Impacts of carbon sources on simazine biodegradation by Arthrobacter strain SD3-25 in liquid culture and soil microcosm

High concentrations of s-triazine herbicides might occur in soils at spill sites. Selection of a degrader or consortium with high degradation ability is of practical importance to quickly clean up the heavy contamination. However, survival of inoculated degraders might be affected by the abundance of organic matter in soil. In this study, a simazine-degrading bacterium, Arthrobacter sp. SD3-25, was isolated from an agricultural soil. The effects of carbon sources on the strain's growth and degradation ability in both liquid culture and soil microcosm were investigated. The results indicated that the strain had much higher simazine degradation ability than those reported in previous studies, and it could quickly clean up the heavy herbicide contamination in soil. Moreover, instead of having a negative impact, external carbon source could stimulate the strain's growth and enhance simazine biodegradation rate in both culture conditions. Sucrose amendment increased the proportions of simazine-degrading trzN, atzB and atzC genes in bioaugmented soil. Bioaugmentation with the strain SD3-25 could be an option for bioremediation of heavily s-triazine-contaminated soil. However, further studies are necessary in order to elucidate the impacts of various types of carbon sources on different degraders. (C) 2014 Elsevier Ltd. All rights reserved.