Abstract
The study was aimed on the determination of biodegradation rate of extruded starch carriers, with or without immobilized microorganisms in diversified storage conditions. The research was conducted on potato starch, in which Saccharomyces cerevisiae yeast cells were immobilized. Preparations with and without yeasts were than placed for 84 days in the environments of: light soil, heavy soil, compost, water and activated sludge. After 0, 7, 14, 21, 49 and 84 days of storage the preparations were perfused with water and analyzed. In the recovered samples the following tests were carried out: the force causing fracture, the elongation caused by the mentioned force, the mass and the diameter of the carrier. Due to the degradation the size and the mechanical properties of the samples were decreased. The rate of the degradation was strongly dependent on the environment of the storage. The fastest degradation of the carriers were observed for compost and heavy soil, while the slowest biodegradation was observed for the samples placed in the water environment. The rate of biodegradation was also influenced by the Saccharomyces cerevisiae yeasts. The rate of biodegradation was faster in the samples containing yeast cells, than in the extrudates without the microorganisms.