Neutralization of acidic drainage by <i>Cryptococcus</i> sp. T1 immobilized in alginate beads

<p>We isolated <i>Cryptococcus</i> sp. T1 from Lake Tazawa’s acidic water in Japan. <i>Cryptococcus</i> sp. T1 neutralized an acidic casamino acid solution (pH 3.0) and released ammonia from the casamino acids to aid the neutralization. The neutralization volume was estimated to be approximately 0.4 mL/h. The casamino acids’ amino acids decreased (1.24→0.15 mM); ammonia increased (0.22→0.99 mM). We neutralized acidic drainage water (1 L) from a Tamagawa River neutralization plant, which was run through the column with the T1-immobilized alginate beads at a flow rate of 0.5 mL/min, and observed that the viscosity, particle size and amounts of the alginate beads affected the acidic drainage neutralization with an increase of the pH value from 5.26 to 6.61 in the last fraction. An increase in the Al concentration decreased <i>Cryptococcus</i> sp. T1’s neutralization ability. After 48 h, the pH of acidic water with 50 mg/L Al was apparently lower than that without Al. Almost no pH increase was observed at 75 mg/L.</p> <p>A bioreactor with <i>Cryptococcus</i> sp. T1-immobilized in alginate beads neutralized an acidic casamino acid solution and acidic drainage.</p>