Cultivation of Pleurotus mushrooms on Brazilian coffee husk and effects of caffeine and tannic acid

摘要

The possibility of using the total coffee residue (husks) obtained from the Brazilian coffee industry as substrate for cultivation of Pleurotus mushroom and degradation of caffeine and phenolic compounds present in this residue were studied. Eight strains of P. ostreatus and two strains of P. sajor-caju were tested on a medium prepared from aqueous extract of coffee husk and agar. Based on the best mycelial growth and biomass production in plate, the strain P. ostreatus LPB 09 was selected for further studies. The first fructification occurred 20 days after inoculation, and the biological efficiency reached about 96% after 60 days. It was found that fruiting bodies accumulated 0.157-mg/g caffeine on a dry weight basis. After cultivation, the content of caffeine and phenolic compounds in the husk was reduced at 60.6% and 79.1%, respectively. The results indicated the feasibility of using coffee husk without any pretreatment for the cultivation of Pleurotus. We propose that after cultivation, the residue might be useful for feeding of ruminant as several toxic compounds decreased, while the protein concentration increased (9.62%).