Journal of Biotechnology, 13 (1990) 211-221 211 Elsevier BIOTEC 00473 The effect of culture conditions on the production of lignin modifying enzymes by the white-rot fungus Phlebia radiata M.-L. Niku-Paavola 1, E. Karhunen 1, A. Kantelinen 1, L. Viikari 1, T. Lundell 2 and A. Hatakka 2 I VTT, BiotechnicalLaboratory, Espoo, Finland," 2 DepartmentofMicrobiology, UnioersityofHelsinki, Helsinki, Finland (Received 21 June 1989; accepted 17 October 1989) Summary The extracellular enzymes synthesized by Phlebia radiata Fr. 79 (ATCC 64658) under various cultivation conditions were studied in order to find out suitable enzyme combinations for the modification of lignin. The fungus produced lignin peroxidase (LIP, ligninase), manganese-dependent peroxidase (MnP) and laccase (benzenediol : oxygen oxidoreductase, EC 1.10.3.2) in various proportions depending on the cultivation conditions. Addition of veratryl alcohol increased lignin per- oxidase and manganese-dependent peroxidase activities both in agitated and non- agitated flask cultures. Laccase production was more enhanced by the addition of benzyl alcohol and veratric acid. However, the highest lignin peroxidase activities were obtained using a non-phenolic dimeric /3-0-4 model compound. Pressure ground wood (PGW), chemithermomechanical pulp (CTMP) or spruce shavings in the bioreactors decreased the amount of lignin peroxidase, whereas laccase and manganese-dependent peroxidase activities increased. Lignin peroxidase and partly manganese-dependent peroxidase was adsorbed on the lignocellulose substrate, but Correspondence to: M.-L. Niku-Paavola, VTT, Biotechnical Laboratory, Tietotie 2, SF-02150 Espoo, Finland. Abbreoiations: LIP1,2,3= lignin peroxidase isozymes of Phlebia radiata; MnP = manganese-dependent peroxidase of Phlebia radiata; PGW = pressure ground wood; CTMP--chemitliermomechanical pulp; MWL = milled wood lignin; VALC = veratryl alcohol (3,4-dimethoxybenzylalcohol); VACID = veratric acid (3,4-dimethoxybenzoic acid); BALC == benzyl alcohol; fl-O-4 = non-phenolic fl-O-4 dimer [1-(3,4-di- methoxyphenyl)-2-(2-methoxyphenoxy)propane-l,3-diol]; IEF = isoelectric focusing; SDS = sodium dodecyl sulphate; PAGE = polyacrylarnide gel electrophoresis; ABTS = 2,2'-azinodi-3-ethyl- benzothiazoline-6-sulphuric acid; LN-ADMS= low-nitrogen asparagine dimethylsuccinate medium. 0168-1656/90/$03.50 © 1990 Elsevier Science Publishers B.V. (Biomedical Division)