CULTIVATION OF EDIBLE OYSTER MUSHROOMS (Pleurotus ostreatus AND Pleurotus sajor-caju) USING SOME SELECTED AGRICULTURAL WASTE SUBSTRATES (COTTON SEED, KHAT LEFT OVER AND SPENT COFFEE GROUND)

Cultivation of edible mushrooms is one of the strategies of production of protein-rich food with the reduction of environmental pollution with full use of all materials in which nothing left as waste. In view of this, an experiment was conducted to evaluate substrates and substrate combination (Cotton seed (CS), khat left over (KL) and spent Coffee Ground (CG)) for oyster mushrooms (Pleurotus ostreatus and Pleurotus sajor-caju) cultivation at Mushroom Research, Production and Training Laboratory of Haramaya University. The results revealed that oyster mushroom showed varying growth performances on different substrate and substrate combinations. Highest total number of effective fruiting bodies (TEFB) (77.50 and 64.33) for Pleurotus ostreatus and Pleurotus sajor-caju respectively, were obtained from 100% CS which taken minimum total time (27.33 day) for both species. Lowest TEFB (21.00 and 15.00) for Pleurotus ostreatus and Pleurotus sajor-caju respectively, were recorded from 100% CG which taken maximum total time (39.04 and 39.37 day) for Pleurotus ostreatus and Pleurotus sajor-caju respectively. For Pleurotus ostreatus, highest (95.18%) and lowest (42.27%) biological efficiency (BE) were recorded on 100% CS and 100% CG respectively. For Pleurotus sajor-caju, highest (93.47%) and lowest (38.97%) BE were recorded on 100% CS and 100% CG respectively. The highest moisture content (MoC) (93.42%) obtained from 100% CS, crude fat (CFa) (1.85%) from 50% CS +50% CG, total ash(7.96%) from 50% CG +50% KL, crude fiber (CFi)(11.95%) from 100% CS, crude protein (CP)(34.61%) from 100% CS and Total carbohydrate (TC)(49.62%) from 100% CS was obtained from Pleurotus ostreatus. On the other hand for the same species the lowest MoC (75.08%) was obtained from 100% CG, CFa (1.76) from 100% CG, TA (6.77%) from 100% KL, CFi (8.68%) from 100% CG, CP(23.27%) from 100% CG and TC (22.80%) from 100% CG was obtained. For Pleurotus sajor-caju, highest MoC(92.84%) from 100% CS, CFa (2%) from 50% KL +50% CG, TA(8.1%) from 100% CS, CFi(11.4%) from 50% CS + 50% CG, CP(32.97%) from 100% CS and TC(46.93%) from 100% CS. The lowest MoC, CFa, TA, CFi, CP and TC were 73.77%, 1.76%, 6.63%, 8.43%, 23.71% and 23.93% respectively, all were obtained from 100% CG except fat (1.76%) obtained from 100% CS. This study revealed that the substrate (CS, KL and CG) and their combinations are more suitable for Pleurotus ostreatus than for Pleurotus sajor-caju in terms growth and nutritional value. From these growth substrates (100% CS) was the most suitable substrate than others. Even though KL and CG alone showed lowest results, their supplementation with CS resulted better result (effective fruiting bodies in terms of number and time), biological efficiency and nutritional value).