Glucan preparations
Particulate β-glucan is solubilized at elevated pressure and temperature to form soluble β-glucan. The method is safe and economical and produces a product that is an improved pharmaceutical agent.
1. A process for producing underivatized, soluble β-glucan derived from Saccharomyces cerevisiae and having immunostimulating properties and an average molecular weight between about 120,000 Da and about 205,000 Da; soluble β-glucan having a molecular weight over 380,000 Da in an amount less than or equal to 10%; and β-glucan having a molecular weight under 25,000 Da in an amount less than or equal to 17%, the process comprising:
applying pressure to a suspension comprising particulate β-glucan and acetic acid; and heating the suspension for a time sufficient to form the soluble β-glucan, wherein the suspension is buffered to a pH of about 3.6, and wherein the underivatized, soluble β-glucan is not treated with caustic solution during the process.
2. The process of claim 1 and further comprising:
clarifying the soluble β-glucan.
3. The process of claim 2 wherein the soluble β-glucan is clarified by centrifugation, filtration or a combination thereof.
4. The process of claim 1 wherein the suspension is in a vessel in which substantially all oxygen is removed.
5. The process of claim 4 wherein the oxygen is removed by purging the vessel with nitrogen.
6. The process of claim 1 and further comprising: separating the soluble β-glucan into fractions based on molecular weight.
7. The process of claim 6 wherein the soluble β-glucan is separated by chromatography.
8. A composition comprising:
underivatized, soluble β-glucan derived from Saccharomyces cerevisiae and having immunostimulatory properties and an average molecular weight between about 120,000 Da and about 205,000 Da;
soluble β-glucan having a molecular weight over 380,000 Da in an amount less than or equal to 10%; and β-glucan having a molecular weight under 25,000 Da in an amount less than or equal to 17%,
wherein the underivatized, soluble β-glucan is prepared by applying pressure to a suspension comprising particulate β-glucan and acetic acid, and heating the suspension for a time sufficient to form the soluble β-glucan, wherein the suspension is buffered to a pH of about 3.6, and wherein the underivatized, soluble β-glucan is not treated with caustic solution during preparation.
9. The composition of claim 8 where the underivatized, soluble β-glucan forms a triple helix aggregate having a molecular weight between about 25,000 Da and about 380,000 Da.
10. The composition of claim 8 where the underivatized, soluble β-glucan is prepared by applying about 35 PSI of pressure to the suspension.
11. The composition of claim 8 where the underivatized, soluble β-glucan is prepared by heating the suspension to about 135° C.
12. The composition of claim 8 where the underivatized, soluble β-glucan has a molecular weight over 380,000 Da in an amount of from 4% to 8%.
13. The composition of claim 8 where the underivatized, soluble β-glucan has a molecular weight under 25,000 Da in an amount of from 8% to 13%.
14. The composition of claim 8 where the underivatized, soluble β-glucan has a reducing sugar of from 1.0% to 1.1% of total hexose.
15. The composition of claim 8 where the suspension is heated in the presence of about 0.61 g of sodium acetate and about 5.24 ml glacial acetic acid per liter of the suspension.
16. The composition of claim 8 where the underivatized, soluble β-glucan is prepared in the presence of nitrogen.
17. The composition of claim 8 where the preparation of the underivatized, soluble β-glucan does not use formic acid or sulfuric acid.
18. The composition of claim 8 where the soluble β-glucan is purified by chromatography.
19. The composition of claim 8 where the soluble β-glucan is purified by hydrophobic interaction chromatography.