Abstract
The effect of coffee waste compost supplementation on growth, yield, biological efficiency and nutritional composition of oyster mushroom (Pleurotus ostreatus) on wheat straw was evaluated. Four different treatments of substrates were prepared: wheat straw as a control (T0), 25% of coffee waste compost and 75% of wheat straw (T1), 50% of coffee waste compost and 50% of wheat straw (T2), and 75% of coffee waste compost and 25% of wheat straw (T3). The results indicated that the mushroom growth and productivity was significantly increased by moderate coffee waste compost. The shortest spawn running time (15.2 ± 0.3 days), earliest pinhead initiation (20.1 ± 0.4 days), highest number of fruiting bodies (38.6 ± 1.2 per bag), maximum fresh yield (1.84 ± 0.03 kg/bag), and highest biological efficiency (92.4%) were recorded in Treatment T2. Treatment T3, however, exhibited mycelial growth delay, yield reduction and impaired biological efficiency, possibly because of high levels of caffeine and phenolics which caused limitation of fungal growth. The nutritional composition was also analyzed and it was determined that mushrooms grown on coffee waste amended substrates possessed higher protein, crude fiber, ash and fat contents with T2 having the highest crude protein content (27.2%). Based on the results, it can be concluded that moderate supplementation of coffee waste compost has positive effect on the use of the substrate, mushroom productivity and nutritional quality, but extreme amounts of supplementation have a negative effect on the growth of mushrooms. Hence, it is recommended to use 50% coffee waste compost with wheat straw as an effective and sustainable formulation of substrates for mushroom culture of oyster mushrooms.