%A Gutierrez,Tony %A Biddle,Jennifer F. %A Teske,Andreas %A Aitken,Michael D. %D 2015 %J Frontiers in Microbiology %C %F %G English %K Guaymas basin,hydrocarbon degradation,stable isotope probing,polycyclic aromatic hydrocarbons (PAHs),Cycloclasticus,deep sea,marine environment %Q %R 10.3389/fmicb.2015.00695 %W %L %M %P %7 %8 2015-July-07 %9 Original Research %+ Tony Gutierrez,Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC,USA,tony.gutierrez@hw.ac.uk %+ Tony Gutierrez,School of Life Sciences, Heriot-Watt University, Edinburgh,UK,tony.gutierrez@hw.ac.uk %# %! Hydrocarbon-degrading bacteria from Guaymas Basin %* %< %T Cultivation-dependent and cultivation-independent characterization of hydrocarbon-degrading bacteria in Guaymas Basin sediments %U https://www.frontiersin.org/articles/10.3389/fmicb.2015.00695 %V 6 %0 JOURNAL ARTICLE %@ 1664-302X %X Marine hydrocarbon-degrading bacteria perform a fundamental role in the biodegradation of crude oil and its petrochemical derivatives in coastal and open ocean environments. However, there is a paucity of knowledge on the diversity and function of these organisms in deep-sea sediment. Here we used stable-isotope probing (SIP), a valuable tool to link the phylogeny and function of targeted microbial groups, to investigate polycyclic aromatic hydrocarbon (PAH)-degrading bacteria under aerobic conditions in sediments from Guaymas Basin with uniformly labeled [13C]-phenanthrene (PHE). The dominant sequences in clone libraries constructed from 13C-enriched bacterial DNA (from PHE enrichments) were identified to belong to the genus Cycloclasticus. We used quantitative PCR primers targeting the 16S rRNA gene of the SIP-identified Cycloclasticus to determine their abundance in sediment incubations amended with unlabeled PHE and showed substantial increases in gene abundance during the experiments. We also isolated a strain, BG-2, representing the SIP-identified Cycloclasticus sequence (99.9% 16S rRNA gene sequence identity), and used this strain to provide direct evidence of PHE degradation and mineralization. In addition, we isolated Halomonas, Thalassospira, and Lutibacterium sp. with demonstrable PHE-degrading capacity from Guaymas Basin sediment. This study demonstrates the value of coupling SIP with cultivation methods to identify and expand on the known diversity of PAH-degrading bacteria in the deep-sea.