Lignocellulose biodegradation by Agaricus bisporus during solid substrate fermentation

Agaricus bisporus was cultivated axenically on wheat straw compost. Analysis of this culture medium during growth and fruiting showed that the lignin fraction of straw was degraded preferentially during the vegetative growth phase, whereas cellulose was degraded after the emergence of the fruit bodies. A novel technique was developed, whereby natural or synthetic radiolabelled lignin was mixed intimately with axenic compost and the rate of mineralization to CO2 throughout the life-cycle of A. bisporus was monitored continuously without culture disturbance. Mineralization rates were maximal during the vegetative growth phase and the onset of fruiting brought a decrease of this activity. A mutant strain of A. bisporus, which was unable to develop fruiting bodies, was shown to mineralize radiolabelled lignin continuously.