Phenylurea Herbicide Biodegradation in Aqueous Solution using bioaugmentation strategies with Advenella sp. JRO

Phenylureas are among the most widely used herbicide families worldwide for weed control. However, the mobility of these compounds and their degradation metabolites poses risks to animals, plants, aquatic invertebrates, microbial communities, and humans. Advenella sp. JRO (AFQG01000022) has previously been identified as an efficient biodegrader of diuron, the most commonly used phenylurea herbicide. Building on this knowledge, the aim of the present study was to evaluate the potential of this strain to degrade other widely used phenylurea herbicides: chlorotoluron, isoproturon, fluometuron, and linuron. HPLC-UV methodology for pesticide detection in solution showed the limited biodegradation capacity of this strain, achieving only 28, 40, 42 and 59 % degradation rate of solutions with 10mgL^-1 as single initial concentration of chlorotoluron, isoproturon, linuron and fluometuron, respectively, and with very high DT₅₀ according to kinetic models (range 342-3636 days), so Advenella sp. JRO cannot be considered as a valid method to biodegrade these phenylureas.

To enhance degradation rate, Advenella sp. JRO was also tested as part of consortia with Arthrobacter sp. N2 (AF235091) and Variovorax sp. SRS16 (DQ432053), two strains that previously had shown toxicity reductions and mineralization increases in diuron-contaminated soils by removing toxic metabolites. When these strains were combined, biodegradation significantly improved. The consortium composed of Advenella sp. JRO and Variovorax sp. SRS16 achieved 84% and 96% degradation (DT₅₀: 3 and 7 days) of chlorotoluron and fluometuron, respectively. Similarly, the triad formed by Advenella sp. JRO, Variovorax sp. SRS16, and Arthrobacter sp. N2 degraded 98% of isoproturon (DT₅₀: 7 days).

This study demonstrates, for the first time, the ability of Advenella sp. JRO to degrade chlorotoluron, fluometuron, isoproturon, and linuron. Furthermore, the engineered consortium formed with Arthrobacter sp. N2 and Variovorax sp. SRS16 represents a promising strategy for improving bioaugmentation protocols aimed at the bioremediation of soils contaminated with phenylurea herbicides.