Stimulation of phosphate uptake and polyphosphate accumulation by activated sludge microorganisms in response to sulfite addition

摘要

Enhanced phosphate removal from wastewaters is dependent on the synthesis and intracellularnaccumulation of polyphosphate by sludge microorganisms. However the role played bynpolyphosphate in microbial metabolism and the factors that trigger its formation remainnpoorly-understood. Many examples of the accumulation of the biopolymer by environmentalnmicroorganisms are documented; these include a recent report of the presence of largenpolyphosphate inclusions in sulfur-oxidizing marine bacteria. To investigate whether any link mightnexist outside the marine environment between the presence of reduced sulfur compounds andnenhanced levels of microbial phosphate uptake and polyphosphate accumulation, activated sludgencultures were grown under laboratory conditions in media that contained sulfite, thiosulfate,nhydrosulfite or tetrathionate. Only in the presence of sulfite was there any evidence of anstimulatory effect; in medium that contained 0.5 mM sodium sulfite some 17% more phosphatenwas removed by the sludge, whilst there was an almost two-fold increase in intracellularnpolyphosphate levels. No indications of sulfite toxicity were observed.