Laccase modification

Laccase Modification of the Physical Properties of Bark and Pulp of Loblolly Pine and Spruce Pulp... 

Perez J, De La Rubia T, Ben Hamman O, And Martinez J (1998) Phanerochaete flavido-alba laccase induction and modification of manganese peroxidase isoenzyme pattern in decolorized olive oil mill wastewaters. Appl Environ Microbiol 64(7) 2726—2729... 

Polyphenol oxidase occurs within certain mammalian tissues as well as both lower (46,47) and higher (48-55) plants. In mammalian systems, the enzyme as tyrosinase (56) plays a significant role in melanin synthesis. The PPO complex of higher plants consists of a cresolase, a cate-cholase and a laccase. These copper metalloproteins catalyze the one and two electron oxidations of phenols to quinones at the expense of 02. Polyphenol oxidase also occurs in certain fungi where it is involved in the metabolism of certain tree-synthesized phenolic compounds that have been implicated in disease resistance, wound healing, and anti-nutrative modification of plant proteins to discourage herbivory (53,55). This protocol presents the Triton X-114-mediated solubilization of Vida faba chloroplast polyphenol oxidase as performed by Hutcheson and Buchanan (57). 

Barsberg, S. and Hassingboe, J. (2003). Laccase catalysed enhancement of the autoadhesion of TMP fibres. In Proceedings of the First European Conference on Wood Modification, Ghent, Belgium, Van Acker, J. and Hill, C.A.S. (Eds.), pp. 381-388. 

Gianfreda and Bollag (1994) investigated the behavior of laccase and peroxidase in the presence of a montmorillonite, a kaolinite, and a silt loam soil. They observed considerable variation in the retained activities of the two enzymes immobilized on the different supports as well as variation in the amount of each enzyme sorbed (Table 2.10). Interestingly enough, laccase immobilized on montmorillonite showed a higher specific activity (118%) than that of the free enzyme. This may be attributed to the steric modification of the immobilized enzyme or possibly due to the catalytic ability of montmorillonite itself. Their studies showed that the performance of these enzymes is significantly affected by soil mineral colloids. 

Since laccase and Mn-peroxidase have about the same molecular size as ovalbumin, they must also be unable to penetrate the cell walls before decay is well advanced. However, chelated Mn(III), the direct product of Mn-peroxidase action, should be able to diffuse into the cell walls, and may be responsible for the initial modification of the lignin in the secondary walls and the middle lamellae. 

Apart from natural materials, oxidoreducates have been used to modify synthetic polymers. For example, using peroxidase, poly(4-hydroxystyrene) has been functionalized with aniline while poly(p-phenylene-2,6-benzobisthiazole) has been rendered more hydrophilic [22, 23]. Other authors have demonstrated that phenolics can be covalently bound to amino-functionalized polymers by using laccase resulting in increased fire resistance [13]A large number of scientific reports are available on enzymatic functionalization of poly(alkyleneterephthalate)s. Polyester fibers account for 73% of all synthetic fibers on the market with an annual production of approx. 27 million tons [24]. Similarly, polyamides and polyacrylonitriles have significant market shares. In contrast to natural polymers discussed above, hydrolases have shown higher potential for modification of these synthetic materials than oxidoreducates. 

Witayakran, S., and Ragauskas, A.J. (2009) Modification of high-lignin softwood kraft pulp with laccase and amino acids. Enzyme Microb. Technol., 44 (3), 176-181. 

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