Wood-inhabiting mushrooms can be cultivated in any type of lignocellulosic material, such as straw, sawdust or rice hulls (Victor and Olatomiwa 2013). Pathmashini et al. (2008) showed that the cultivation of the oyster mushroom (Pleurotus ostreatus) on various sawdust types produces different fruiting yields. Sawdust is the most commonly used material for the cultivation of oyster mushrooms and is the preferred medium for commercial production (Oei 2005). Maximum biological efficiency of oyster mushroom cultivation is gained from growth on the sawdust of rubber trees (Pathmashini et al. 2008). It has also been shown that softwood sawdust such as coconut, cashew, mango and rubber are more suitable than hardwood sawdust (Custodio and Cristopher 2004). The availability of raw materials such as sawdust, rice straw, sugarcane wastes are key factors in the choice of agricultural waste for growing mushrooms (Pathmashini et al. 2008). The most commonly and easily cultivated mushrooms in South East Asian countries are oyster mushrooms (Pleurotus), ear mushrooms (Auricularia), and straw mushrooms (Volvariella), Lentinula edodes (shiitake), as well as Lentinus (e.g. Lentinus squarrosulus), Ganoderma, Macrolepiota and “Agrocybe” (i.e., Cyclocybe) spp. (Kwon and Thatithatgoon 2004).
Different types of sawdust are used as the growing medium in tropical areas, depending on the characteristics of the area and the trees available. Rubber tree sawdust is the most popular (Kwon and Thatithatgoon 2004; Klomklung et al. 2012; Nguyen 2004), followed by Acacia auriculiformis (Tapingkae 2005), Mangifera indica (Tong and Rajendra 1992) and Tamarindus indica. For every 1 kg saw dust bag, additions are made of 10 g of calcium carbonate, 50 g of ricebran, 10 g of pumice, 10 ml of molasses, 10 g of flour and 10 g of brewer’s waste. These components are then mixed with water to obtain a water content of 65–70%. Each 800 g of substrate is then tightly packed in a 25.8 cm polypropylene bag and capped with a plastic ring or bottle neck, leaving space to later inoculate with mycelium (Kwon and Thatithatgoon 2004; Stamets 2000; Klomklung et al. 2012; Yamamaka 1997). Each sawdust bag is sealed with a cotton wool plug, covered with newspaper, and tied with a rubber band. The sawdust bags are sterilized at 121 °C for 15 min or at 90–100 °C for 3 h. After the temperature drops to 25 °C, the bags are inoculated with spawn that comprises 10% of the weight of the sawdust bag. Sawdust bags are kept at room temperature (25 °C) at 70–80% humidity to produce fruiting bodies (Klomklung et al. 2012).
When new wild mushrooms are introduced to the market, it is important to conduct fruiting tests. Depending on the type of mushroom, a choice can be made between compost or sawdust media. As a rule of thumb, for woodinhabiting mushrooms (e.g. Lentinula, Auricularia) it is better to use sawdust media in bags, while for soil-inhabiting mushrooms (e.g. Agaricus, Macrolepiota) it is better to use straw compost. For wood-inhabiting mushrooms, protocols adapted from Klomklung et al. (2012) are followed. The surface of sawdust growing bags is inoculated with spawn. The bags are kept in a dark incubation room at the optimum temperature and relative humidity of the particular mushroom. Bags are opened when the mycelium has completely colonized the substrate. The surface of the substrate is scraped slightly with a sterile teaspoon to remove the thin whitish mycelia. The substrate bags are then placed on a shelf and covered with black cloth to allow appropriate ventilation. They are maintained in a growing house at 80–85% relative humidity, and sprayed daily with water until pin heads appear and eventually develop into fruiting bodies. The fruiting bodies are manually harvested, counted and weighed (Klomklung et al. 2012).