Anaerobic oxidation of petroleum hydrocarbons in enrichment cultures from sediments of the Gorevoy Utes natural oil seep under methanogenic and sulfate-reducing conditions

Abstract

This article presents the rst experimental data on the ability of microbial communities from sediments of the Gorevoy Utes natural oil seep to degrade petroleum hydrocarbons under anaerobic conditions. Like in marine ecosystems associated with oil discharge, available electron acceptors, in particular sulfate ions, affect the composition of the microbial community and the degree of hydrocarbon conversion. The cultivation of the surface sediments under sulfate-reducing conditions led to the formation of a more diverse bacterial community and greater loss of n-alkanes (28%) in comparison to methanogenic conditions (6%). Microbial communities of both surface and deep sediments are more oriented to degrade polycyclic aromatic hydrocarbons (PAHs), to which the degree of the PAH conversion testi es (up to 46%) irrespective of the present electron acceptors. Uncultured microorganisms with the closest homologues from thermal habitats, sediments of mud volcanoes and environments contaminated with hydrocarbons mainly represented microbial communities of enrichment cultures. The members of the phyla Firmicutes, Chloro exi, and Caldiserica (OP5), as well as the class Deltaproteobacteria and Methanomicrobia, were mostly found in enrichment cultures and belong to the "core" of microorganisms The in uence of gas-saturated uids may be responsible for the presence in the bacterial 16S rRNA gene libraries of the sequences of "rare taxa": Planctomycetes, Ca. Atribacteria (OP9), Ca. Armatimonadetes (OP10), Ca. Latescibacteria (WS3), Ca. division (AC1), Ca. division (OP11), and Ca. Parcubacteria (OD1), which can be involved in hydrocarbon oxidation.

Molecular Indicators of Sources and Biodegradation of Organic Matter in Sediments of Fluid Discharge Zones of Lake Baikal

“…Such distribution is a characteristic of the asphaltene fraction of crude oils [83] but was not found in fresh and biodegraded oils of lake Baikal where the content of HMW homologues n-C 30+ sharply decreases [84]. However, the presence of UCM, total absence of isoprenoids, high level of n-alkanes maturity (CPI ≤ 2; Table 2) and decrease of n-C 35 -n-C 39 homologues content with depth in the studied samples (site 8, 0-15, 50-60 cm) may indicate aerobic biodegradation processes which lead to the partial loss of lower MW and the preservation of higher MW n-alkanes [85].…”

“…Geosciences 2022, 12, 72 10 of 25 biodegradation processes which lead to the partial loss of lower MW and the preservation of higher MW n-alkanes [85]. Isoprenoid HCs (pristane and phytane) are detected in all samples, except surface sediments of Gorevoy Utes (site 8), and their content reaches maximum values for the region in the deeper layers of site 7 (100-120 cm) and 8 (60-70 cm).…”

Metabolic profiling of petroleum-degrading microbial communities incubated under high-pressure conditions

“…Many reports have demonstrated the biodegradation of petroleum hydrocarbons under nitrate-, ferric-, and sulfatereducing conditions (Shin et al, 2019;Zhang et al, 2019;Pavlova et al, 2022); when these electron acceptors are depleted, the hydrocarbons can be further converted into methane and carbon dioxide (Jones et al, 2008;Mbadinga et al, 2012;Ma et al, 2017;Liu et al, 2019). Sulfate-reducing prokaryotes (SRPs) were the first microorganisms reported in oil reservoirs (Bastin et al, 1926).…”

How to simply and efficiently screen microbial strains capable of anaerobic biosynthesis of biosurfactants: Method establishment, influencing factors and application example evaluation

“…These studies confirmed the feasibility of screening the microorganisms which can anaerobically biosynthesize biosurfactants from the natural environments. In oil reservoirs, sediment and other anoxic environments, the anoxic conditions resulted in the inner microbial communities with unique metabolic function (Zhao et al, 2021 ; Pavlova et al, 2022 ). Due to the nutrients chemotaxis and the evolutionary adaptation to hydrophobic substrates, there exist microorganisms capable of metabolizing petroleum hydrocarbons in oil reservoirs, oily sludge and the oil-polluted soil and water (Rodríguez et al, 2021 ; Zhao et al, 2021 ; Pavlova et al, 2022 ).…”

“…In oil reservoirs, sediment and other anoxic environments, the anoxic conditions resulted in the inner microbial communities with unique metabolic function (Zhao et al, 2021 ; Pavlova et al, 2022 ). Due to the nutrients chemotaxis and the evolutionary adaptation to hydrophobic substrates, there exist microorganisms capable of metabolizing petroleum hydrocarbons in oil reservoirs, oily sludge and the oil-polluted soil and water (Rodríguez et al, 2021 ; Zhao et al, 2021 ; Pavlova et al, 2022 ). And most of these microorganisms can produce biosurfactants to assist the biodegradation petroleum hydrocarbons through emulsifying and solubilizing petroleum hydrocarbons (Patowary et al, 2017 ; Phetcharat et al, 2019 ; Atakpa et al, 2022 ).…”