The Effect Of UV Radiation On Growth Of Yeast And The Preparation Of Live Yeast Cell Derivative

Effects of UV radiation in the culture on physiological properties and metabolism of yeast and the enzymatic conditions of yeast cells injured culture by UV and UV absorption capability of yeast hydrolysate were studied. Then Live Yeast Cell Derivative solution was made.The glucose in the culture by UV radiation was exhausted after 6h. A part of which was transformed into alcohol, but it's contents were lower than the control. The pH was decreased to 3.0 after 12h. So it was necessary to add the glucose to the culture and adjust pH regularly in order to content the yeast normal living .The yeast modality and cytoplasm inclusion were changed by UV radiation. The cell amount was increased from 9.2 108 to 13.8 108 in 72h that was only enhanced 0.5 fold and the bud rate was increased from 3.26% to 7.90% in 60h, then it descended sharply. The results showed that yeast growth was restrained in UV radiation. In UV radiation the yeast could produce self-protective materials and the contents of protein and the nucleic acid in cells reached the greatest value at 72h and the nucleic acid was increased from 8.94% to 9.57%.The effect of VB added into the culture medium on the nucleic acid was better than the yeast extracts. The contents of polysaccharides that were isolated in ways of alkali extraction and acid-alkali extraction by UV radiation were raised by 43.50% and by 29.25%, respectively.The results showed that the optimum enzymatic conditions were the content of suspension yeast 10%, Neutrase 2% (dry weight of the cells), pH6.5, 52 C and the time of hydrolysis 26h. The hydrolysate of yeast after UV injuring culture was prepared by hydrolysis and centrifugation. The OD365 value of the dilution with 10 times was 0.349, which was the 3.46 times of the control. It was worthy biological resist-bask product. Its UV absorbency was more than 95% in 280~400nm and its ability of UV absorption was reduced after the ultrafiltration. So the effects of the enzymatic conditions on the resist-bask produce of Live Yeast Cell Derivative were also importance. The bio-active matter that was extracted from yeast by UV radiation was preliminarily identified glycopeptide.