Structure of hydrocarbonoclastic nitrate-reducing bacterial communities in bioturbated coastal marine sediments

M. Stauffert (1) , Cristiana Cravo-Laureau (2) , Robert Duran (2)

1 UBP - Université Blaise Pascal - Clermont-Ferrand 2
2 IPREM - Institut des sciences analytiques et de physico-chimie pour l'environnement et les materiaux

The organisation of denitrifying microorganisms in oil-polluted bioturbated sediments was investigated in mesocosms under conditions as closer as possible to that observed in the environment. Molecular and culture-dependent approaches revealed that denitrifying Gammaproteobacteria were abundant in oil-polluted and bioturbated sediments suggesting that they may play a key role in hydrocarbon degradation in the environment. T-RFLP and gene libraries analyses targeting nirS gene showed that denitrifying microbial communities structure was slightly affected by either the addition of Hediste diversicolor or crude oil revealing the metabolic versatility of denitrifying microorganisms. From oil-polluted sediments, distinct denitrifying hydrocarbonoclastic bacterial consortia were obtained by enrichment cultures on high molecular weight polyaromatic hydrocarbons (PAHs) (dibenzothiophene, fluoranthene, pyrene and chrysene) under nitrate-reducing conditions. Interestingly, molecular characterisation of the consortia showed that the denitrifying communities obtained from oiled microcosms with addition of H. diversicolor were different to that observed without H. diversicolor addition, especially with fluoranthene and chrysene revealing the bacterial diversity involved in the degradation of these PAHs. The manuscript describes the structure of denitrifying community during oil degradation in bioturbated marine sediments, by molecular and culture-dependent approaches.

Mots clés: Bacteria; Bacteria (microorganisms); Bioturbation; classification; Cultivable bacteria; Gammaproteobacteria; genetics; Geologic Sediments; Hydrocarbon; Hydrocarbons; isolation and purification; metabolism; microbiology; nirS gene; Nitrates; nitric acid derivative; nitrite reductase; Nitrite Reductases; oil spill; PAH biodegradation; Petroleum pollution; phylogeny; Polymorphism; Restriction Fragment Length; restriction fragment length polymorphism; sediment; T-RFLP

Domaines: Chimie

M. Stauffert, Cristiana Cravo-Laureau, Robert Duran. Structure of hydrocarbonoclastic nitrate-reducing bacterial communities in bioturbated coastal marine sediments. FEMS Microbiology Ecology, 2014, 89 (3), pp.580--593. ⟨10.1111/1574-6941.12359⟩. ⟨hal-01495820⟩