Sublethal detergent concentrations increase metabolization of recalcitrant polyphosphonates by the cyanobacterium Spirulina platensis

Abstract

As a consequence of increasing industrial applications, thousand tons of polyphosphonates are introduced every year into the environment. The inherent stability of the C-P bond results in a prolonged half-life. Moreover, low uptake rates limit further their microbial metabolization. To assess whether low detergent concentrations were able to increase polyphosphonate utilization by the cyanobacterium Spirulina platensis, tolerance limits to the exposure to various detergents were determined by measuring the growth rate in the presence of graded levels below the critical micellar concentration. Then, the amount of hexamethylenediamine-N,N,N',N'-tetrakis(methylphosphonic acid) that is metabolized in the absence or in the presence of sublethal detergent concentrations was quantified by (31)P NMR analysis on either P-starved or P-fed cyanobacterial cultures. The strain tolerated the presence of detergents in the order: nonionic> anionic > cationic. When added to the culture medium at the highest concentrations showing no detrimental effects upon cell viability, detergents either improved or decreased polyphosphonate utilization, the anionic sodium dodecyl sulfate being the most beneficial. Metabolization was not lower in P-fed cells--a result that strengthens the possibility of using, in the future, this strain for bioremediation purposes.

Synthesis, theoretical studies, and effect on the photosynthetic electron transport of trifluoromethyl arylamides

“…To substantiate such a hypothesis, the evaluation of the effect of these trifluoromethyl amides against cyanobacterial growth was repeated by supplementing the culture medium with either 160 μmol L −1 SDS or 25 μmol L −1 Triton X100. At these levels, the former detergent had indeed been found to increase the uptake of the polyphosphonate Dequest® 2054 by the cyanobacterium Spirulina platensis without affecting algal growth, whereas the latter had a detrimental effect on polyphosphonate metabolization . In this case, however, the inhibition curves obtained perfectly overlapped those found in the absence of detergents (data not shown).…”

“…At these levels, the former detergent had indeed been found to increase the uptake of the polyphosphonate Dequest ® 2054 by the cyanobacterium Spirulina platensis without affecting algal growth, whereas the latter had a detrimental effect on polyphosphonate metabolization. 13 In this case, however, the inhibition curves obtained perfectly overlapped those found in the absence of detergents (data not shown).…”

“…The concentrations causing 50% inhibition (IC 50 ) and their confidence limits were estimated as detailed above. The effect of detergents on the inhibitory activity of selected brominated amides was evaluated by supplementing the growth medium with either sodium dodecyl sulfate (SDS) or Triton X100 at levels [160 μmol L −1 (0.02× the critical micellar concentration) and 25 μmol L −1 (0.1× the critical micellar concentration), respectively] that had been previously shown to influence polyphosphonate uptake by the cyanobacterium Spirulina platensis strain PCC 9438 without affecting algal growth …”

“…Anhydrous tin(II) chloride and triethylamine were purchased from Vetec (Rio de Janeiro, Brazil) and used as received. 1 H NMR and 13 C NMR spectra were recorded on a Varian Mercury 300 instrument (Varian, Palo Alto, CA, USA) at 300 MHz and 75 MHz, respectively, using CDCl 3 and CD 3 OD as solvents. Infrared spectra were recorded on either a Varian 660-IR, equipped with GladiATR scanning from 4000 to 500 cm −1 or a Perkin Elmer Paragon 1000 FTIR spectrophotometer (Perkin Elmer do Brasil Ltda, São Paulo, Brazil), using potassium bromide (1% v/v) disks, scanning from 600 to 4000 cm −1 .…”

Biodegradation of the aminopolyphosphonate DTPMP by the cyanobacterium Anabaena variabilis proceeds via a C–P lyase‐independent pathway

“…In previous studies the cyanobacterium Spirulina platensis was found able to accomplish partial removal of a model polyphosphonate from wastewaters (Forlani et al ., ), but no information was obtained concerning the steps in the biodegradation process. Here we report the ability of a collection strain of Anabaena variabilis to use DTPMP as a source of phosphorus.…”