optimization of phenanthrene-degradation by dietzia cinnamea ap for bioremediation applications

background: this study focused on isolation and identification of a phenanthrene (phe) degrader bacterium and optimization of environmental conditions for phe degradation. materials and methods: enrichment technique was used for isolation and the most effective isolate, named ap, selected based on its phe biodegradation abilities. the isolate was identified using morphological and biochemical tests as well as16s rdna sequencing. the effects of various factors such as temperature, ph and c/n on bacterial growth and phe degradation were investigated using protein assay (bradford) and gas chromatography (gc), respectively. results: the selected isolate was identified as dietzia cinnamea ap. it was able to degrade phe at ph 6-10 (optimum at 8), temperatures of 25 -45 °c (optimum at 35 °c) and nh4cl concentrations of 0.5-2.5 gl-1 (optimum at 2 g l-1). by optimization of environmental parameters, phe degradation rate was increased more than 1.2 fold (from 60% to 73%) within 10 days of fermentation. conclusion:  d. cinnamea ap was shown to be an appropriate candidate for bioremediation applications. to our knowledge, this is the first report of d. cinnamea species that degrade phe.