Authors: Jie Liu Shaohua Chen Jie Ding Ying Xiao Haitao Han Guohua Zhong
Publish Date: 2015/09/04
Volume: 99, Issue: 24, Pages: 10839-10851
Abstract
The degrading microorganisms isolated from environment usually fail to degrade pollutants when used for bioremediation of contaminated soils thus additional treatments are needed to enhance biodegradation In the present study the potential of sugarcane bagasse as bacteriaimmobilizing support was investigated in mesotrione biodegradation A novel isolate Bacillus pumilus HZ2 was applied in bacterial immobilization which was capable of degrading over 95 of mesotrione at initial concentrations ranging from 25 to 200 mg L−1 within 4 days in flaskshaking tests Scanning electron microscope SEM images showed that the bacterial cells were strongly absorbed and fully dispersed on bagasse surface after immobilization Specially 865 and 829 of mesotrione was eliminated by bacteria immobilized on bagasse of 100 and 60 mesh respectively which indicated that this immobilization was able to maintain a high degrading activity of the bacteria Analysis of the degradation products determined 2amino4methylsulfonylbenzoic acid AMBA and 4methylsulfonyl2nitrobenzoic acid MNBA as the main metabolites in the biodegradation pathway of mesotrione In the sterile soil approximately 90 of mesotrione was degraded after supplementing 50 of molasses in bacteriabagasse composite which greatly enhanced microbial adaptability and growth in the soil environment In the field tests over 75 of mesotrione in soil was degraded within 14 days The immobilized preparation demonstrated that mesotrione could be degraded at a wide range of pH values 50–80 and temperatures 25–35 °C especially at low concentrations of mesotrione 5 to 20 mg kg−1 These results showed that sugarcane bagasse might be a good candidate as bacteriaimmobilizing support to enhance mesotrione degradation by Bacillus p HZ2 in contaminated soils
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