TY - JOUR
T1 - Novel hydrocarbon-utilizing soil mycobacteria synthesize unique mycocerosic acids at a Sicilian everlasting fire
AU - Smit, Nadine T.
AU - Villanueva, Laura
AU - Rush, Darci
AU - Grassa, Fausto
AU - Witkowski, Caitlyn R.
AU - Holzheimer, Mira
AU - Minnaard, Adriaan J.
AU - Sinninghe Damsté, Jaap S.
AU - Schouten, Stefan
N1 - Funding Information:
Financial support. Stefan Schouten, Laura Villanueva and Jaap S. Sinninghe Damsté have been supported by the Netherlands Earth System Science Center (NESSC) and the Soehngen Institute for Anaerobic Microbiology (SIAM) through Gravitation grants (grant nos. 024.002.001 and 024.002.002) from the Dutch Ministry for Education, Culture and Science.
Publisher Copyright:
© 2021 Copernicus GmbH. All rights reserved.
PY - 2021/3/1
Y1 - 2021/3/1
N2 - Soil bacteria rank among the most diverse groups of organisms on Earth and actively impact global processes of carbon cycling, especially in the emission of greenhouse gases like methane, CO2 and higher gaseous hydrocarbons. An abundant group of soil bacteria are the mycobacteria, which colonize various terrestrial, marine and anthropogenic environments due to their impermeable cell envelope that contains remarkable lipids. These bacteria have been found to be highly abundant at petroleum and gas seep areas, where they might utilize the released hydrocarbons. However, the function and the lipid biomarker inventory of these soil mycobacteria are poorly studied. Here, soils from the Fuoco di Censo seep, an everlasting fire (gas seep) in Sicily, Italy, were investigated for the presence of mycobacteria via 16S rRNA gene sequencing and fatty acid profiling. The soils contained high relative abundances (up to 34% of reads assigned) of mycobacteria, phylogenetically close to the Mycobacterium simiae complex and more distant from the wellstudied M. tuberculosis and hydrocarbon-utilizing M. paraffinicum. The soils showed decreasing abundances of mycocerosic acids (MAs), fatty acids unique for mycobacteria, with increasing distance from the seep. The major MAs at this seep were tentatively identified as 2,4,6,8-tetramethyl tetracosanoic acid and 2,4,6,8,10-pentamethyl hexacosanoic acid. Unusual MAs with mid-chain methyl branches at positions C-12 and C-16 (i.e., 2,12-dimethyl eicosanoic acid and 2,4,6,8,16-pentamethyl tetracosanoic acid) were also present. The molecular structures of the Fuoco di Censo MAs are different from those of the well-studied mycobacteria like M. tuberculosis or M. bovis and have relatively 13C-depleted values (38a to48), suggesting a direct or indirect utilization of the released seep gases like methane or ethane. The structurally unique MAs in combination with their depleted-13C values identified at the Fuoco di Censo seep offer a new tool to study the role of soil mycobacteria as hydrocarbon gas consumers in the carbon cycle.
AB - Soil bacteria rank among the most diverse groups of organisms on Earth and actively impact global processes of carbon cycling, especially in the emission of greenhouse gases like methane, CO2 and higher gaseous hydrocarbons. An abundant group of soil bacteria are the mycobacteria, which colonize various terrestrial, marine and anthropogenic environments due to their impermeable cell envelope that contains remarkable lipids. These bacteria have been found to be highly abundant at petroleum and gas seep areas, where they might utilize the released hydrocarbons. However, the function and the lipid biomarker inventory of these soil mycobacteria are poorly studied. Here, soils from the Fuoco di Censo seep, an everlasting fire (gas seep) in Sicily, Italy, were investigated for the presence of mycobacteria via 16S rRNA gene sequencing and fatty acid profiling. The soils contained high relative abundances (up to 34% of reads assigned) of mycobacteria, phylogenetically close to the Mycobacterium simiae complex and more distant from the wellstudied M. tuberculosis and hydrocarbon-utilizing M. paraffinicum. The soils showed decreasing abundances of mycocerosic acids (MAs), fatty acids unique for mycobacteria, with increasing distance from the seep. The major MAs at this seep were tentatively identified as 2,4,6,8-tetramethyl tetracosanoic acid and 2,4,6,8,10-pentamethyl hexacosanoic acid. Unusual MAs with mid-chain methyl branches at positions C-12 and C-16 (i.e., 2,12-dimethyl eicosanoic acid and 2,4,6,8,16-pentamethyl tetracosanoic acid) were also present. The molecular structures of the Fuoco di Censo MAs are different from those of the well-studied mycobacteria like M. tuberculosis or M. bovis and have relatively 13C-depleted values (38a to48), suggesting a direct or indirect utilization of the released seep gases like methane or ethane. The structurally unique MAs in combination with their depleted-13C values identified at the Fuoco di Censo seep offer a new tool to study the role of soil mycobacteria as hydrocarbon gas consumers in the carbon cycle.
UR - http://www.scopus.com/inward/record.url?scp=85101958587&partnerID=8YFLogxK
U2 - 10.5194/bg-18-1463-2021
DO - 10.5194/bg-18-1463-2021
M3 - Article
SN - 1726-4170
VL - 18
SP - 1463
EP - 1479
JO - Biogeosciences
JF - Biogeosciences
IS - 4
ER -