Biuletyn Producenta Pieczarek PIECZARKI 1/2018  S. 30-32

What’s next with the standardization of substrate?

Dr Nikodem Sakson, Poznań

I asked the question in the last issue of the Bulletin about the possibility of standardization of a substrate used in growing mushrooms based on the usage of cellulose supplements. It has been three months since then. What has happened during this time that would bring us closer to answering this question? A number of tests have been conducted in laboratory and a process of implementation of Aril KK Premium has been started.

Laboratory tests

A number of tests have been conducted using Petri dishes and containers with 0, 5 kg of substrate in them. (Photo. 1). Previous assumptions that mushroom’s mycelium is going to digest new supplement and that it can be a substantial component in nutrition of Agaricus have been confirmed. Scientific tests from the eighties are being used here. They showed that the main source of energy nutrients for mushrooms is straw (90%), and only the rest (10%) is biomass consisting of dead microorganism that underwent the process of maturation. All of this is a confirmation of the assumption, that digestibility of glucose is improving with the amount of torn fibres in straw, which allow mycelium to gain easier access to cellulose and hemicellulose. All of the above was the basis for further work with this supplement.

Tests during production

Usefulness of new Aril KK Premium and other supplements during a production of mushrooms on phase 2 substrate in a cube was being tested in the area of few square meters in cultivation hall. The results indicate usefulness of the new product. There was a several per cents increase of yield of a very good quality on a very good quality substrate, on which for comparison purposes the yield without the supplement was 28,7 kg/m2. There was a significant increase of quality in second and third flushes, with a very small percentage of fruiting bodies that could be qualified as the weakest (class C). In addition, the fruiting bodies had better colour and their features showed better effects after being processed. Further actions in implementation and testing what kind of results could be achieved on a wider production scale were taken.

Similar tests with Aril KK Premium were conducted in a cultivation hall on a phase III substrate with mushrooms produced for a fresh market. Tests confirmed an achievement of assumed effects like:

• quicker regeneration of the substrate and dissolving of the supplement in substrate few days after being placed on the shelf,
• lower rate of substrate activity, easier control of thermal effects,
• the beginning of the yield started a day earlier,
• better spread of fruiting bodies,
• significant increase in the quality of fruiting bodies and increase in yield in second and third flush,

First implementations

At the time of publishing of this article yield in full six week cycle wasn’t conducted. That is why only occurrences accompanying production with Aril KK Premium until the first flush can be pointed out. They confirm the changes that were mentioned in parts 1-3 of this article. Further observations can be made:

• The substrate has to be properly placed on the shelf. If it is not compact enough, it is easy to cause overflowing of the substrate, which may result in its local rotting. It is a result of greater water capacity of the supplement. It is also harder to maintain the temperature of the substrate up to the moment of putting water into it. Pillow effect. On the other hand, if the substrate is compacted too much the result is inability of putting water into it, which makes the cooling process harder and excessive humidity in places of contact between the substrate and casing soil.
• The supplement has to be mixed very carefully with the substrate. Assumption that maximum amount of supplement should not be higher than 20% of substrate’s volume is being verified. Only in this case the effect of surrounding of a straw blade by a supplement can be achieved, without creating places where there is only supplement, far away from the mycelium, which makes it harder to transfer, especially taking into consideration its high humidity.
• Thermal effect is still present during production on phase 3 substrate. Aril KK Premium supplement makes it easier to control, because of lower protein content. The results of using this supplement are achieved only when substrate’s temperature is no higher than 25-27°C before the shock. It can be done by lowering the temperature early enough, at the time of beginning of putting water into the substrate and raising the temperature of cold substrates, for example when it is 23°C, and with addition to intensive movement of the air to nullify the temperature difference between the air and the substrate.
• it can be assumed that. when mushrooms have bigger nutrition resources, it is easier to spread the flush. Tendencies of spontaneous spreading out can be observed, in the same conditions as during binding without the supplement. The first buds appear a day earlier, and fruiting bodies have significantly better quality.

Nevertheless the main goal is to increase the yield in the second and the third flush with a significant improvement of quality. One has to wait for the full assessment.

Usage of Aril KK Premium is in the implementation phase. There is not enough data about the supplement’s effects during the process of mushroom production. As an innovation it can be divided, which means that it can be implemented gradually, starting with smaller dosages and only in some parts of the crop.

Polska wersja artykułu / Polish version

Biuletyn producenta Pieczarek PIECZARKI 4/2017  S. 32-36

Could supplements make standardisation of substrate possible?

dr Nikodem Sakson, Poznań

Changing quality of substrate is a fact. There are many reasons for this. One of them is that methods of controlling the process of compost production are not precise enough. You can find my propositions of changing this status quo in the last issue of Bulletin. Nevertheless solving the problem of producing substrate of stable quality can be resolved by actions taken in compost yards. Lack of changes in the quality of compost is the reason of searching for solutions allowing for standardisation of substrate on mushroom farms. One of these solutions could be usage of new generation substrate supplements that are based on high content of easily available cellulose and hemicellulose. They are called cellulose supplements for substrate.

Mushrooms intake of nutrients from compost takes place in two forms. The first is by dead microorganism that is in compost after its maturity phase, the other is left over degraded straw and supplements.

To improve the quality of substrate different supplements are used. They can be divided into two basic groups:

1. Compost supplements. Their role is to maintain desirable ratio of carbon to nitrogen and to maintain availability of carbohydrates and nitrogen during composting process. For further information on this topic read my article in Bulletin no. 3/17;
2. Substrate supplements, for differentiation called ‘feeding supplements’. Feeding supplements used nowadays do not allow for full standardisation of substrate. The reason for this is that when deficiency of nutrients is high enough, maximum dosages of feeding supplements cannot reduce it. Those limitations are the result of the way feeding supplements influence thermal effects. Limited, in given time, high assimilation of nutrients that the feeding supplements are containing is also the reason. A new formula of supplements is based on ideas taken from complete feed for animals. It means that the content and availability of nutrients can allow for mycelium to feed on them the same way as on compost. Hence the feeding supplements have to meet the following criteria:

• They have to absorb water (fully moisturize itself) during few hours since introduction to substrate.
• The transfer of nutrients from feeding supplement to mycelium should be 50% of their content during 72 hours.

The ratio of nutrients and their treatment is based on scientific researches that are the basis of modern biotechnology. Raw materials from grass fulfil these criteria. They undergo the processes that allow for their easier availability (as in compost).

What goals can be achieved when using feeding supplements that are rich in cellulose?

1. Reaching projected volume of yield, independently of the quality of substrate. The dosage can be as high as several or even over a dozen per cent of substrate’s weight. What is expected is the increase in yield of the second and third flushes with maintaining of high volume weight of fruiting bodies in all flushes and maintaining of previous spread in consequential flushes.
2. Elimination of thermal effect after placing on the shelf and during the growth, mainly between the first and the second flushes. In case of low activity, starch supplements could be introduced.
3. Elimination of threats as green mould in the third flush by using feeding supplements to casing soil, that would be fully assimilated by mycelium until the end of shock and are not colonised by green mould after lowering of pH in casing soil during the third flush.

Cellulose supplements introduced to substrate are used by Agaricus as a source of glucose in the process of external enzymatic degradation. This process is most effective in temperatures of 23-27⁰ C, so in temperatures in which the growth of mycelium is the quickest. Exceeding temperature of 30⁰ C stops the process nearly completely. Controlling the temperature may be easier because of high water capacity of these supplements. As a result thermal effect is eliminated. This effect was the main reason of reduction of possibilities of using high dosages of available nowadays supplements with high protein content. They are the cause of increase of temperatures, which obstructs usage of cellulose and hemicellulose it is containing. Usage of which decreases when the temperature of substrate is higher than 27⁰ C. Initial increase of substrate’s temperature after being placed on the shelf can be fully controlled by using higher dosages of water. Higher water capacity of substrate that is enriched that way makes controlling the temperature easier. The beginning of increase of temperature signifies the moment of starting of assimilation of glucose from feeding supplement introduced into substrate.

Additional factor that can stabilise the yield is usage of the feeding supplement in the casing soil. The requirements are similar as to using feeding supplements in the substrate. Recommendations which are to be followed to effectively use supplement to Nutrigain casing soil can be an example of this. After introduction to the casing soil with the last two litres of water, it is to be covered by micro perforated foil. The air flow should be reduced, so the temperature of casing soil is high enough. Covering it allows high concentration of carbon dioxide to occur, which benefits enzymatic activity of the mycelium.

Goals of using cellulose feeding supplements that were mentioned above are to be reached without the raise of cost (or in very small increase), because raw materials used in their productions are cheaper, and also the cultivation process can be done on a smaller amount of substrate.

If the compost producer doesn’t provide services of putting the feeding supplement into the compost projected goals can be achieved by self-determination of the dose of feeding supplement and putting it into the substrate in a mushroom farm during placement of the shelves. In smaller companies the dosages could be established based on the individual check of the quality of compost and will take into consideration using excessive amount of feeding supplements over the projected yield volume. Bigger mushrooms farms can establish the dosages and recipes based on the actual needs, using mobile NIR spectrometer that allows checking substrate’s quality during loading.

Is this solution a real one?

Using cellulose supplements seems to be a real solution of problems with standardisation of quality of substrate, but is it really? And to what extent? Also can it be implemented in all kinds of substrates that are produced in Poland? To answer those questions several tests in production context have to be conducted. Results of first tests show, that there is a high probability of achieving this goal.

One can assume this solution has potential for real changes, because it is based on solid scientific knowledge.

For mushrooms the straw in compost is the basic source of glucose, assimilated from cellulose and hemicellulose in it. Their placement is the problem. They are in cell walls surrounded by lignin, which is not digested effectively by Agaricus’ enzymes (in contrast to Pleurotus, which has this ability and so can be grown on straw itself). For mushrooms to have access to glucose straw has to be submitted to the process of composting or to be mechanically teared. It is shown on illustration number 1.

Raw materials used in production of feeding supplements are usually wastes occurring during agricultural production or are cheaper than wheat seeds or soya. But they need additional processing: grinding and tearing of cell membranes (extrusion, expanding or micronization). The process of tearing the membranes allows for sanitization of supplement (getting rid of potentially harmful microflora), at the same time those processes have to be done properly, as not to allow for substances that limit mycelium’s activity to occur.

Processing of raw materials causes significant increase in feed supplement’s water volume and easier humidity and as a result, increases in assimilation of nutrients that are in it. Giving mushrooms source of nitrogen, which is obtained by enzymatic decomposition of proteins, is significant too. Cellulose feeding supplements have got some amount of proteins and other components essential for mushroom’s life. Those contents are located in dead cytoplasm of cells of plants used as raw material for their production. There are also micro- and macro elements essential for mushrooms life in feeding supplements, but in case of lack of them they can be supplemented using TOP Vital. Its composition can be matched according to current needs.

Achieving positive results during conducted test will depend on development of technology of using high dosages of cellulose feeding supplements. On one hand the development should influence placing and correct mixing with substrate, on the other hand – balancing the dosages of water.

Other tests are also conducted on dividing the dosages of feeding supplement, when it is put in a part of phase II substrate. However using this solution is limited because of the humidity of the compost. Dosages that are too high may lead to deficit of water, at the same time limiting its usefulness. Feeding supplement implementing goals, that were mentioned above is produces by company Aril. (Photo 1 and 2)

Developing technology, which would allow increase in high quality yield and reduction of production costs, are significant factors in maintaining competitiveness of mushrooms produced in Poland.

Photo. 1. New product

Photo. 2. Previous product

Illustration. 1 Processed lignin-cellulose fibre

Source: based on: L. Kratky, T. Jirout, Biomass size reduction machines for enhancing biogas

production, „Chemical Engineering&Technology” 2011 no. 34, p. 391-399. Cited in: Kamil Witaszek, Agnieszka Anna Pilarska, Krzysztof Pilarski, Wybrane metody wstępnej obróbki surowców roślinnych stosowanych do produkcji biogazu, „Ekonomia i Środowisko” 2 (53), 2015, p.130-144

Polska wersja artykułu / Polish version