CHARACTERIZATION OF BURKHOLDERIA SP XTB-5 FOR PHENOL DEGRADATION AND PLANT GROWTH PROMOTION AND ITS APPLICATION IN BIOREMEDIATION OF CONTAMINATED SOIL

A key issue when researching land degradation is the pollution of soils. For bioremediation of contaminated soil, Burkholderia sp. XTB-5 cells were obtained from soil and grown on mineral salt medium with initial phenol concentrations of 650 mg L-1 and 850 mg L-1, which were found to degrade more than 98% of phenol content in less than 4 days. About 90% of phenol content (with initial concentration of 250 mg kg(-1) soil) was removed from soil inoculated with XTB-5 cells in 6 days. More than 90% of phenol content was removed within 20 days after co-introduction of XTB-5 cells and plants to sterilized soil in a greenhouse or to natural soil in field trials. But under the same conditions, individual introduction of plants to sterilized soil in the greenhouse reduced phenol content by about 50% and introduction to natural soil in field trials reduced phenol content by about 38%, suggesting that phytoremediation of phenol is often inefficient and microorganisms can efficiently degrade this pollutant. In addition, strain XTB-5 was found to solubilize phosphate and produce 1-Aminocyclopropane-1-Carboxylate (ACC) deaminase and siderophore. Strain XTB-5 promoted plant growth in both phenol-absent and phenol-spiked soil under greenhouse and field conditions. Considering that ACC deaminase is beneficial to plant growth under adverse environmental conditions, plant growth promotion by XTB-5 in phenol-contaminated soil is not only due to XTB-5 cell-degradation of phenol and reduced phytotoxicity but also to production of ACC deaminase. Hence, Burkholderia sp. XTB-5 presents an attractive microorganism for phytoremediation of contaminated soil and agronomic application. Copyright (C) 2016 John Wiley & Sons, Ltd.