Robust linuron degradation in on-farm biopurification systems exposed to sequential environmental changes

Area of Science:

• Environmental Microbiology
• Bioremediation
• Agricultural Science

Background:

• On-farm biopurification systems (BPS) utilize biodegradation to treat pesticide-contaminated wastewater.
• Pesticide-primed soil enhances the establishment of pesticide-degrading microbial populations in BPS.
• Limited data exist on the robustness of these microbial communities under suboptimal farm conditions.

Purpose of the Study:

• To investigate the response of linuron-mineralizing microbiota in BPS microcosms to environmental stressors.
• To compare the resilience of microbial communities from linuron-primed versus non-primed soil under stress.
• To assess the recovery capacity of these communities after stress periods.

Main Methods:

• BPS microcosms were inoculated with either linuron-primed or non-primed soil.
• Microcosms were subjected to a sequence of stress conditions: no linuron supply, drought, cold periods, and pesticide mixture feeding.
• Linuron mineralization capacity and microbial community dynamics, particularly Variovorax phylotypes, were monitored.

Main Results:

• Periods without linuron supply or drought significantly reduced the linuron-mineralizing community size in both setups.
• The non-primed soil setup showed a complete loss of linuron degradation capacity when linuron supply ceased.
• Linuron mineralization rapidly recovered in both systems upon restoring normal conditions; cold periods and pesticide mixtures had no adverse effect.

Conclusions:

• The pesticide-mineralizing microbial community in BPS is robust and resilient to environmental stress conditions commonly encountered on farms.
• Primed soil enhances community stability, though non-primed systems also demonstrate rapid recovery post-stress.
• BPS demonstrate a reliable capacity for pesticide degradation, even when facing environmental challenges and subsequent restoration of optimal conditions.