New Strategies for the Isolation of Microorganisms Responsible for Phosphate Accumulation

Abstract

Several strategies were used to isolate organisms involved in the uptake and subsequent release of inorganic phosphate from waste water sludge. These included direct staining for polyphosphates (polyP), growing in 32P inorganic phosphate followed by autoradiography, resistance to dicyclohexyl carbodiimide (DCCD), an ATPase inhibitor, and isolation on the basis of the buoyant density of the cell. Among those microorganisms isolated, three were identified as Acinetobacter lwoffii, A. calcoaceticus and Pseudomqnas vesicularis. The Ps. vesicularis culture had 31% of phosphate as polyP. 31P NMR analysis of the whole cells revealed the presence of polyP when the cultures were grown aerobic-ally to the late stationary phase and its subsequent loss during anaerobic incubation. Loss of polyP was also associated with a decrease in buoyant density of the cell. In the presence of DCCD, there was a decrease in the polyP peak, but a substantial increase in the sugar phosphates which is consistent with a hypothesis that polyP is used as a reserve energy source, Ps. vesicularis cells showed a two-fold increase in the level of polyphosphatase during early stationary phase, but a thirty fold increase in polyphosphate kinase activity during late stationary phase. This increased enzyme activity is consistent with the increased polyP synthesis during late stationary phase.

Micropruina glycogenica gen. nov., sp. nov., a new Gram-positive glycogen-accumulating bacterium isolated from activated sludge.

“…In the past few decades, the microbiological aspect of EBPR or activated sludge processes has been extensively studied to improve the process operation (Bond et al, 1995 ;Cloete et al, 1985 ;Cloete & Steyn, 1987 ;Nakamura et al, 1991 ;Streichen et al, 1990 ;Suresh et al, 1985 ;Wagner et al, 1993Wagner et al, , 1994Yoshimi et al, 1996). One approach to understanding the biochemical mechanism was the isolation of representative bacteria enriched in the process.…”

“…Other known bacterial isolates include Pseudomonas sp. (Suresh et al, 1985), Arthrobacter globiformis (Shoda et al, 1980) and Lampropedia spp. (Stante et al, 1997).…”

Ecological Aspects of Biological Phosphorus Removal in Activated Sludge Systems

“…A large number of other bacteria is also able to store Pi as poly-P granules (Meganck and Faup, 1988). Based on their high numbers in sludges showing enhanced phosphorus removal, the following species have been suggested to be also involved in the process: Aeromonas (Brodisch and Joyner, 1983), Pseudomonas (Brodisch and Joyner, 1983;Suresh et al, 1985), Klebsiella (Mostert et aI., 1989), Arthrobacter (Shoda et al, 1980), gram-positive bacteria (Nakamura et aI., 1989;Brodisch and Joyner, 1983), Microthrix (Meganck, 1987), Moraxella (Meganck, 1987;Streichan and SchOn, 1991), and Xanthobacter (Streichan et al, 1990).…”

Polyphosphate-dependent enzymes in some coryneform bacteria isolated from sewage sludge

“…Although the enzymes polyphosphate : AMP phosphotransferase and adenylate kinase have been shown to form ATP from native and synthetic polyphosphate in strain Acinetobacterjohnsonii 210A [5,22] and several other strains belonging to the genus Acinetobacter [12], the role of this energy generating process within the overall process of 'biological' phosphate removal is far from clear. Several reports described the predominance of other genera than Acinetobacter in activated sludges showing enhanced phosphate removal [3,13,19,21].…”