Biodegradation of alachlor in liquid and soil cultures under variable carbon and nitrogen sources by bacterial consortium isolated from corn field soil

Alachlor, an aniline herbicide widely used in corn production, is frequently detected in water resources. the mainobjectives of this research were focused on isolating bacterial consortium capable of alachlor biodegradation,assessing the effects of carbon and nitrogen sources on alachlor biodegradation and evaluating the feasibility ofusing bacterial consortium in soil culture. kavar corn field soil with a long history of alachlor application in farsprovince of iran has been explored for their potential of alachlor biodegradation. the influence of different carboncompounds (glucose, sodium citrate, sucrose, starch and the combination of these compounds), the effect ofnitrogen sources (ammonium nitrate and urea) and different ph (5.5-8.5) on alachlor removal efficiency by thebacterial consortium in liquid culture were investigated. after a multi-step enrichment program 100 days ofacclimation, a culture with the high capability of alachlor degradation was obtained (63%). glucose and sodiumcitrate had the highest alachlor reduction rate (85%). alachlor reduction rate increased more rapidly by the additionof ammonium nitrate (94%) compare to urea. based on the data obtained in the present study, ph of 7.5 is optimalfor alachlor biodegradation. after 30 days of incubation, the percent of alachlor reduction were significantlyenhanced in the inoculated soils (74%) as compared to uninoculated control soils (17.67%) at the soil moisturecontent of 25%. in conclusion, bioaugmentation of soil with bacterial consortium may enhance the rate of alachlordegradation in a polluted soil.