Growing mushrooms is one of the ways the ZERI methodology makes value-added products from the waste of several industries. This article explains how valuable shitake mushrooms can be grown on coffee waste to increase farmer's income and use the waste. Similar mushroom cultivation techniques are used for the wastes in sustainable forestry, in the integrated waste management and farming system, in the beer industry, and so on. Ms. Jaramillo has graciously given SCZ permission to post the following article. All photos used on this page are courtesy of Ms. Jaramillo and CENICAFE. First published in 2002 in Spanish, this article was published in English in March 2004.
Carmenza Jaramillo L�pez. Special Project Investigator at CENICAFE (Centro Nacional de Investigaciones de Caf�), Chinchina, Colombia.
This research project develops a complete and effective system to cultivate Shiitake mushrooms with by-products of coffee processing. The process is both an efficient way to utilize biomass that otherwise would be thrown away, and an economically sound business opportunity for thousands of coffee growers. Coffee growers in Colombia are mostly low-income peasants, who lack the income stream of years past, when coffee prices were high and State support was forthcoming.
Under controlled laboratory conditions, CENICAFE (main sponsor of the investigation) has reached levels of Biological Efficiency of up to 75% with the cultivation process that is described in this research paper. Although there are still some steps to be perfected in the area of commercialization, this process, if well implemented, should provide a meaningful source of income and nutritional security for many coffee growers.
The Shiitake mushroom has been called "king" or "monarch" of mushrooms, distinguishing itself as a foodstuff with superior taste and quality. Its scientific name is Lentinula edodes (Berk) Pegler. It has been highlighted as having medicinal properties, and among other constituent elements, it has anti-tumor polysaccharides, anti-virus nucleic acids, active substances that fight cholesterol and substances that inhibit the agglomeration of blood platelets. The Shiitake mushroom has been called nutraceutic because of its nutritional (good source of proteins) and medicinal characteristics, and as a developer of the immunoregulatory system.
Members of Japanese courts centuries ago considered it an aphrodisiac, and history also recalls that emperors in China ate it to delay aging. Other therapeutic properties of Shiitake are the control of arteriosclerosis and the prevention of Cancer. After the well-known mushroom (Agaricus bisporus), Shiitake is the most cultivated of exotic mushrooms in the world. During the last 10 years, the market of A. bisporus has been significantly reduced due to the increase in the production of other edible mushrooms, particularly in the rapid development of shiitake mushroom production.
In Colombia, this species is practically unknown and has been cultivated during the last few years only in its vegetative stage (mycelium), for medical purposes. Its potential in the national market depends heavily on the education that the consumer receives and on the persuasion about its nutritional attributes. Among the most important buyers of this product are the United States of America and Japan, but also some European countries are important potential markets. Interest in this species grew in the western world only after World War II. Today, China and Japan produce more than 1.5 million tons, but the United States and Europe are steadily increasing their production.
Testing duties in the pilot farms done by Cenicafe (Centro Nacional de Investigaciones de Caf�) have been endorsed by the National Federation of Coffee Growers of Colombia and Proexport Colombia.
This was an idea of the Chairman of the ZERI Foundation (Zero Emissions Research Initiative), Gunter Pauli. The Chamber of Commerce of Manizales, headed by Dr. Mario Calderon Rivera, carried out the initial advancements.
On the surface of our planet, around 155 billion metric tons of organic matter are produced through the photosynthetic process each year (Rajarathnam, 1991). However, only a small portion of this organic matter is directly edible by humans and animals. The biggest share of this organic matter is not edible and in many cases transforms into an important source of environmental pollution.
For example, in the flax industry, only 2% of the produced biomass is effectively used, in the brewing industry only 8% of the grain's nutrients are used. Finally, in the palm oil and cellulose industries less than 9% and 30% of the produced biomass are respectively used.
In the coffee industry, only 9.5% of the weight of the fresh material is used for the preparation of the beverage, and 90.5% is left as residue (Calle, 1977).
The cultivation of this mushroom can be done in small-scale and large-scale fashion. Because of the fact that coffee growers have the primary raw material and thus have a comparative advantage for small-scale production, this technical report summarizes the principal features of this production system.
It is important to emphasize the fact that this is a cultivation that demands high levels of asepsis (aseptic conditions) and care in its process, in product selection and market search. The mushroom can be cultivated in altitudes between 1,300 and 1,700 meters above sea level (coffee-growing region), but it is necessary to have the necessary infrastructure and raw materials to develop the process.
Substrates: There is good development and high production only with rich sources of wood. Coffee growers can use the stem of the coffee bush that is obtained after stem cutting process. This material should be transformed into sawdust, then dried and stored immediately after procured.
Infrastructure: Various sites of a coffee farm can be used for small-scale cultivation, such as: abandoned silos, storage rooms, underused houses, etc. The adaptation of these spaces should strive to reach optimal conditions of cleanness, temperature and humidity.
Inputs: Table 1 describes the most important materials and necessary products for a small-scale cultivation.
Procedure: Currently, the establishment of pilot cultivations with a very basic methodology is being encouraged. This procedure consists in:
Preparation of the cultivation means. The objective of this process is to prepare the environment in which the mushrooms will be seeded. For this, the raw materials that will be used are mixed, until the mixture is homogeneous.
The mixture formula is the following:
40% Sawdust of the coffee bush stem
The composition is considered with a dry base. Once the farmer has all the raw material in the farm, it is stored in a covered and dry place. Table 2 describes CENICAFE's tested and recommended formulation. When the material is well mixed (homogeneous), the bags are filled with it. These bags will be the unit of management for the substrate in the following processes:
Bags of polypropylene (16 cms. wide x 50 cms. long, caliber 3) are filled until they reach a weight of 2 kg. Then, they are tied by both sides with 25 cm-long fiber and three drillings are performed in the bags, where the inoculations are to be made. These holes are made with a number 10 punch. The holes are sealed with a piece of court plaster, which permits the exchange of gases in the bag at the moment of sterilization.
One hundred kg. of prepared substrate can fill 50 bags, each one with 2 kg. This parameter helps determine if the mixture has the required moisture content (58-62%) and if it fulfills the required quantities of each raw material.
Thermal treatment. This process is done with an ensemble of containers, and using the vapor from boiling water (double-boiler). This is a very simple system of sterilization using temperatures of 90-100 degrees Celsius, with the water vapor produced by direct heating. The bags should be lined up vertically inside pots of 60cm x 60cm, so that all of the bags have access to the water vapor. After the process is started, it takes 60 minutes until the water boils; then the bags are left during 9 hours sterilizing (2). After these nine hours, the bags are left to cool down during 12 hours inside a lidded pot. Then, they should be taken to a clean and washed room, disinfected with alcohol or Vanodine.
Inoculation. Mycelium is used for the inoculation, that is, commercial seed with a rate of 2% of the weight, with a humid base. Therefore, each 100 kg of substrate, require 2 kg of SPAWN. The inoculation room should be completely clean, washed and disinfected with alcohol or Vanodine, and the inoculation can be performed on a disinfected wooden table, using lighted burners to avoid contamination. The spoon or inoculator should also be disinfected. The person who is to perform the inoculation process should use gloves, mouth protector (muffler), and should not exit the room during the process.
Incubation. Can vary between bags, and takes around 60-70 days, time in which the mycelium covers the bag and it starts changing colors. During this stage, a relative humidity of 85% should be maintained.
During the incubation, checking of the bags should be done at least every three days, in order to detect the following signals of contamination:
- Colors different to white
The bags that exhibit these features should be separated for observation. The contamination can be the result of diverse causes, but the presence of cockroaches, ants, bats, mice, bugs and mosquitoes can spur contamination.
After 50-70 days the mycelium should cover the whole bag. Afterwards, small bumps or bubbles appear that later transform into a sort of cover (thick mycelium). In that same place, some days later, there will be a color change in all bags. This color is called "red-brown mycoderm", which indicates that the shiitake has metabolized the substrate and it is now possible to perform the thermal shock with the bags that have the more homogeneous color and the softest textures.
Fructification. To obtain a homogeneous production, it is necessary to undertake a thermal shock, which consists in subjecting the substrate to a change in temperature, namely lowering the temperature of the substrate to at least 10 degrees Celsius. This is done by placing the bags in a refrigerator during 24 hours, at a temperature between 4 and 8 degrees Celsius. Then, the bags are taken to the fructification room, the sticker plaster is taken off, and the bags are covered with plastic (polypropylene), as the pinhead (first expressions of the body of the mushroom) appears, approximately 8 days later.
During the fructification process, it is necessary to maintain temperatures of 10 to 23 degrees Celsius, humidity of 80-93% and almost total darkness. These conditions are achieved by spraying the floors and walls with cold water or by placing pitchers with water. However, the water used in this irrigation must contain 2ml/L of sodium hypochlorite at 5 %.
As the primordium appears, the plastic bag is taken off. Paper should be placed on the windows in case there is too much luminosity, to maintain semi-darkness. The moment of recollection is when the umbrella (sombrero) begins to open, cutting it carefully with a torsion movement. It is possible to obtain from 3 to 5 harvests per bag. Production in each bag will gradually decrease until there is no more fructification because of degradation in the mycelium. For the second, third, and fourth harvests, the thermal shock is performed by moistening the blocks in water with ice during 24 hours (5).
Post-harvest. The classification and packaging processes depend on the target market of the product. If the product will be sold in the fresh market, the selected mushrooms can be packaged in Styrofoam trays, plastic baskets and polypropylene boxes. If the market is high-volume or destined for export, the mushrooms should be dehydrated.
Biological Efficiency (BE). Enables the assessment of production with the following formula:
BE= (Fresh weight of the produced mushrooms / Weight of the dry substrate) x 100
This formula was developed originally for the mushroom (Agaricus) industry. For a cultivation to be considered profitable, BE must be greater than 50%. CENICAFE has reached levels of BE of 75% in laboratory conditions.
Production and expenses. In order to maintain a continuous production, seeding must be permanent. If the producer wants to generate more than 500 kgs/month, the cultivation system must be modified so that labor use decreases and tasks are facilitated. The size of the bags must be increased and a different thermal procedure must be used for the higher number of bags. The retail price of one kilogram of selected and packed Shiitake is COP$ 16,000, and the production cost using the small-scale methodology is COP$ 10,000, which includes an integral salary for the producer. Changing the closure system and replacing the court plaster with rings and a filter can reduce costs even further.
Commercialization. Edible mushrooms are not a traditional food. Demand has been growing thanks to the escalation of the Asian population and the continuous work of producers to educate consumers. In Colombia, consumption should be encouraged, as it was done 30 years ago with normal mushrooms (Agaricus), which were unknown and now have a market of 3,500 tons a year.
(The authors would like to acknowledge the help of Prof. S.T. Chang, Bacteriologist Fernando Alonso Gomez Cruz, Assistant Humberto Ramirez Quintero, and Industrial Engineer thesis student Ana Luz Arango.)
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