Controlled prodution of pullulan by yeast-like organism Aureobasidium pulluans

Bachelor's thesis is focused on study of influence of exogenous stress factors on biomass and pullulan production by microorganism Aureobasidium pullulans. As a part of this work an overview of stress factors, pullulan producers, its structure, function and technological use was introduced. In the experimental part growth characteristics of Aureobasidium pullulans and pullulan production during growth in optimum conditions and under stress were analyzed. The reduced availability of oxygen resulted in a decrease of biomass production accompanied by increased pullulan production. Chemical stress induced by NaCl significantly affected mainly biomass production. The highest production of pullulan was found at 15 g / l of NaCl. Ethanol stress exhibited growth inhibition and at higher concentration also lack of pullulan production. Peroxid stress exhibited no effect on pullulan production. Short-time exposure to low heavy metal concentration (Se(IV), Cr(III)) influenced pullulan production more positively than long-term effect