MUSHROOM CULTIVATION 11 1988.So0nn or myc es and Chan als onmental po tant.In addition that are abundantly availabl n rural and urba impacts on long-term o Therefore,the significant impact of applied mushroom biology on human welfare has been named a"nongreen revolution"(Chang.1999). Mushro m Biore nediation This component of applied mushroon of mushroom mycelium.Environmental contamination can be ameliorated by the application of mushroom mycelial technologies.For example: n the po ofpent substrates/com posts in order to eliminate the pollution problems (Beyer,2005:Noble 2005).One of the most intriguing opportunities offere by mu a in the area of biocon on the exp tation o released into the environments cinogeni ence of hu 2.The use of fungi/mushroom repair or restore the weakened or damaged biosystems of environment The proce the se lective use of mus esticides to insect pests.Mycorestoration recognizes the primary role fungi/mushrooms play in determining the balance of biological populations 1.4 MUSHROOM CULTIVATION Mushroom cultivation is both a science and an art.The science is developed research e art is perfected through consonance with those common example.there is a vegetative growth phase,when the mycelia row profusel and a reproductive (fruiting)growth phase,when the umbrella-like body that
MUSHROOM CULTIVATION 11 processing biomass wastes (e.g., soybean wastes using submerged culture) into fungal protein (Buswell and Chang 1994) or “mycomeat” (Miles and Chang 1988). Soybean waste materials (slurries) are generated in large quantities during the processing of soybean milk and “tofu” (bean curd), which are popular foods in many countries now and are, in some places, discarded without treatment, thereby constituting an environmental pollutant. In addition, mushrooms and their mycelia can provide nutriceutical and pharmaceutical products. As outlined above, by blending the advances in basic biological knowledge with that of practical technology, a mushroom-related industry based on utilization of the lignocellulosic waste materials that are abundantly available in rural and urban areas can have positive global impacts on long-term food nutrition, health, environmental conservation and regeneration, and economic and social change. Therefore, the significant impact of applied mushroom biology on human welfare has been named a “nongreen revolution” (Chang, 1999). 1.3.3.2 Mushroom Bioremediation This component of applied mushroom biology deals mainly with the aspects of benefits to the earth from the activities of mushroom mycelium. Environmental contamination can be ameliorated by the application of mushroom mycelial technologies. For example: 1. The use of bioconversion processes to transform the polluting substances into valuable foodstuffs, for example, the proper treatment and reutilization of spent substrates/composts in order to eliminate the pollution problems (Beyer, 2005; Noble, 2005). One of the most intriguing opportunities offered by mushroom mycelia in the area of bioconversion is the exploitation of their ability to degrade pollutants, many of which are highly carcinogenic, released into the environment as a consequence of human activity. 2. The use of fungi/mushroom mycelia as tools for healing soil, what Stamets (2005) called “mycorestoration,” which is the use of fungi/mushrooms to repair or restore the weakened or damaged biosystems of environment. The processes of mycorestoration include the selective use of mushrooms for mycofiltration to filter water, mycoforestry to enact ecoforestry policy, mycoremediation to denature toxic wastes, and mycopesticides to control insect pests. Mycorestoration recognizes the primary role fungi/mushrooms play in determining the balance of biological populations. 1.4 MUSHROOM CULTIVATION Mushroom cultivation is both a science and an art. The science is developed through research; the art is perfected through curiosity and practical experience. Mushroom growth dynamics involve some technological elements that are in consonance with those exhibited by our common agricultural crop plants. For example, there is a vegetative growth phase, when the mycelia grow profusely, and a reproductive (fruiting) growth phase, when the umbrella-like body that
12 OVERVIEW OF MUSHROOM CULTIVATION AND UTILIZATION AS FUNCTIONAL FOODS Triggers Vegetative Phase Reproductive Phase rature」 phase are usually regulated by environmental factors. same principle in mushroom production.After the vegetative (mycelial)phase the inductio This is the time the mycel Igrowth tips should e retarded b lowering temperature.can trigger fruiting (Figure 1.6). 1.4.1 Major Phases of Mushroom Cultivation ion indeed it is no cise procedures.The major practical steps/sements of mushroom cultivation lection of a cceptable mush n species (2)secretion o good-quality t(5 lial (s st spawn. ent of f and mushroom develoment and (careful harvesting of mushrooms(Chang and Chiu,1992;Chang 1998).If you ignore h could to a substantially reduced mus 1.Before any decision to cultivate a particular mushroom is made.it is important to determine if that species possesses organoleptic qualities
12 OVERVIEW OF MUSHROOM CULTIVATION AND UTILIZATION AS FUNCTIONAL FOODS Triggers Vegetative Phase Reproductive Phase CO2 O2 Temperature Light Figure 1.6 Two major phases of mushroom growth and development: vegetative and reproductive. The triggers for the transition from the vegetative phase to the reproductive phase are usually regulated by environmental factors. we call mushroom develops. In agricultural plants (e.g., sunflowers), when the plants switch from vegetative growth to reproductive growth, retarding tips for further growth (elongation) is an obvious phenomenon of maturity. It is the same principle in mushroom production. After the vegetative (mycelial) phase has reached maturity, what the mushroom farmer needs next is the induction of fruiting. This is the time the mycelial growth tips should be retarded by regulating the environmental factors. These factors, generally called “triggers” or “environmental shocks,” such as switching on the light, providing fresh air, and lowering temperature, can trigger fruiting (Figure 1.6). 1.4.1 Major Phases of Mushroom Cultivation Mushroom farming is a complex business that requires precision. Indeed, it is not as simple as what some people often loosely stipulate. It calls for adherence to precise procedures. The major practical steps/segments of mushroom cultivation are (1) selection of an acceptable mushroom species, (2) secretion of a good-quality fruiting culture, (3) development of robust spawn, (4) preparation of selective substrate/compost, (5) care of mycelial (spawn) running, (6) management of fruiting and mushroom development, and (7) careful harvesting of mushrooms (Chang and Chiu, 1992; Chang 1998). If you ignore one critical step/segment, you are inviting trouble, which could lead to a substantially reduced mushroom crop yield and mushroom marketing value: 1. Before any decision to cultivate a particular mushroom is made, it is important to determine if that species possesses organoleptic qualities
MUSHROOM CULTIVATION 13 nts for svstems of mechanical control. 2.A"fruiting culture"is defined as a culture with the genetic capacity to form fruiting bodies under suitable growth conditions.The stock culture selected should be acceptable in terms of yield,flavor,texture,fruiting time,and so 3. of a fruiting cuure has growna tivation is called the"mushroom spawn."Failure to achieve satisfactor harvest may often be traced to unsatisfactory spawn used.Consideratio must alsc given to the nature of the spawn su 4.While a sterile substrate free from all competitive microorganisms is the ideal medium for cultivating edible mushrooms.systems involving such es for culti e mushrooms nor 1。 must be rich in e ntial nutrients in forms which are readily available to the mushroomand be fr of toxic ubstances that inhibit growth o f the spawr t are im sical face 5.Followin d anisms.Afte the compost has cooled,the spawn may be broadcast over the bed surface and the ed d wn hrmly aga con which from the sn Good mycelial growth is essential for mushroom production. 6.Under suitable environmental conditions.which may differ from thos adopted for primordial formation occurs and then is fol lowe alley the proc led"o eappearance of mushroom ecies and c es and market value ges depending upon the 1.4.2 Cultivation of Several Selected Mushrooms The cultivation of edible mushrooms can be divided into two maior stages.The first stage involves the preparation of the fruiting culture,stock culture.mother spawn,and planting spawn,while the second stage entails the preparation of
MUSHROOM CULTIVATION 13 acceptable to the indigenous population or to the international market, if suitable substrates for cultivation are plentiful, and if environmental requirements for growth and fruiting can be met without excessively costly systems of mechanical control. 2. A “fruiting culture” is defined as a culture with the genetic capacity to form fruiting bodies under suitable growth conditions. The stock culture selected should be acceptable in terms of yield, flavor, texture, fruiting time, and so on. 3. A medium through which the mycelium of a fruiting culture has grown and which serves as the inoculum of “seed” for the substrate in mushroom cultivation is called the “mushroom spawn.” Failure to achieve a satisfactory harvest may often be traced to unsatisfactory spawn used. Consideration must also be given to the nature of the spawn substrate since this influences rapidity of growth in the spawn medium as well as the rate of mycelial growth and filling of the beds following inoculation. 4. While a sterile substrate free from all competitive microorganisms is the ideal medium for cultivating edible mushrooms, systems involving such strict hygiene are generally too costly and impractical to operate on a large scale. Substrates for cultivating edible mushrooms normally require varying degrees of pretreatment in order to promote growth of the mushroom mycelium to the practical exclusion of other microorganisms. The substrate must be rich in essential nutrients in forms which are readily available to the mushroom and be free of toxic substances that inhibit growth of the spawn. Moisture content, pH, and good gaseous exchange between the substrate and the surrounding environment are important physical factors to consider. 5. Following composting, the substrate is placed in beds where it is generally pasteurized by steam to kill off potential competitive microorganisms. After the compost has cooled, the spawn may be broadcast over the bed surface and then pressed down firmly against the substrate to ensure good contact or inserted 2–2.5 cm deep into the substrate. Spawn running is the phase during which mycelium grows from the spawn and permeates into the substrate. Good mycelial growth is essential for mushroom production. 6. Under suitable environmental conditions, which may differ from those adopted for spawn running, primordial formation occurs and then is followed by the production of fruiting bodies. The appearance of mushrooms normally occurs in rhythmic cycles called “flushes.” 7. Harvesting is carried out at different maturation stages depending upon the species and consumer preferences and market value. 1.4.2 Cultivation of Several Selected Mushrooms The cultivation of edible mushrooms can be divided into two major stages. The first stage involves the preparation of the fruiting culture, stock culture, mother spawn, and planting spawn, while the second stage entails the preparation of
14 OVERVIEW OF MUSHROOM CULTIVATION AND UTILIZATION AS FUNCTIONAL FOODS the growth substrates for mushroom cultivation.Cultivation conditions for a few selected mushroom species are briefly described in the following sections. Cultiv Compo nd Ha itl 197:Kaul and Dhar.2007).In phase I of the process ( ing) locally available raw materials are arranged into piles that are periodically turned nitial breakdown of the raw ingredients bym sms tak liahle dark h n in canahle of holdi There is normally a strong smell of ammonia.Phase II (indoor fermentation)is rion,when undesirable organisms are removed from the compost.Ih upon the nature of thecom ammonia level drops below 10PPM.Following phase II composting.the substrate is cooled to 30 for. ga cus bitorquis and to 25C for A.bisporus for spawning Th production of phase III compost is phase II compost spawn run in a bulk tunnel and ready for casing when delivered to the grower If the phase oped int bulk phase I and IV dep nd a lot on the quality of phase I and II es Pha Ion shelves produces an average of crops per year.growers using oed an average of crops 2 crops per year(Dew i edible mushroom,but since 2002 it has become the world number one cultivated tCgangaodl8cgoaahcticsubanieloes ang and 1.Biological Nature Lentinula edodes is a heterothallic mushroom.Its sex uality is controlled by two mating factors.A and B.with multiple alleles.and Its life vcle starts the germination of basidios 、After selected mat ins between two compatibility erminative mvcelium.the dikarvon mvcelium or fruit ing cuture is established.From the fruiting culture.the mothe n the discharged and its life cycle is completed
14 OVERVIEW OF MUSHROOM CULTIVATION AND UTILIZATION AS FUNCTIONAL FOODS the growth substrates for mushroom cultivation. Cultivation conditions for a few selected mushroom species are briefly described in the following sections. 1.4.2.1 Cultivation of Agaricus Composting is prepared in accordance with well-documented commercial procedures(van Griensven, 1988; Chang and Hayes, 1978; Kaul and Dhar, 2007). In phase I of the process (outdoor composting), locally available raw materials are arranged into piles that are periodically turned and watered. The initial breakdown of the raw ingredients by microorganisms takes place in phase I. This phase is usually complete within 9–12 days, when the materials have become pliable, dark brown in color, and capable of holding water. There is normally a strong smell of ammonia. Phase II (indoor fermentation) is pasteurization, when undesirable organisms are removed from the compost. This is carried out in a steaming room where the air temperature is held at 60Ž C for at least 4 hours. The temperature is then lowered to 50Ž C for 8–72 hours depending upon the nature of the compost. Carbon dioxide is maintained at 1.5–2% and the ammonia level drops below 10 PPM. Following phase II composting, the substrate is cooled to 30Ž C for Agaricus bitorquis and to 25Ž C for A. bisporus for spawning. Production of phase III or IV composts for growing Agaricus mushrooms has been an advanced technological development in recent years in Western countries. The production of phase III compost is phase II compost spawn run in a bulk tunnel and ready for casing when delivered to the grower. If the phase III compost is then cased and spawn developed into the casing layer before dispatching to the growing unit or delivering to growers, it is named as phase IV compost. The successes of bulk phase III and IV depend a lot on the quality of phase I and II processes. Phase II on shelves produces an average of 4.1 crops per year. Since 1999, growers using Phase III production enjoyed an average of 7.1 crops per year. In recent years, phase IV can generate 10–12 crops per year (Dewhurst, 2002; Lemmers, 2003). 1.4.2.2 Cultivation of Lentinula edodes Lentinula edodes (xiang gu in Chinese and shiitake in Japanese) was the second most important cultivated edible mushroom, but since 2002 it has become the world number one cultivated mushroom. It can be cultivated either on wood log or on synthetic substrate logs (Quimio et al., 1990; Stamets, 2000; Chang and Miles, 2004). 1. Biological Nature Lentinula edodes is a heterothallic mushroom. Its sexuality is controlled by two mating factors, A and B, with multiple alleles, and therefore, its life history is a tetrapolar or bifactorial mating system (Chang and Miles, 1984). Its life cycle starts the germination of basidiospores. After selected mating between two compatibility germinative mycelium, the dikaryon mycelium or fruiting culture is established. From the fruiting culture, the stock culture, mother spawn, and commercially planting spawn can be made. When the spawn is planted on a suitable substrate, under good climatic conditions the fruiting bodies of the mushroom are developed. Then when the mature stage is reached, the spores are discharged and its life cycle is completed
MUSHROOM CULTIVATION 15 0.148% y speaking the carbon-nitroge ratio in substrate should be in the range of 25:1-40:1 in the vegetative growth the nitrogen source ve phas The optimum temperature of spore germination is 22-26C.The temperature C,but the optimum temper ture the initial and dev ature of fruitin mation is in the of10-20°C and the ont um temperature of fructification for most varieties of the mushroom is about 15C.Some varieties can fruit in higher temperatures (e.g. 23 hese high-te faster ha ened and become flat-grade mushrooms which are conside to be low quality.The g is about 5.0-5 o the substrate used in making the mushro 2.Culture Media and Preparation The mushroom can grow on a variety of cu ent agar form at d synthetic.de d tim are not commonly used for routine pur ced potato,200 g:de powde agar (or agar bars). (b)Pro Peeled potatos vashed.weighed.and are boiled in a cas (around 15 minutes).The potatos are removed and water is added to the broth to ke exactly broth is return to th serole,and de elted The hot solution is then clean fat ho tles.For pure or stock cultures,the test tubes are filled with at least 10mLo tion.The ttles or test tubes are plugged with cottonwoo mnese can be use ce mycelial plug Examples of the different formulas for spawn substrates ar re described belo awn.( gypsum lim ane hagasse d0c sawdust 38 wheat hran 206 gar s and v 1.Planting spawn:A number of materials,mostly agricultural and forest wastes can be used to prepare mushroom planting spawn.Three of them are given here
MUSHROOM CULTIVATION 15 Lentinula edodes is kind of wood rot fungus. In nature, it grows on dead tree trunks or stumps. In general, the wood for the mushroom growth consists of crude protein 0.38%, fat 4.5%, soluble sugar 0.56%, total nitrogen 0.148%, cellulose 52.7%, lignin 18.09%, and ash 0.56%. Generally speaking, the carbon–nitrogen ratio in substrate should be in the range of 25 : 1–40 : 1 in the vegetative growth stage and from 40 : 1 to 73 : 1 in the reproductive stage. If the nitrogen source is too rich in the reproductive phase, fruiting bodies of the mushroom are usually not formed and developed. The optimum temperature of spore germination is 22–26Ž C. The temperature for mycelial growth ranges from 5 to 35Ž C, but the optimum temperature is 23–25Ž C. Generally speaking, L. edodes belongs to low-temperature mushrooms; the initial and development temperature of fruiting body formation is in the range of 10–20Ž C and the optimum temperature of fructification for most varieties of the mushroom is about 15Ž C. Some varieties can fruit in higher temperatures (e.g., 20–23Ž C). These high-temperature mushrooms usually grow faster and have a bigger and thinner cap (pileus) and a thin and long stalk (stipe). Their fruiting bodies are easily opened and become flat-grade mushrooms, which are considered to be low quality. The optimum pH of the substrate used in making the mushroom bag/log is about 5.0–5.5. 2. Culture Media and Preparation The mushroom can grow on a variety of culture media and on different agar formulations, both natural and synthetic, depending on the purpose of the cultivation. Synthetic media are often expensive and time consuming in preparation; hence they are not commonly used for routine purposes. The potato dextrose agar, or PDA, is the simplest and the most popular medium for growing the mycelium of the mushroom. It is prepared as follows: (a) Ingredients: Diced potato, 200 g; dextrose (or ordinary white cane sugar), 20 g; powdered agar (or agar bars), 20 g; and distilled water (or tap water), 1 L. (b) Procedure: Peeled potatos are washed, weighed, and cut into cubes. They are boiled in a casserole with at least 1 L of water until they become soft (around 15 minutes). The potatos are removed and water is added to the broth to make exactly 1 L. The broth is returned to the casserole, and dextrose and the agar are added. The solution is heated and stirred occasionally until the agar is melted. The hot solution is then poured into clean flat bottles. For pure or stock cultures, the test tubes are filled with at least 10 mL of liquid agar solution. The bottles or test tubes are plugged with cottonwool. When petri dishes are available, these can be used to produce mycelial plugs for inoculation of mother spawn. Examples of the different formulas for spawn substrates are described below. Mother grain spawn: (i) Wheat/rye grain C 1.5% gypsum or slaked lime. (ii) Cotton seed hull 40%, sawdust 38%, wheat bran 20%, sugar 1%, and gypsum 1%. (iii) Sugar cane bagasse 40%, sawdust 38%, wheat bran 20%, sugar 1%, and gypsum 1%. Planting spawn: A number of materials, mostly agricultural and forest wastes, can be used to prepare mushroom planting spawn. Three of them are given here