows down until the rates of depolymerization and polymerization are the same. This equilibrium is achieved before commercially useful molecular weights of PLA have been formed. 

The biodegradation of branched-chain alkanol ethoxyethylates was carried out by the standard OECD confirmatory tests and the metabolites fractionated after solid-phase extraction. The structures of the metabolites were determined by electrospray mass spectrometry and this made it possible to derive a scheme for the partial degradation of the compounds (Di Corcia et al. 1998). 

Zwank L, M Berg, M Eisner, TC Schmidt, RP Schwarzenbach, SB Haderlien (2005) New evaluation scheme for two-dimensional isotope analysis to decipher biodegradation processes application to groundwater contamination by MTBE. Environ Sci Technol 39 1018-1029. 

A number of heteroaromatic monothiocarboxylic acids are formed by Pseudomonas sp. From P. putida, there was isolated pyridine-2,6-di-(mon-othiocarboxylic acid) 46 (Scheme 16). Of interest is the fact that in P. stutzeri KC, a copper complex of 46 is the active agent for a one electron transfer in the bacterial biodegradation of CCI4. Methylation of P. putida extracts provides a number of related structures such as 47. In addition, a P. fluorescens sp. contains 8-hydroxy-4-methoxy-quinoline-2-monothiocarboxylic acid 48.98... 

Carboxylic Acids Obtained by Fermentation of Carbohydrates Lactic (2-hydroxy-propionic) acid obtained by fermentation of glucose and polysaccharides is used by NatureWorks (Cargill/Dow LLC) to prepare polylactide (PLA), a biodegradable or recyclable polymer with a potential production of 140000 t a-1 (Scheme 3.4) [23], This and other potential useful reactions from lactic acid have been reviewed by Datta and Henry [24],... 

Triglycerides are nontoxic, biodegradable and renewable molecules which are being used as substrate for the synthesis of a variety of useful molecules such as glycerol esters, fatty acid alkyl esters, triacetin, ketals, acetals, glycerol carbonates, etc (Scheme 1). 

Benzoic acid, a common food preservative, may be a suitable substrate to achieve biostimulation. It is a relatively inexpensive, harmless aromatic compound that has been previously used in analogue enrichment1 schemes to enhance biodegradation of the aromatic herbicide, 2,3,6-trichlorobenzoic acid (2,3,6-TBA) [336]. Benzoate ion is also an intermediate in the toluene pathway and it can induce related enzymes involved in the degradation of toluene and m-and p-xylenes [336]. In addition, the anionic nature of benzoic acid would minimize its retardation and facilitate its distribution when injected into an... 

Scheme 5. Involvement of epoxide hydrolases in the biodegradation of aromatics and alkenes...

This indicates the possibility of making addition polymers biodegradable by the introduction of ester linkages in to the backbone. Since the free radical ring-opening polymerization of cyclic ketene acetals, such as 2-methylene-1,3-dioxepane (1, Scheme I), made possible the introduction of ester groups into the backbone of addition polymers, this appeared to be an attractive method for the synthesis of biodegradable addition polymers. 

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