Cultivated mushrooms are an important food source for many people around the world, with global production estimated at over 10 million tons per year (Food and Agriculture Organization of the United Nations 2014). Over two thirds of the production of edible mushrooms are harvested in mainland China, where mushrooms form a more traditional role in food and medicine than they do in many Western countries, and where they provide a living for over 25 million mushroom farmers (Zhang et al. 2014b). The most important edible mushroom genus grown commercially is Agaricus (mainly Agaricus bisporus, the button mushroom), which makes up about 30% of the global market (Royse 2014). Other important edible genera include Pleurotus (5–۶ species of oyster mushrooms that are cultivated commercially), Lentinula (shiitake), Auricularia (3–۴ species of woodear mushrooms), Flammulina (enoki), and Volvariella (paddy straw). Edible mushroom production is dominated by a few species where the technology for large-scale industrial cultivation has been optimized (Chang and Miles 2004), but in many countries large numbers of small-scale farms also exist, and there are increasing attempts to domesticate local wild mushrooms for production purposes (Mwai and Muchane 2016). Cultivated mushrooms are saprophytes which grow by degrading natural lignocellulosic substrates, which are commonly available in large volumes as agricultural or industrial byproducts. The methods for commercial cultivation of mushrooms on these substrates can be divided into three broad groups. The first group includes cultivation of many wooddegrading mushrooms that were traditionally grown on wood logs or harvested from trees. Some of these, such as Lentinula, are now grown on artificial logs of compacted, sterilized sawdust, while others, such as Flammulina, Pholiota (nameko), or Auricularia are cultivated on a partly composted mixture of sawdust and other components (bran, straw, corncobs), which is sterilized at high temperature (121 °C) before inoculation with mycelium (Chang and Miles 2004; Sanchez 2010). Because of the rigorous sterilization process, these mushrooms are essentially grown in axenic culture. The second group of cultivation methods either uses uncomposted substrates directly, or uses partially composted substrates that have not been subjected to a rigorous sterilization process. This includes methods commonly used for Pleurotus and Volvariella species, though Pleurotusis also sometimes grown on sterilized sawdust substrates. These are fast-growing and adaptable genera capable of rapid bioconversion of a broad range of substrates (e.g., rice straw, bagasse, cornstalks, waste cotton, stalks, and leaves of bananas (Chang and Miles 2004; Thongklang and Luangharn 2016). The substrates are usually not sterilized before inoculation, though a pasteurization step may be included in the process, and the mushrooms therefore grow in competition with other microorganisms on the substrate. The most industrially complex process is the cultivation of Agaricus, which is grown on a pasteurized straw-based compost which requires lengthy preparation, but allows selective growth of the Agaricus mycelium over competitor organisms.