Extraction Method Of Yeast Glucan

There are many studies on the extraction process of yeast glucan both domestically and internationally, mainly including acid extraction, alkali extraction, acid-base comprehensive method, and organic solvent extraction method.
Acid extraction method
A study was conducted on whether acetic acid, formic acid, and phosphoric acid are suitable for acid hydrolysis to extract yeast glucan. The results showed that the main structure and branched structure of yeast glucan extracted after acid hydrolysis were basically unchanged. Acetic acid was used to extract β - glucan from brewing yeast. The study found that the optimal process conditions for acid extraction of glucan were: HAc concentration of 6%, extraction temperature of 90 ℃, extraction time of 6h, and solid-liquid ratio of 1:6. Under the optimal extraction process, the yield of yeast glucan was 21.58%, the protein content was 7.21%, and the polysaccharide content was 71.46%. Paper chromatography experiments showed that the hydrolysis product contained both mannose and glucose.
From the above, it can be seen that although acid extraction has a high yield, it contains a large amount of mannose and protein, and can also lead to the degradation of polysaccharides.
Alkali extraction
Suspend the cell wall in a 3% (W/V) NaOH solution and leave it at 4 ℃ for 9 days. The suspended portion on the surface is intermittently removed, and the remaining portion is centrifuged for 15 minutes to obtain cell wall residue. By adding aminoacetic acid to adjust the pH of the extracted solution to 10, the solution becomes colloidal. Centrifuge for 30 minutes and rinse thoroughly with a large amount of water. Then dissolve it in a 3% (W/V) NaOH solution, and when the pH of the solution is adjusted to 10, the pectin fragments precipitate again. Paper chromatography showed that the main product of precipitation hydrolyzed with 2mol/L H2S04 was glucose.
Domestic and foreign studies have shown that alkaline extraction has high purity and low protein residue, but the yield of polysaccharides is low. Moreover, a large amount of alkaline treatment can pollute the environment and lead to polysaccharide degradation.
Acid base comprehensive extraction method
Disperse yeast into NaOH solution and stir, then add water and collect the precipitate by centrifugation. Disperse the precipitate into NaOH solution and collect it by centrifugation. Wash the precipitate with water three times, extract with HCl, collect the precipitate by centrifugation, and dry to obtain yeast β - (1,3) - D-glucan product.
The product extracted by the acid-base method has high purity, low protein content, and high yield. However, this method is complex, cumbersome to operate, time-consuming, and uses multiple organic solvents for dehydration, resulting in a large amount of waste liquid and environmental pollution.
other
The traditional method of preparing yeast glucan through acid-base treatment requires a large amount of acid and alkali, the process is cumbersome, and the labor intensity is high. The use of acid and alkali in extraction can easily lead to the degradation of polysaccharides and affect the physiological activity of pectin.