| 摘要 |
PURPOSE:To produce a calcium ion solubilization agent by improving the calcium ion solubilization activity of gamma-polyglutamic acid (PGA) produced by a microorganism. CONSTITUTION:PGA produced by a microorganism, e.g. a PGA-producing Bacillus (e.g. Bacillus subtilis) is treated with an acid or an alkali, preferably hydrochloric acid, caustic soda, caustic potassium or calcium hydroxide all of which can readity be neutralized after the treatment under a condition wherein the conversion of the ninhydrin color reaction reaches 0.4 to 6%, preferably 2 to 3% by suitably combining PGA concentration within a range of 0.5 to 2wt.%, preferably 0.8 to 1.2wt.%, final concentration of the added acid or alkali within a range of 0.01 to 1N, preferably 0.08 to 0.2N, treatment temperature within a range of 80 to 100 deg.C, preferably 85 to 95 deg.C and treatment time within a range of 30min to 5hr, preferably 50min to 2hr. |
