Degradation of tannins in spent coffee grounds by Pleurotus sajor-caju.

Pleurotus sajor-caju PL27, a white rot fungus, degraded up to 87% of the tannins in spent coffee grounds as a solid substrate over 32 days. Degradation of tannins was enhanced if potato and dextrose were included. The potential nutritive value of the substrate as animal feed may be improved by this process.