Degradation of pentaerythritol tetranitrate by Enterobacter cloacae PB2

Abstract

A mixed microbial culture capable of metabolizing the explosive pentaerythritol tetranitrate (PETN) was obtained from soil enrichments under aerobic and nitrogen-limiting conditions. A strain of Enterobacter cloacae, designated PB2, was isolated from this culture and was found to use PETN as a sole source of nitrogen for growth. Growth yields suggested that 2 to 3 mol of nitrogen was utilized per mol of PETN. The metabolites pentaerythritol dinitrate, 3-hydroxy-2,2-bis-[(nitrooxy)methyl]propanal, and 2,2-bis-[(nitrooxy)methyl]-propanedial were identified by mass spectrometry and 1 H-nuclear magnetic resonance. An NADPH-dependent PETN reductase was isolated from cell extracts and shown to liberate nitrite from PETN, producing pentaerythritol tri-and dinitrates which were identified by mass spectrometry. PETN reductase was purified to apparent homogeneity by ion-exchange and affinity chromatography. The purified enzyme was found to be a monomeric flavoprotein with a M r of approximately 40,000, binding flavin mononucleotide noncovalently. MATERIALS AND METHODS Chemicals. PETN, GTN, and EGDN were kindly provided by the Defence Research Agency (Fort Halstead, United Kingdom). Other chemicals were of analytical grade and were obtained from BDH Ltd. (Poole, United Kingdom), Sigma Chemical Company Ltd. (Poole, United Kingdom), or Aldrich (Gillingham, United Kingdom). Liquid chromatography. High-performance liquid chromatography (HPLC) measurements were performed with a Hewlett-Packard 1050 series component system consisting of a multiple wavelength detector, quaternary pump, and 21-vial autosampler. Integrations were performed by using Hewlett-Packard Chemstation software. Samples (15 l) were separated with a 10-m C 18 reversed-phase column (length, 25 cm; diameter, 4.6 mm; HPLC Technology Ltd., Macclesfield, United Kingdom). A reverse-phase isocratic mobile phase consisting of methanol-water (65:35, vol/vol) was delivered at a flow rate of 1.5 ml/min. PETN elution was monitored at 205 nm.

Enterobacter asburiae KE17 association regulates physiological changes and mitigates the toxic effects of heavy metals in soybean

“…Dadook et al (2014) observed that optimal growth of various strains of Azotobacter chroococcum occurred at 6 ppm to 20 ppm ZnSO 4 , and suggested that higher concentrations of Zn in agricultural soil are harmful to beneficial microorganisms and reduce soil fertility. Several species of Enterobacter have been identified, and their ability to degrade phosphonate, glyphosate, pentaerythritol tetranitrate, trinitrotoluene, organophosphates, lignin and synthetic dyes has been reported (Lee et al 1992;Dick & Quinn 1995;Binks et al 1996;French et al 1998;Singh et al 2004;Manter et al 2011;Mukherjee & Das 2014). The efficiency of using Enterobacter spp.…”

Organophosphonate metabolism by a moderately halophilic bacterial isolate

“…1). No growth of isolate VH1 was observed above that of a negative control lacking amino acids when it was screened for its ability to utilise a range of aminophosphonates (2AEP, 3-aminopro- Results were scored negative if the protein yield, as measured by the method of Binks et al [12], was less than 20% of that of the positive control containing 1 mM inorganic phosphate. Results are means of duplicates which on no occasion varied by more than 5%.…”

“…Phosphate release during growth was assayed for by the method of Fiske and SubbaRow [11]. Maximal growth was expressed as the yield of protein ml 31 from cultures as determined by the method of Binks et al [12].…”

The utilization of 4-aminobutylphosphonate as sole nitrogen source by a strain of Kluyveromyces fragilis

“…Inorganic phosphate was determined by the colorimetric method of Fiske and SubbaRow [11]. The protein yield from K. fragilis cultures was assayed by the method of Binks et al [12] ; protein concentration in cell extracts was measured by the method of Bradford [13].…”