Integrated microbial–organic strategy for carbofuran remediation: water-dispersible ochrobactrum granules with biogas slurry

This study evaluates an integrated bioaugmentation-biostimulation strategy for carbofuran remediation using Ochrobactrum intermedium formulated as water-dispersible granules (WDGs) in combination with biogas slurry (BGS). In minimal salt medium, O. intermedium degraded 92.2% of 100 mg L⁻¹ carbofuran within 120 h (k = 0.69 day⁻¹; t₁/₂ = 1 day). GC-MS identified carbofuran-7-phenol and monoethyl phthalate as key intermediates. The WDGs retained > 80% viability and ~ 94% degradation efficiency after six months at 30 °C. In aqueous systems, BGS enhanced WDG activity, enabling 99% degradation within 120 h. In soil microcosms, WDGs + BGS (T5) achieved 92.4% degradation in 30 days (t₁/₂ = 8.04 days), outperforming WDGs alone (61%, t₁/₂ = 21.7 days), BGS alone (42%, t₁/₂ = 38.5 days), and control (26%). The combined treatment also improved microbial persistence, soil nutrients, and tomato growth, with no phytotoxic effects. Overall, coupling microbial formulations with organic amendments provides a robust and sustainable solution for remediating carbofuran-contaminated soils.