Enzymic Hydrolysis Of Cell Wall And Pigment Extraction On Phaffia Rhodozyma

Astaxanthin(3,3'-dhydroxy-β,β'–carotene-4, 4',-dione ) is a kind of Carotenoid. Due to its characteristic pigmenting property and especial biological functions of preventing diseases like cancer, cardiovascular diseases, immune-system decline, and scavenging free radicals, it has generated considerable interest for food, feed, cosmetic and pharmaceutical. Phaffia rhodozyma, a kind of red yeast is considered as a potential candidate to scale up industrial production of natural astaxamhin. This paper studied the technology of cell wall breaking of Phaffia rhodozyma produing astaxanthin and the extraction and characteristics of pigments.In the base of optimized culture before, enzymatic treatment using complex enzyme composed of protease and mannanase had obvious effect on breaking down the cell wall of phaffia rhodozyma. Complex enzyme with the dose of 100mg/L yeast liquid was added into the yeast liquid after the yeast had been cultivated for 72h. The results showed that enzymatic hydrolyzing for 72h under 38℃could make the breakage rate of the yeast cell wall reach about 90%. However, adding permeating agents into the yeast liquid during enzymatic hydrolysis had no effect on improving the breakage rate of the yeast.After fed-batch fermentation using 10L fermentor and enzymatic treatment of breaking the cell wall of yeast, it was proved that 128h pH-stat gloucose feeding culture, 100mg enzyme in 1L yeast liquid, and enzymatic treatment 72h under 38℃obtained a breakage rate at nearly 90% and the yield of carotenoids turned to be 50ug/mL yeast liquid.Compared with several solvents, acetone was selected as the best for extraction. The optimal conditions for extraction were as list: the ratio of material and solvent was 1:10, triple extracted at 45℃for 60 min.The stability and capacity of scavenging free radicals of the pigments obtained from different treatment as alkali, acid-heat and enzymatic methods for breaking the cell wall were studied. And it was found that the capacity of scavenging free radicals obtained from enzymatic treatment was the strongest. While the stability to heat and lightness was between the other two. It was confirmed that of the three methods the influence to the activity of Astaxanthin via enzymatic treatment was much smaller.