Studies on the memthods of recovering valuable components from brewer;s spent yeast

• Main Author: 陳螢龍
• Other Authors: 段國仁
• Format: Others
• Language: en_US
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/94173862687857501222

碩士 === 大同大學 === 生物工程研究所 === 90 === Abstract The aim of this project was try to extract valuable components from spent yeast of Chien Kuo Brewery, Taipei. The experiments include studies of disintegration methods of yeast, optimum reaction conditions of enzymatic conversion of protein to amino acids, separation of RNA from trapped materials of ruptured yeast. It was found that yeast disintegration by high pressure homogenizer is the most efficient methods comparing to ball mill (DYNO-Mill), homogenizer (APV). The protein released from yeast cell is 51.3 %, 47.3 %, 37.5 %, 41.1 % for the yeast ruptured by high pressure homogenizer, ball mill, homogenizer and autolysis respectively. The ruptured cell was adjusted to pH 8 by ammonia to precipitate the cell wall debris and RNA, leaving other trapped materials, mostly protein, in the solution. The RNA was dissolved in hot water ( 80 °C) containing 10 % (w/w) NaCl at pH 8 adjusted by ammonia. The cell wall debris was separated from RNA by centrifugation. The supernatant was adjusted to pH 3 by HCl to precipitate the RNA. The total amount of RNA recovered from the processes described above was 6.54 % on a dry cell weight basis. Protein in the trapped solution was hydrolyzed by 0.2 % (v/v) proteases (Alcalase, Flavourzyme, NOVO). Amino acids in the trapped solution increased from 32 mg/100mLto 77.16 mg/100mL The optimum pH for amino acid conversion is 7.