Isolation of a Pseudomonas sp. Which Utilizes the Phosphonate Herbicide Glyphosate

Abstract

A strain of bacteria has been isolated which rapidly and efficiently utilizes the herbicide glyphosate ( N -phosphonomethylglycine) as its sole phosphorus source in a synthetic medium. The strain (PG2982) was isolated by subculturing Pseudomonas aeruginosa ATCC 9027 in a synthetic broth medium containing glyphosate as the sole phosphorus source. Strain PG2982 differs from the culture of P. aeruginosa in that it is nonflagellated, does not produce pyocyanin, and has an absolute requirement for thiamine. Strain PG2982 has been tentatively identified as a Pseudomonas sp. strain by its biochemical activities and moles percent guanine plus cytosine. Measurements of glyphosate with an amino acid analyzer show that glyphosate rapidly disappears from the medium during exponential growth of strain PG2982. In batch culture at 30�C, this isolate completely utilized 1.0 mM glyphosate in 96 h and yielded a cell density equal to that obtained with 1.0 mM phosphate as the phosphorus source. However, a longer lag phase and greater generation time were noted in the glyphosate-containing medium. Strain PG2982 can efficiently utilize glyphosate as an alternate phosphorus source.

Microbial degradation of organophosphorus compounds

“…There has been no report of the utilization of glyphosate as a source of carbon or nitrogen (Dick & Quinn, 1995). Several species of Pseudomonas have been isolated which can degrade glyphosate (Moore et al, 1983;Tolbot et al, 1984;Jacob et al, 1988;Quinn et al, 1989). Similarly, a Flavobacterium sp.…”

“…GLP-1 and Pseudomonas sp. PG2982 degrade glyphosate by initial cleavage of the C-P bond, resulting in the production of sarcosine (N-methylglycine) by C-P lyase activity (Moore et al, 1983;Shinabarger & Braymer, 1984;Pipke et al, 1987;Liu et al, 1991;Dick & Quinn, 1995). Rhizobium meliloti has also been reported to degrade glyphosate by this pathway but, unlike other bacteria, it has only one C-P lyase, which is able to degrade a wide range of phosphonates (Park & Hausinger, 1995).…”

Microbial metabolism of sulfurand phosphorus-containing xenobiotics

“…Glyphosate is rapidly degraded in the environment, and a number of bacterial species have been isolated which can break down the compound. These include a Flavobacterium species [21], several Pseudomonas species [22][23][24][25] (of which the best studied is Pseudomonas sp. PG2982 [23]), an Alcaligenes isolate [24], Bacillus megaterium strain 2BLW [22], Arthrobacter sp.…”

“…These include a Flavobacterium species [21], several Pseudomonas species [22][23][24][25] (of which the best studied is Pseudomonas sp. PG2982 [23]), an Alcaligenes isolate [24], Bacillus megaterium strain 2BLW [22], Arthrobacter sp. GLP-1 [26], four different Rhizobium species [27] and three Agrobacterium species [27,28] (1) are catalysed in vivo by a 'C-P-lyase'.…”

“…The enzyme or enzymes responsible tk)r the key dephosphonylation step are known by the general name 'C-P lyase'. Despite extensive efforts to stabilize them [23,26,28,31,32], C-P lyase activity measured as alkane release from alkanephosphonates has never been observed in cellfree extracts. It has generally been assumed that the mechanisms involved in cleavage of the various organophosphonates are similar, although recent evidence shows that, in Arthrobacter sp.…”