Repository for the manuscript: Bioremediation of glyphosate-contaminated soil with PGPB bacteria and their effect on soil microbiome changes interactions

Glyphosate contamination in soil is a significant environmental concern because of its persistence and potential negative impacts on ecosystems and represents a health risk to humans. Thus, effective remediation strategies are required. Plant growth-promoting bacteria (PGPB) are promising for mitigating glyphosate contamination in the soil. The aim of this study was to evaluate the capacity to degrade glyphosate (2000 mg kg-1) of three airborne PGPB isolates Exiguobacterium indicum AS03, Kocuria sediminis AS04 and Rhodococcus rhodochrous AS33, individually and in consortium (CS) (A03-As04-AS33) compared to natural attenuation (control soil) in microcosmos conditions. In addition, their effect on the soil microbiome changes the interactions and foil function. The AS03 strain showed significantly more degradation of glyphosate (86.3%) flowed by AS04 and AS33 strains at 14 days, with 61.6% and 64.7%, respectively. No significant differences were observed in the control (CTL) treatment. At 60 d, three strains showed degradation like that of the control (94.3%). Biodegradation was observed with bioaugmentation using the three strains in AMPA presence (from 24 to 49 mg kg-1) during the experiment, without significant differences between the three strains. The CTL treatment resulted in the accumulation of AMPA after seven days, with the highest concentration at 28 days (990 mg kg-1), suggesting that biodegradation was lower than that with bioaugmentation. It decreased to 397 mg kg-1 at 60 days. When the consortium (CS) was applied, an acceleration of glyphosate removal was observed at 7 days, decreasing to 153 mg kg-1 of glyphosate concentration compared to the control (CTL), which decreased to 294 mg kg-1. The CS treatment reached 99.7% glyphosate removal, whereas the control had 94% and 89.5% CS + MS at 60 days. The minimum AMPA concentration was detected in Cs and CS + MS. The application of PGPB led to significant shifts in soil microbial community structure. The abundance of Proteobacteria and Firmicutes increased, which enhanced the functional capacity of the soil for glyphosate degradation. Changes in microbial composition included increases in glyphosate-degrading genera, such as Psychrobacter and Lyzobacter, indicating improved soil resilience and fertility. These findings demonstrate the adaptability and robustness of soil ecosystems for bioremediation intervention. The application of PGPB presents an environmentally friendly approach for addressing glyphosate contamination in soil, offering a sustainable solution to mitigate the environmental impact of this herbicide and how it is known as a tool for soil fertility and plant promotion.