ECOLOGICALLY SAFE UTILIZATION OF ORGANIC WASTES AND TECHNOLOGY OF PRODUCTION OF THE FUNGUS PLEUROTUS OSTREATUS (THE OYSTER MUSHROOM)

Abstract

Background. Organic cellulose-containing wastes are represented by various substrates with diverse physicochemichal properties suitable as feedstock for obtaining new products, e.g. mycelium and fruit bodies of edible mushrooms. Industrial mushroom cultivation based on utilization of different kinds of organic wastes is one of the perspective directions in biotechnology and agriculture.
 Improving the nutrient value of substrates and increasing the reliability of mushroom culture is possible at expense of utilizing nutrient supplies originated as wastes of another industry, for example, the use of sparging grain, which is the major waste of brewery. Wet sparging grain has humidity of 70-80%, and contains in average more than 20% of dry residues with high protein level (12-15%), which is approximately three times higher its content than in barley. For that reason, as a supplement to nutrient media and substrates, for rearing mycelium and fruit bodies of the fungus Pleurotus ostreatus, we propose the use of the brewers’ industry, the wet sparging grain.
 Purpose. Evaluation of the possibility of utilising the wastes of agriculture and brewery, for growing mycelium and fruit bodies of the edible mushroom Pleurotus ostreatus.
 Materials and methods. The study was carried out in the years 2017-2021 in the laboratory of the Department of biology and technology of living systems at L.N. Tolstoy TSPU. The research objects were the fungus Pleurotus ostreatus, wet sparging grain, and various agricultural wastes (wheat straw, buckwheat chuff, sunflower seed husk).
 For mycelium extraction, we used the method of seeding superficially sterilized pieces of fruit bodies onto the hard sterile agarized nutrient medium in the Petri dishes. For obtaining the master culture of mycelium and fruit bodies of the fungus Pleurotus ostreatus we utilized substrates of various composition containing the sparging grain and agricultural wastes. The data obtained were statistically processed and analysed.
 Results. In result of the experiments, it was revealed that optimal nutrient media and substrates for obtaining and cultivation of the mycelium are those with addition of the sparging grain and cellulose-containing wastes. For obtaining fruit bodies, we used the substrate composed of the straw with addition of the brewers’ grain. Utilization of nutrient media with similar composition leads to shortening of the period of mycelium adaptation and initiation of its active growth phase when producing the master culture of the fungus. Further, for that reason, increases the speed of colonization by the fungal mycelium the substrate blocks for producing carposomes, and the fungus fruitification occurs more intensively.
 Conclusion. The use of the brewers’ draff for obtaining mycelium and fruit bodies of the edible oyster mushroom creates valuable, ecologically clean and quality nutrition product and facilitates cost effectiveness of its production. Design and application this biotechnology solve the problem of organic waste utilization, which in turn positively stimulates positive changes in the regional ecological situation and contributes partially into the task of import substitution.