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

Abstract

Alachlor, an aniline herbicide widely used in corn production, is frequently detected in water resources. The main objectives 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 of using bacterial consortium in soil culture. Kavar corn field soil with a long history of alachlor application in Fars province of Iran has been explored for their potential of alachlor biodegradation. The influence of different carbon compounds (glucose, sodium citrate, sucrose, starch and the combination of these compounds), the effect of nitrogen sources (ammonium nitrate and urea) and different pH (5.5-8.5) on alachlor removal efficiency by the bacterial consortium in liquid culture were investigated. After a multi-step enrichment program 100 days of acclimation, a culture with the high capability of alachlor degradation was obtained (63%). Glucose and sodium citrate had the highest alachlor reduction rate (85%). Alachlor reduction rate increased more rapidly by the addition of ammonium nitrate (94%) compare to urea. Based on the data obtained in the present study, pH of 7.5 is optimal for alachlor biodegradation. After 30 days of incubation, the percent of alachlor reduction were significantly enhanced in the inoculated soils (74%) as compared to uninoculated control soils (17.67%) at the soil moisture content of 25%. In conclusion, bioaugmentation of soil with bacterial consortium may enhance the rate of alachlor degradation in a polluted soil.

Optimization of Atrazine Degradation in the Aqueous Phase Using Titanium Catalyst Doped With Iron (Fe+3-TiO2) Processes

“…Dehghani et al demonstrated that this phenomenon may be related to atrazine photo degradation when its exposure time to the UV-A radiation is increased, and that a greater oxidation reaction occurs in the presence of hydroxyl radicals (32). In fact, the reaction rate at equilibrium reached a plateau.…”

Impact of bioaugmentation of soil with n-hexadecane-degrading bacteria and phosphorus source on the rate of biodegradation in a soil-slurry system

“…Bacillus subtilis in a soil-slurry system exhibited the maximum removal efficiency with the highest influence on its biological activity. The pH is one of the important parameters affecting cells' metabolism and enzymes function (Dehghani M. et al, 2013). So, pH variations during the incubation period are indicative of biological reactions.…”

“…Bioremediation is a remedial approach treating the contaminated soil with the advantages of simplicity, costeffective and environmentally friendly technology (Vidali M., 2001;Dehghani M. et al, 2013;Wang S. et al, 2016). But this method has some disadvantages such as long treatment time (Cha D.K.…”

“…Biostimulation is also used to remove total petroleum hydrocarbons (TPH) from polluted soil (Alvarez and Illman, 2006). Many studies showed that the addition of phosphorus and nitrogen sources to soil may enhance the biodegradation of hydrocarbons (Graham D. et al, 1999;Dehghani et al, 2013). The application of the phosphorus sources increased the rate of biodegradation up to 8.5% (Adetutu E.M. et al, 2012).…”

Degradation rates of alachlor, atrazine and bentazone in the profiles of Polish Luvisols

“…It undergoes weak sorption in soil (organic carbon normalized adsorption coefficient K OC = 33-742 cm 3 g -1 , Wauchope et al, 1992) and can leach to surface water and groundwater (Spalding et al, 2003;Vryzas et al, 2012). Alachlor can undergo chemical decomposition (Chou, 1977) and photodegradation in soil (Fang, 1979), but microbial degradation DT 50 -50% disappearance time) (Tomlin, 2006) has the greatest practical relevance (Dehghani et al, 2013). Bentazone is a benzothiadiazine herbicide for controlling dicotyledonous weeds.…”