[Microbial degradation of glyphosate herbicides (review)].

This review analyzes the issues associated with biodegradation of glyphosate (N-(phosphonomethyl)glycine), one of the most widespread herbicides. Glyphosate can accumulate in natural environments and can be toxic not only for plants but also for animals and bacteria. Microbial transformation and mineralization ofglyphosate, as the only means of its rapid degradation, are discussed in detail. The different pathways of glyphosate catabolism employed by the known destructing bacteria representing different taxonomic groups are described. The potential existence of alternative glyphosate degradation pathways, apart from those mediated by C-P lyase and glyphosate oxidoreductase, is considered. Since the problem of purifying glyphosate-contaminated soils and water bodies is a topical issue, the possibilities of applying glyphosate-degrading bacteria for their bioremediation are discussed.

[Sorption and microbial degradation of glyphosphate in soil suspensions].

Sorption and microbial destruction of glyphosphate, the active agent of the herbicide Groundbio, in suspensions of sod-podzolic and gray forest soils has been studied. According to the values of the adsorptive capacity (3560 and 8200 mg/kg, respectively) and the Freundlich constants (Kf, 15.6 and 18.7, respectively), these soils had a relatively high sorption capacity as related to the herbicide. Sorbed glyphosphate is represented by extractable and bound (inextractable) fractions. After long-term incubation of sterile suspensions, the ratio of these fractions reached 2 : 1 for sod-podzolic soil and 1 : 1 for gray forest soil. Inoculation of a native suspension of sod-podzolic soil with cells of a selected degrader strain Ochrobactum anthropi GPK 3 resulted in a 25.4% decrease in the total glyphosphate content (dissolved and extractable), whereas in a noninoculated suspension, the loss did not exceed 5.5%. The potential for the use of a selected bacterial strain for intensification of the glyphosphate destruction processes in soil systems is demonstrated for the first time.

[Microbial degradation of organophosphonates by soil bacteria].

Bacteria that can utilize glyphosate (GP) or methylphosphonic acid (MPA) as a sole phosphorus source have been isolated from soil samples polluted with organophosphonates (OP). No matter which of these compounds was predominant in the native habitat of the strains, all of them utilized methylphosphonate. Some of the strains isolated from GP-polluted soil could utilize both phosphorus sources. Strains growing on glyphosate only were not isolated. The isolates retained high destructive activity after long-term storage of cells in lyophilized state, freezing to -20 degrees C, and maintenance on various media under mineral oil. When phosphorus-starved cells (with 2% phosphorus) were used as inoculum, the efficiency of OP biodegradation significantly increased (1.5-fold).