Experimental Studies On Biological Effect Of Saccharomyces Cerevisiae Under Low Intensity Ultraound

The application of ultrasound to biotechnology is a hotspot, especially to Genetic engineering in recent years. It has been found that low intensity ultrasound can improve the penetration of cell membrane, increase the activity of enzyme, modify the metabolism of cells and promote their growth and so on, which indicates that ultrasound have a promising application in the enzyme engineering and fermentation engineering. We studied mainly the influence of low intensity ultrasound on Saccharomyces cerevisiae's growth and physiology, and primarily discussed its mechanism of growth in this paper.Research and result 1.The experiment used CY-5D ultrasonic equipment which can produce low intensity ultrasound to advance the growth of biomass, and tested the influence of ultrasound on each growth phase of Saccharomyces cerevisiae with orthogonal experiment. It was found (1) low intensity ultrasound can accelerate the growth of Saccharomyces cerevisiae at the lag phase and logarithmic phase under proper conditions, and improve the growth rate of cells; But for the Saccharomyces cerevisiae at the stationary phase, low intensity ultrasound had no effects; At the lag phase, the optimum parameters are that frequency is 30KHz, power 6W, interval 30 seconds, work time 1 second and whole time 15 mins. At the logarithmic phase, the parameters changed into 24KHz, 2W, 15 seconds, 1 second and 30 mins, respectively; (2) the influence of low intensity ultrasound on the temperature of culture medium was negligible while the ultrasound make the pH of culture medium rise relatively and the culture medium form foam at the logarithmic phase. 2.At the logarithmic, Saccharomyces cerevisiae were subcultured after stimulated by low intensity ultrasound and repeat that more than three times, the damage, fermentability and physiological characteristics of cells were tested under ultrasound and subculture. It was showed that (1)proper low intensity ultrasound made no injury to cells;(2)the fermentability temporarily increased under the low intensity ultrasound, but the fermentability of filial generation had no change. (3) the agglutination of filial generation decreased, but there was no influence on the production of ascospore; (4)low intensity ultrasound increased the activity of proteinase in the culture medium. 3.The effects of low intensity ultrasound on the activity of the protective enzymeSOD and the fermentative enzyme ADH of stimulated Saccharomyces cerevisiae were studied at the logarithmic phase, and that of filial generation was also explored. The results were (1) low intensity ultrasound can increase the activity of SOD and ADH;(2) after stimulation and subculture , the activity of SOD was higher than that of the contrast, but .the activity of ADH was no change. 4.To explore the mechanism of low intensity ultrasound enhancing the proliferation of Saccharomyces cerevisiae primarily, this paper studied the contribution of Ca2+ to the proliferation and tested the influence of low intensity ultrasound on the content of Ca2+ in cells with plasma emission spectrograph. The results showed that Ca2+ can enhance the proliferation of Saccharomyces cerevisiae and the low intensity ultrasound can increase the content of Ca2+.