FIG. 3.

pH-stat-controlled self-hydrolysis of nPHB granules. (A) Eighty-eight milligrams of purified nPHB granules was added (arrow) to 15 ml of 1 mM Tris-HCl, pH 8.5, and incubated at a constant pH at 37°C. (B) Dependence of (initial) hydrolysis rates (nmol NaOH consumed min⁻¹) on the amount of nPHB granules. Conditions were the same as those described above for A. (C) Comparison of hydrolysis rates of nPHB (black symbols) with those of aPHB (white symbols). PHB granules (25 mg/15 ml) were incubated in 1 mM Tris-HCl, pH 8, at 37°C, and the amount of NaOH necessary to keep the pH constant was recorded.