eng Science and Education Publishing International Journal of Environmental Bioremediation & Biodegradation 2333-8636 2015-05-17 3 2 40 47 10.12691/ijebb-3-2-1 IJEBB2015321 article Aniefiok E. Ite aniefiokite@yahoo.co.uk 1 2 3 Nicola F. Hanney 3 Kirk T. Semple 3 Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ, United Kingdom The effect of hydroxycinnamic acids (caffeic, ferulic and p-coumaric acids) on the microbial mineralisation of phenanthrene in soil slurry by the indigenous microbial community has been investigated. The rate and extent of 14C-phenanthrenemineralisation in artificially spiked soils were monitored in the absence of hydroxycinnamic acids and presence of hydroxycinnamic acids applied at three different concentrations (50, 100 and 200 µg kg-1) either as single compounds or as a mixture of hydroxycinnamic acids (caffeic, ferulic and p-coumaric acids at a 1:1:1 ratio). The highest extent of 14C-phenanthrene mineralisation (P< 0.001) was obtained in soils amended with 50 µg kg-1 ferulic acid (52.9% ± 0.45) compared to that obtained in unamended soils (37.2% ± 0.23). In addition, mineralisation of 14C-phenanthrene was monitored in pre-incubated artificially spiked soils at various time intervals (0, 16, 32 and 48 d) following amendment with hydroxycinnamic acids at a concentration of 100 µg kg-1. After 16 d of pre-exposure, artificially spiked soils amended with 100 µg kg-1 ferulic acids had the highest extents of 14C-phenanthrene mineralisationcompared to those obtained soils with other treatment conditions. The results obtained showed enhanced mineralisation of 14C-phenanthrene in freshly spiked soils amended with hydroxycinnamic acids and the extents of 14C-phenanthrene mineralisation range in the order of 50 ≥ 100 > 200 µg kg-1. Depending on its concentrationin soil, hydroxycinnamic acids can either stimulate or inhibit mineralisation of phenanthrene by indigenous soil microbial community. Therefore, effective understanding of phytochemical-microbe-organic contaminant interactions is essential for further development of phytotechnologies for remediation of PAH-contaminated soils. http://pubs.sciepub.com/ijebb/3/2/1/ijebb-3-2-1.pdf microbial mineralization phenanthrene hydroxycinnamic acids caffeic acid ferulic acid p-coumaric acid soil