EFFECT OF CARBON SOURCE ON THE PRODUCTION OF OXALIC-ACID AND HYDROGEN-PEROXIDE BY BROWN-ROT FUNGUS PORIA-PLACENTA

Oxalic acid and hydrogen peroxide have been suggested to be essential in the degradation of wood carbohydrates by brown-rot fungi. The produ ction of oxalic acid, hydrogen peroxide and endo-beta-1,4-glucanase ac tivity by the brown-rot fungus Poria placenta was studied on crystalli ne cellulose, amorphous cellulose and glucose media. Oxalic acid and h ydrogen peroxide by P. placenta were clearly produced on culture media containing either crystalline or amorphous cellulose. Oxalic acid and hydrogen peroxide were formed simultaneously and highest amounts of o xalic acid (1.0 g l(-1)) and hydrogen peroxide (39.5 mu M) were obtain ed on amorphous cellulose after 3 weeks cultivation. On glucose medium the amounts were low. The endoglucanase activity was observed to incr ease during the cultivation and was most pronounced on glucose medium and thus indicated the constitutive characteristics of the brown-rot c ellulases.