| Waste beer yeast is a by-product of beer industry, produced after primary fermentation and fermentation brewing process in the process of beer production. Beer yeast is very nutritious, contains 48% protein, which includes 8 kinds of essential ammonia acid needed for human body; the yeast polysaccharide content is 25%~25%, which have lots of medical value, such as strengthening immune system reducing blood-lipid and blood sugar, etc. Phospholipid is one kind of natural amphiphilic substances, which is not only being increasingly used as surfactants and emulsifiers in industry but also a kind of food additives. The comprehensive utilization of waste beer yeast not only creates a good economic, but also reduces environmental pollution and extends the industrial chain. This study mainly introduced the research of extraction methods of phospholipids,β-(1,3)-D-glucan, mannan and protein peptide from waste beer yeast. Main results for this study are as follows:This study used mixed organic solvent after the hydrolysis of the yeast cell wall to study the combination of n-heptane, n-hexane, isopropyl alcohol and ethanol on the influence of yeast phospholipids extraction yield. The optimum condition as follows: The extraction solvent is HPIP, solid ratio is 1:11, 85℃ treatment 30 min, repeat 3 times. The rate of recovery is 3.87%, which reached to 80.29% of the traditional method. The extraction of phospholipids with HPIP has been testified by the experiments.In this paper, the yeast phospholipids were purified and identified with solid phase extraction and TLC technique. The optimal extractive conditions are developed: 400 mg/mL of phospholipid sample on volume is 0.5 mL, 5 mL n-hexane elution ergosterol, 4 m L chloroform elution neutral fat, 10 m L methanol elution phospholipid; the recoveries of phospholipids were about 80.96%. Each pillar of solid phase extraction can repeat twice. It was better to separate phospholipids by using chloroform-methanol-water(6.07:2.43:1.5) as the mobile phase. TLC spray reagents of phospholipids indicated that there are four same color reference substances in the corresponding location on chromatography, which are Phosphatidyl Choline(PC) and Phosphatidyl Ethanolamine(PE), Phosphatidyl Inositol(PI), Phosphatidylserine(PS) respectively. This technology is simple and auto-operation is easy, and the level of organic solvent is lower.In this paper, different extracted techniques of protein and polysaccharide from waste yeast were studied, and decided to extract β-(1,3)-D-glucan and mannan with enzyme decomposition method, and subside the protein peptide in the polysaccharide solution with sevage. The best condition is obtained as follows: the concentration of NaOH is 2.03%,64.20 ℃ treatment1.04 h. The recovery rate ofβ-(1,3)-D-glucan was 14.87%, it increased by 4% compared to the predicted value. The recovery rate of mannan was 19.64%, it reduced by 1.2% compared to the predicted value. The recovery rate of protein peptide was 16.56%, it increased by 2.4% compared to the predicted value.The results showed that the molecular weight of the protein peptide for less than 3000 accounted for 81.5%,and less than 1000 for 60.31%.This shows that the product obtained are in the form of short peptides or amino acids.The molecular weight of mannan is about 213 KD.β-(1,3)-D-glucanwere degraded in the deinking effluent.The molecular weight greater than 200 KD accounted for 66.07%,which shows that the ratio of strong biological activity is higher.This study mainly introduced the research of synchronous extraction methods of phospholipids,β-(1,3)-D-glucan, manan and protein peptide from waste beer yeast. It provides the theoretical basis for developing product with high added value by using beer yeast in beer industry. |
PDF Full Text Request