Effect of Different Factors on Biosynthesis of Exopolysaccharide from Antarctic Yeast

ABSTRACT

Psychrophilic yeast Isolate 100, was selected as a producer of exopolysaccharide. A laboratory scheme was created for obtaining of the biopolymer. Biotechnological and physicochemical factors influencing its biosynthesis were investigated. It was determined that inocolum quantity from 6–10%, cultivated for 48 hours at 22° C, is suitable for maximum synthesis. The exopolysaccharide that was synthessed in the culture liquid was thermostable at 50°C to 70°C and it degrades at 80°C. The quantity of the sedimentary polymer, that was synthesis on environment with arabinose and mannose from Isolate 100, after incubation in ethanol at 4°C for 120 hours staying at the time of 120 hours in ethanol at 4 °C, was increased with 40%. The influence of the temperature over drying of the exopolysaccharide at 65°C and 105 °C was studied. At the low temperature of drying the polymer contained near 20% humidity. The effect of the experimental conditions (temperature, time, concentration of 2%, 3%, 4%, 5%) on the apparent viscosity values of the cultural liquid was studied. It was found to reveal a behaviour of non-Newtonian liquid. The power law equation of Oswald- de Waale describing the change of the apparent viscosity was derived.

Keywords:

• Antarctic yeast
• Isolate 100
• exopolysaccharide
• production