Effect of supplementation of rice straw with biogas residual slurry manure on the yield, protein and mineral contents of oyster mushroom

Popularity of oyster mushroom is increasing for its ease of cultivation, high yield potential as well as its high nutritional value. Laboratory experimentation followed by farm trial with a typical oyster mushroom Pleurotus sajor caju revealed that the yield potential of these mushrooms can be increased significantly when grown on a lignocellulosic crop residue-rice straw supplemented with biogas residual slurry manure in 1:1 ratio as substrate. Residual slurry manures obtained from biogas plants utilising either cattle dung, poultry litter, jute caddis or municipal solid waste as substrates for biogas production were all effective in increasing the yield of Pleurotus sajor caju significantly although to different extents. Disinfection of straw and manure by means of 0.1% KMnO4 plus 2% formalin solution in hot water caused 42.6% increase in yield of Pleurotus sajor caju over control, i.e., when disinfection done with hot water. In addition to increased yield, the above treatments caused significant increase in protein content, reduction in carbohydrate and increase in essential mineral nutrients in mushroom sporophores. Thus, it is concluded from the study that supplementation of rice straw with biogas residual slurry manure has strong impact in improving the yield potential, protein and mineral nutrient contents of Pleurotus sajor caju mushroom in Indian subcontinent or similar climatic conditions. (C) 2003 Elsevier B.V. All rights reserved.