2.1 Nutritional Benefits It is well recognized that mushroom contains all essential components of a balanced diet. Nutrient content of mushrooms varied depending on the species. In fact, mushroom is rich in digestible essential amino acid, rich protein, vitamins and minerals but low volume of high-quality unsaturated fat and water-soluble carbohydrate [8 addition, it is rich in folic acid, vitamin B complex, phosphorus, potassium, calcium, copper, iron and other essential elements. Mineral content also varied among different species of mushroom. Khan et al. assessed the amount of different minerals in various mushroom species and found 15.4-69 mg Fe, 16 Ca, 11.1-28.8 mg Zn, 14-31.4 mg Mg and 685 1740 mg P per 100 g of dry mushr metabolizable energy content of different mushroom species ranges from 150 Kcal/100g of dry mushroom. The nutritional index of mushrooms ranges from 6 to 31 depending on species which indicates high nutritional value of this food. However, a comparative nutritional index of mushrooms with other foods is presented in Fig. edible mushrooms are low in fat and calories, rich in vitamins and minerals [23], contain more protein than any other food of plant origin.
2.2 Medicinal Benefits Mushrooms are reported to have high medicinal properties. About 6% of edible mushrooms are known to have medicinal properties and can be found in health tonics, tinctures, teas, soups and herbal formulae. Edible mushrooms have been used as important ingredient in the production of certain pharmaceutical products for their medicinal values. Worldwide, Shiitake (Lentinula edodes) and Reishi (Ganoderma lucidum) mushrooms are highly recognized for their medicinal values and said to have antitumor, antiviral properties like anti-HIV and anti-hepatitis B and remove serum cholesterol from the blood stream. Reishi mushroom is known as the ‘mushroom of immortality’. Mushroom contains natural ingredients which are very effective in normalizing blood pressure, lowering blood cholesterol and blood sugar level, protecting the liver, controlling some types of cancers, boosting the body’s immune systems and hence in promoting general fitness.
2.3 Economic Benefits Mushrooms constitute one of the most promising resources for promoting rapid socio-economic development. Cultivation of mushroom is a source of national income as well as a means of poverty alleviation. The production of mushroom creates a large number of direct and indirect employment opportunities in cultivation as well as in marketing activities as a labor-intensive management and offering opportunities for processing enterprises. Mushroom farming needs low capital, low technical knowledge and even in an indoor setting it is possible to cultivate mushroom in a small scale and one can easily get high return with low investment; Women can cultivate mushroom in their homes like rearing poultry with a little capital. Therefore, mushroom cultivation not only empower rural women but also alleviate poverty from the grass-root level.
2.4 Environmental Benefits Mushrooms play an important ecological role in the management of ecosystems. Indirectly, mushroom cultivation is a bioconversion process of organic substances that provides opportunities for the recycling of organic matter thus reducing pollution. Substances used in mushroom cultivation are applied as organic manures to the land after harvesting of mushrooms. Mushroom cultivation is an appropriate technology for the management of agricultural and agro-industrial residues.
3.1 Current Status of Mushroom Production: Mushroom production and consumption are getting popular among the Bangladeshi people. Its production is increasing day by day in Bangladesh as evident by almost four times higher mushroom is produced in 2018-19 compared to 2009-10. An incremental trend of mushroom production was observed over last ten years. Mushroom production and consumption in Bangladesh are increasing through using MDI-developed technologies and low-cost farmer's friendly equipment. Though mushroom production is increased in Bangladesh but could not meet the demand yet. The cost of importing mushrooms in the country is estimated to be BDT 85 to 90 crore per year. The global mushroom production exceeds ten million tons, of which the country contributes only 0.04 million tons. Mushrooms are commercially being cultivated in more than 25 districts of Bangladesh.
3.5 Mushroom Cultivation Method and Season There are several methods of mushroom cultivation like bag cultivation, bottle cultivation, log cultivation etc. in the world. In Bangladesh, bag cultivation method is very popular and extensively practiced throughout the country. Though 5-6 flushes may be harvested from each bag, the first three harvests are very important for commercial production. For each 10 kg of substrate used, depending upon species up to 20 kg of mushroom can be harvested from the first 3-4 flushes [9]. MDI has developed a production calendar for mushroom cultivation in Bangladesh. The growing season of mushrooms are variety and strain-specific; most of the varieties and strains of oyster, shiitake and button mushrooms grow well in winter season whereas milky, reishi, and straw mushrooms are suitable for monsoon. Some strains of oyster and ear mushrooms can be grown throughout the year.
3.7 Economic Performance of Mushroom Mushroom cultivation is highly profitable agribusiness compared to vegetables due to its high price in the market. A study on economics of mushroom revealed that the average gross margin was BDT 38790 and average net return was BDT 22888 with an average BCR 1.55. Cultivation of oyster mushroom on different sawdust showed high BCR which ranged from 3.62-4.25. High BCR (2.24) of mushroom farming as a small-scale family enterprise was reported by Easin et al. The comparative profitability of rice, wheat and mushroom was studied and it indicated that mushroom cultivation is the lucrative one.