Growth of Pseudomonas aeruginosa in tap water in relation to utilization of substrates at concentrations of a few micrograms per liter

Abstract

Five Pseudomonas aeruginosa strains were tested for the utilization of 47 low-molecular-weight compounds as their sole sources of carbon and energy for growth at a concentration of 2.5 g/liter. Of these compounds, 31 to 35 were consumed. Growth experiments in tap water at 15 degrees C were carried out with one particular strain (P1525) isolated from drinking water. This strain was tested for the utilization of 30 compounds supplied at a concentration of 25 microgram of C per liter. The growth rate (number of generations per hour) of strain P1525 in this tap water was approximately 0.005 h-1, and with 10 compounds it was larger than 0.03 h-1. An average yield of 6.2 x 10(9) colony-forming units per mg of C was obtained from the maximum colony counts (colony-forming units per milliliter). The average yield and maximum colony count of strain P1525 grown in tap water supplied with a mixture of 45 compounds, each at a concentration of 1 microgram of C per liter, enabled us to calculate that 28 compounds were utilized. Growth rates of two P. aeruginosa strains (including P1525) in various types of water at 15 degrees C were half of those of a fluorescent pseudomonad. The concentrations of assimilable organic carbon calculated from maximum colony counts and average yield values amounted to 0.1 to 0.7% of the total organic carbon concentrations in five types of tap water. The assimilable organic carbon percentages were about 10 times larger in river water and in water after ozonation.

Survival of allochthonous bacteria in still mineral water bottled in polyvinyl chloride (PVC) and glass

“…cloacae had very low mortality rate and would have persisted in the mineral water for a long period of time irrespective of the test conditions. Pseudomonas aeruginosa is frequently isolated from water and several studies show it to grow even under conditions of very limited nutrient content (van der Kooij et al 1982).…”

Global physiological analysis of carbon‐ and energy‐limited growing Escherichia coli confirms a high degree of catabolic flexibility and preparedness for mixed substrate utilization

“…a Spirillum sp. grew in unsupplemented sterile seawater (Jannasch, 1969) and Pseudomonas fluorescens P‐17 multiplied in sterile‐filtered drinking water (van der Kooij et al ., 1982). Furthermore, the standard method for determining the concentration of microbially assimilable organic carbon (AOC) is based on cellular growth yield of a reference strain, and shows that in drinking water bacteria can grow with as little as 1 µg l −1 acetate‐carbon equivalents (van der Kooij, 2002).…”

Biological stability of groundwater

“…The authors attribute this finding to the fact that the HGR is based on the maximum growth of many types of heterotrophic bacteria, whereas AOC determination is based on the maximum growth of P17 and NOX, which are surrogates for the presence of amino acids, carboxylic acids, carbohydrates, and polyalcohols and aromatic acids. 5,16 Moreover, these findings suggest that HPC is a good representation of those bacteria that are able to utilize the available carbon in water samples.…”

“…The most likely explanation for the increase in AOC of the effluent samples is that carbon fines from the GAC columns were present in the water samples. 15,16 Presumably, carbon fines laden with adsorbed carbon provided a nutrient source for P17 and NOX. The fact that the HGRs of the GAC columns were higher than those of the sand-anthracite columns also supports this hypothesis.…”