Most degradation studies employing Phanerochaete have been carried out in solid cultures or in shallow liquid stationary or shake cultures (Ander and Eriksson 1977; Hatakka 1985). Packed-bed bioreactor configurations have been mainly used to study the ligninolytic enzymes and degradative abilities of P. chrysosporium (Lewandowski et al. 1990; Linko 1988). In view of this it was decided to examine the effect of the fungus on the industrial waste in a 2 l packed-bed reactor.
The strain of P. cinnabarinus was inoculated onto a nylon web cube support (0.5 cm3 of Scotchbrite®). The effluent was prepared in a defined medium (Tien and Kirk 1988) which was modified by increasing the final concentration of diammonium tartrate to 0.8 g/l to give a carbon to nitrogen ratio of 38.3:1. Although it stimulated phenoloxidase activity, veratryl alcohol (40 mM) was omitted in this trial because it retarded mycelial growth, inhibited glucose and nitrogen utilization and delayed decolorization. Addition of veratryl alcohol at the time of inoculation may interfere with fungal metabolism (Tonon and Odier 1988).
The medium was circulated through the reactor at 0.45 l/h and samples were taken daily and analyzed for glucose concentration, available nitrogen, and oxidative enzyme activity which at this stage was termed phenoloxidase. A control reactor lacking the effluent was also used.
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