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ePaper created 2014-05-07, 13:23:14 | version 1.30.01
105 References [1] Wong, D. W. S. (2009) Structure and action mechanism of lig- ninolytic enzymes, Appl. Biochem. Biotechnol. 157: 174 – 209 [2] Qi-he, C.; Krügener, S.; Hirth, T.; Rupp, S.; Zibek, S. (2011) Co- cultured production of lignin-modifying enzymes with white-rot fungi, Appl. Biochem. Biotechnol. 165: 700 – 718 [3] Bugg, T. D. H.; Ahmad, M.; Hardiman, E. M.: Singh, R. (2011) The emerging role for bacteria in lignin degradation and bio- product formation, Curr. Opin. Biotechnol. 22: 394 – 400 Funding We would like to thank the German Federal Ministry of Food and Agriculture (BMEL) and the Agency for Renewable Resources (FNR) for funding the project “Lignocellulose Bioraffinerie Phase II”, promotional reference 22019309. Project partners and further information www.lignocellulose-bioraffinerie.de involved in the degradation of lignin via similar mechanisms to those of the lignin or manganese peroxidases, and intracellu- lar enzymes which metabolize lignin fragments, are of interest [3]. In the genome of a strain of Pseudonocardia sp., which was sequenced at the Fraunhofer IGB, we were able to find a number of putative enzymes for the metabolism of aromatic compounds. An interesting reaction here is the demethylation of vanillic acid by a monooxygenase, which generates a new functional hydroxyl group (Fig. 3). DyP-type peroxidases from a variety of ligninolytic bacteria are being expressed and their catalytic properties investigated. The results should provide information as to what extent DyP-type peroxidases in bacteria assume the role of lignin- peroxidases. Outlook Enzymes that are very promising with respect to the modifi- cation and the degradation of lignin shall be produced on a larger scale and made available for industrial applications. 1 Co-culture of Pleurotus ostreatus and Phlebia radiata in a shaking flask after 168 h incubation at 25°C. In the submerged culture it was possible to increase the enzyme production. 2 Ligninolytic enzyme activity in the culture supernatant of various bacterial strains. 3 Enzymes of protocatechuic acid metabolism from Pseudonocardia sp. may be of interest for the material utilization of lignin. 3 Dr.-Ing. Susanne Zibek Phone +49 711 970-4167 susanne.zibek@igb.fraunhofer.de Priv.-Doz. Dr. Steffen Rupp Phone +49 711 970-4045 steffen.rupp@igb.fraunhofer.de Contacts dihydroxyphthalic acid decarboxylase vanillic acid monooxygenase 3,4-protocatechuic acid dioxygenase 4,5-protocatechuic acid dioxygenase 1 2 3 4 3,4-hydroxyphthalic acid 4-carboxy-2-hydroxymuconic acid semialdehyde protocatechuic acid vanillic acid 3-carboxy-cis-cis-muconic acid 1 2 3 4 HO HO O2 O2 H2O, NAD+ , CH2O NADH, H+ , O2 CO2 HO OH OH HO HO OH O O O OH O O COOH COOH COOH CH3 OH HO HO O O O