NON-TRADITIONAL RAW MATERIALS FOR BIOTECHNOLOGICAL PRODUCTIONS AND SOME ENVIRONMENTAL ASPECTS OF THEIR DISPOSAL

Abstract

It has been proved in the work that non-traditional, annually renewable wastes of plant raw materials − cuttings of fruit trees, hop stems and castor bean stems − are rational to be used for further biotechnological processing in order to obtain a valuable protein feed supplement. The negative impact of burning these plant wastes on soil microbiota has been confirmed. Technological properties, chemical and biopolymer composition of the plant waste have been studied. It has been found out that the optimum particle sizes for all three types of the studied waste are 20–35 mm in fibre length. Such grinding degree provides the best diffusion of the hydrolyzing agent into the particles of the raw material and the extraction of monosaccharides into the solution. All types of the analysed plant waste have a high content of polysaccharides, extractive substances, which will allow to use them as potential raw materials for the development of nutrient media to cultivate microorganisms in biotechnological industries. Acid degradation of biopolymers of the analysed raw materials has been carried out in laboratory conditions. Hydrolysate-based nutrient media have been obtained in laboratory conditions and their biological quality has been studied. Yeast culture strains, which are able to grow actively on the hydrolysates of fruit tree cuttings, hop and castor bean stems, have been selected, and Candida tropicalis culture has been cultivated during the process of periodic cultivation. The negative impact of burning plant residues on the soil microbiological status has been investigated. Samples of the soil were taken from the experimental plot before and after burning of the plant waste, microbiological studies of the total number of mesophilic aerobic and facultative anaerobic microorganisms, and nitrogen-fixing ones were conducted, since they are the only living organisms capable of absorbing molecular nitrogen from the air and incorporating it into the cycle of nitrogenous substances. The total number of microbes is reduced by 45%, and the number of nitrogen-fixing bacteria is halved. The process of their regeneration is rather slow, which will significantly affect soil fertility, and soil ashing can lead to changes in crops capable of producing high yields on this soil, and will require scientifically based crop rotations.