PEROXIDASE AND ARYL METABOLITE PRODUCTION BY THE WHITE-ROT FUNGUS BJERKANDERA SP. STRAIN BOS55 DURING SOLID-STATE FERMENTATION OF LIGNOCELLULOSIC SUBSTRATES

Ligninolytic enzymes and secondary metabolite production by Bjerkander a sp. strain BOS55 were monitored during solid state fermentation (SSF ) on two lignocellulosic substrates, beech wood and hemp stem wood (HS W). After 6 weeks of SSF, the fungus was responsible for removing 27 a nd 39 % of the Klason lignin as well as 43 and 70 % of the apolar extr actives on beech and HSW, respectively. The lignin degradation during beech wood decay was very selective. On both substrates, high activiti es of lignin peroxidase (LiP) and manganese peroxidase (MnP) were dete cted. The peak activity of LIP was 660 nmol ml(-1) min.(-1) on HSW and that of MnP was 1320 nmol ml(-1) min.-' on beech wood. The presence o f several LiP and MnP isoenzymes at different times during the SSF was demonstrated by FPLC profiles of these heme proteins. The production of the secondary aryl metabolites, veratryl alcohol and 3-chloro-p-ani saldehyde, reached peak concentrations of 820 and 90 mu M, respectivel y. The enhanced production of these secondary metabolites compared to defined liquid cultures is suggested to be due to the release of ligni n degradation products serving as alternative precursors for their bio synthesis. The high production of veratryl alcohol, which is a cofacto r known to protect LiP from inactivation by physiological levels of H2 O2, may account for the high production of active LiP on the lignocell ulosic substrates.