Microbial community responses to different volatile petroleum hydrocarbon class mixtures in an aerobic sandy soil.

Volatile Petroleum Hydrocarbon (VPH) class effects on soil microbial composition were investigated using two next-generation sequencing (NGS) techniques - 454 pyrosequencing and ion torrent sequencing. Microbial activity was stimulated by adding different VPH compound classes to the sandy soil in comparison with live controls without VPH addition. Microbial community structure was significantly affected by the various VPH classes. At the genus level, Rhodococcus, Desulfosporosinus, Polaromonas, Mesorhizobium and Methylibium had the highest relative abundances in the straight-chain alkane (str-alk) treated soil as compared to the control (p < 0.05, 2 sample t-tests) while Pseudomonas was more dominant in the cyclic alkane (cyc-alk) contaminated soil. Pseudonocardia was significantly higher in relative abundance in the aromatic hydrocarbon (aro-H) treated batches as compared to the control (p < 0.05, 2 sample t-tests). A non-metric multidimensional scaling (NMDS) of the Bray Curtis similarity between microbial communities in the batches revealed at least 60% similarity for each treatment and also showed that VPH class was a statistically significant factor in shaping the bacterial communities in the soil treatments (Global R = 0.861, p < 0.01). The NGS platforms (454 GS Junior and Ion torrent) compared in this study did not appear to affect the outcomes of the microbial community structure and composition analysis.