Bioremediation of 4-chloroaniline and 3,4-dichloroaniline contaminated soil under copper fungicide co-contamination

Abstract

4-chloroaniline and 3,4-dichloroaniline have been widely used in many production processes of industries such as dye, rubbers, pharmaceutical products, pesticides and herbicides. Besides, 4CA and 3,4-DCA are the main intermediates of herbicide degradation by microorganisms. Due to their toxicity and recalcitrant in environment, bioremediation technique is necessary to reduce and clean up them. In liquid medium, addition of nutrients from natural sources inhibited 4CA degradation of Acinetobacter baylyi strain GFJ2 but enhanced 3,4-DCA biodegradation. Moreover, the addition copper fungicides (5, 10, 50 and 100 ppm) inhibited biodegradation of 4CA by A. baylyi strain GFJ2. Some copper fungicides (copper sulfate, copina-85, copinahydroxide and bordeaux-M) at low concentrations (5 and 10 ppm) enhanced 3,4-DCA biodegradation. Bioremediation including natural attenuation, biostimulation and bioaugmentation with 1) A. baylyi strain GFJ2; 2) A. baylyi strain GFJ2 and supplementary nutrients and 3) combination of A. baylyi strain GFJ2 and natural bacterial consortium from fertilizer were carried out to degrade 500 ppm CAs in two soils. In S3 soil, the highest CAs degradation was observed after 4 week treatment with the bioaugmentation having a combination of A. baylyi strain GFJ2 and natural bacterial consortium. For S5 soil, there was no difference of CAs degradation in each treatment. Biodegradation of CAs with and without copper sulfate (150 ppm) co-contamination was not different. The bacterial community during each treatment was monitored using the denaturing gradient gel electrophoresis (DGGE). The result showed that bacteria community in each treatment was changed and some bacteria were adapted and recovered. From DGGE result showed that A. baylyi strain GFJ2 could not survive in soil.