Phosphorus Uptake by Klebsiella Pneumoniae and Acinetobacter Calcoaceticus

Abstract

The objective of our study was to show that pure cultures of Klebsiella pneumoniae and Acinetobacter calcoaceticus could be Induced to accumulate large amounts of phosphorus (P), when P-starved cultures were enriched with phosphorus either in suspended growth or immobilized cell reactors. Suspended growth cultures of K. pneumoniae were more efficient than those of A. calcoaceticus, with specific uptake rates of 14.1 - 17.1 mg P1−1 hr−1 per O.D. unit, and 5.4 - 10.0 mg P1−1 hr −1 per O.D. unit, respectively. The absolute rate of P accumulation of 24.6 mg P1−1 hr−1 measured for a K. pneumoniae culture was among the highest ever reported in the literature. In an immobilized cell system, which facilitates the separation of the cells (for recycling) from the liquid phase, K. pneumoniae cells entrapped in agar gel beads, remained viable and showed rates of P uptake of 6.1 and 7.9 mg P1−1 hr−1. K. pneumoniae cultures also showed a high capacity for removing dissolved phosphate from municipal wastewater, with greater than 95% P removal in two hours. These studies suggest the important role such high-phosphate accumulating bacteria may play in wastewater treatment systems designed for enhanced biological phosphorus removal.