SODIUM BENZOATE ASSIMILATION BY RHODOCOCCUS AETHERIVORANS UCM AC-602

Sodium benzoate (SB) is a widely used preservative (E211) and also serves as an active ingredient in several pharmaceuticals. Prolonged exposure to SB can disrupt aquatic ecosystems, adversely affecting aquatic organisms and potentially human health. Aim. To investigate the features of sodium benzoate biodegradation by the Rhodococcus aetherivorans UCM Ac-602 strain and assess the ecological safety of the toxicant and its degradation products for higher plants. Methods. The concentration of SB was determined using high-performance liquid chromatography. Fatty acids composition was analyzed by gas chromatography–mass spectrometry. Catalase activity was measured spectrophotometrically, and cell membrane permeability was assessed using crystal violet. Phytotoxicity was evaluated via a rapid assay using wheat (Triticum aestivum L.) as a test plant. Results. The R. aetherivorans UCM Ac-602 fully utilized 0.5 g/L of SB within 7 days. A twofold decrease in the C18:1 cis-9 fatty acid and a 1.7-fold increase in 10Me-C18:0 were observed during growth on SB. Changes in catalase activity and membrane permeability during SB assimilation contributed to cellular protection against the toxic effects of the substrate. Neither SB nor its metabolites exhibited phytotoxic properties. Conclusions. The main mechanisms of adaptation of R. aetherivorans UCM Ac-602 to SB assimilation are modifications in fatty acid profiles, changes in catalase activity, and alterations in membrane permeability. SB and its degradation products were shown to be non-phytotoxic and safe for plant development.