Synthetic lignin

Perez J, TW Jeffries (1990) Mineralization of C-ring-labelled synthetic lignin correlates with the production of lignin peroxidase, not of manganese peroxidase or laccase. Appl Environ Microbiol 56 1806-1812. 

Gupta JK, Sharma P, Kern HW et al (1990) Degradation of synthetic lignins and some lignin monomers by the yeast Rhodotorula glutinis. World J Microb Biotechnol 6 53-58... 

Noguchi et al. (8) synthesized precursors of lignin biosynthesis (i.e., coniferyl and sinapyl alcohols) in which the side chain and methoxy groups were doubly labeled by and H, prepared the DHP (synthetic lignin) from them, and treated the DHP with the laccase. These results showed that about 25% of Hs of the a- and -positions were removed in a ratio of one to one, respectively, and that the methoxyl group of a syringyl unit was de-methylated easier than that of a guaiacyl. 

Both a synthetic lignin model substrate and the natural metabolites of the white-rot fungus were oxidized by this extracellular peroxidase. The possible roles of this nitrogen recycling system and the cinnamate pathway, which are involved in the secondary metabolism of L-phenylalanine in brown-rot and white-rot fungi, are discussed in relation to wood decay processes. 

Lignin peroxidase of Phanerochaete chrysosporium catalyzes the ring cleavage of /3-0-4 lignin substructure model compounds and synthetic lignin (DHP). A mechanism for the ring cleavage by the enzyme is described. 

The purpose of the present paper is to describe the aromatic ring cleavage of lignin substructure model compounds by white-rot basidiomycetes and by lignin peroxidase of P. chrysosporium. The aromatic ring cleavage of synthetic lignin (DHP) by the enzyme will also be described. 

Figure 7. Preparation of synthetic lignin 16, ethylated copolymer of coniferyl alcohol 7 and arylglycerol-/ -syringaresinol ether 6. In 16, the rectangular enclosure represents an assumed structure of the moiety derived from 7.

Figure 9. Degradation products of synthetic lignin (DHP) 16 by lignin peroxidase. 8, 9 and 11 Aromatic ring cleavage products 13 and 14 / -0-4 bond cleavage products.

Hammel, K. E. Moen, M. A. (1991). Depolymerization of a synthetic lignin in vitro by lignin peroxidase. Enzyme Microbial Technology, 13, 15-18. 

Gonzalez et al. (1996, 1999) Marine Lignin Mineralization of radiolabeled, synthetic lignin Oligonucleotide probes Yes 25 days Approximately 1/3 of lignin mineralized by 3 bacterial isolates Bacterial isolates from a- and y-Proteobacteria accounted for up to 55% of total community DNA... 

Reid, I.D. (1991). Nutritional regulation of synthetic lignin (DHP) degradation by Phlebia (Merulius) tromellosea Effect of nitrogen. Can. J. Bot., 69 156-160. 

Brunow G, Sipila J, Makela T (1989) On the mechanism of formation of non-cyclic benzyl ethers during lignin biosynthesis Holzforschung 43 55-59 Ede RM, Brunow G, Simola LK, Lemmetyinen J (1990) Two-dimensional H- H chemical shift correlation and J-resolved NMR studies on isolated and synthetic lignins Holzforschung 44 95-101... 

Benner R., Maccubbin A. E., and Hodson R. E. (1984) Anaerobic biodegradation of the lignin and polysaccharide components of lignocellulose and synthetic lignin by sediment microfiora. Appl. Environ. Microbiol. 47, 998-1004. 

A.V. Vahatalo, K. Salonen, M. Salkinoja-Salonen, A. Hatakka (1999). Photochemical mineralization of synthetic lignin in lake water indicates enhanced turnover of aromatic organic matter under solar radiation. Biodegradation, 10,415-420. 

As early as 1948, Jones [63,64] conducted a comprehensive study of lignin using mid-IR spectroscopy. The IR studies by others that followed focused on, for example, synthetic lignin (DHP), lignin in situ, Braun s lignin, and enzyme lignin. Hergert... 

In the following section, which briefly describes the various experiments, spectra from various synthetic and isolated lignins will be used for illustration synthetic lignins have the advantage of containing all of the major lignin unit types, without the complications of carbohydrates. 

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