Extraction Of RNA From The Waste Brewers Yeast

Waste brewers yeast is one of the main by-products in beer production. The yeast is abundant in Proteins, ribonucleic acids, vitamins and other valuable components. It is extremely importment to exploitate resource-orientedly the waste brewers yeast. This paper concentrated on the technique of extracting RNA from the waste yeast. The method of extracting RNA using alkalescent salt was established. The results are as follows:1. Studies on the pretreatment of waste bewers yeast. Conditions of the pretreatment on the waste brewers yeast were optimized: the waste beer yeast was washed twice with 2 times volume of deionized water, sieved with a 120-head screen, and then washed with 2 times the volume of 0.5% sodium bicarbonate solution, finally, washed twice with 2 times the volume of deionized water.2. After compared different methods of extracting RNA, the technics of extracting RNA using alkalescent salt was established. With single factor design and orthogonal design analysis, the effect of NaCl concentration, pH value, extraction time and temperature, and yeast contentration on RNA extraction was inensively studied. Then the method of extracting RNA using alkalescent salt was estabilished and the optimum extraction process parameters were obtained. The extraction temperature was 85℃, the extraction pH was 7.5, the concentration of NaCl was 6.5 %( W/W), the extraction time was 3h. Under the optimal conditions, the RNA extraction rate from waste brewers yeast (by dry weight) was 5.76%, and the purity of the extracted product was up to 90.3%.3. The method of eliminating proteins from RNA was studied. After Compared with the isoelectric point of precipitation and ammonium sulfate precipitation protein method, the method of eliminating proteins using the protease was selected. The appropriate amount of protease was 40 U/g, protein removal rate reached 70.1%, the purity of RNA samples was up to 92.3%. After ultraviolet and infrared scanning pattern analysis, the sample was identified as RNA.4. A reasonable scheme of the comprehensive utilization was proposed after studing the treatment of the waste water produced during the RNA extraction process, the waste beer yeast removed RNA, and the by-products. The alcohol and NaCl in waste water could be recoved for salvage, and the waste beer yeast removed RNA could be used as resources for extracting proteins or as feed protein additives, mixed feed and so on.The thesis was of practically importance for energy-saving and emissions reduction, further exploitation on the waste, and economic benefits. The foundation was laid for the resource-oriented exploitation on the waste brewers yeast.