Current mushroom research has concentrated more on nutritional and medicinal aspects. Mushrooms belong to a class of fungi calledBasidiomycetes, which are a source of important enzymes used in making food and medicine. A liquid culture of mycelium and carpophore is commonly used to extract and refine these enzymes. This method, however, is time- and labor consuming and costly.
Cereals can also be used as a solid substrate to culture Basidiomycetes. Rice koji, a product made from rice, can be used as a culture medium to produce Aspergillus oryzae, a source of enzymes such as alpha-, beta-, and glucoamylase and protease. b-amylase is used to make yoghurt, vinegar, and alcohol, whereas protease can be used to produce soy sauce and other food ingredients.