Anaerobic degradation of organic carbon supports uncultured microbial populations in estuarine sediments

Microbiome

Research

Kai-Uwe Hinrichs¹  Marcus Elvert¹  Weichao Wu²  Fengping Wang³  Tiantian Yu³  Jialin Hou⁴  Wenyue Liang⁴  Yunru Chen⁴  Yinzhao Wang⁴ 

[1]Organic Geochemistry Group, MARUM-Center for Marine Environmental Sciences, University of Bremen, 28359, Bremen, Germany

[2]Faculty of Geosciences, University of Bremen, 28359, Bremen, Germany

[3]Organic Geochemistry Group, MARUM-Center for Marine Environmental Sciences, University of Bremen, 28359, Bremen, Germany

[4]Faculty of Geosciences, University of Bremen, 28359, Bremen, Germany

[5]Shanghai Engineering Research Center of Hadal Science and Technology, College of Marine Science, Shanghai Ocean University, 201306, Shanghai, China

[6]School of Oceanography, Shanghai Jiao Tong University, 200240, Shanghai, China

[7]State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 200240, Shanghai, China

[8]State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 200240, Shanghai, China

关键词: Estuarine sediment;    Organic carbon;    Anaerobic degradation;    Uncultured bacteria;    Acetogenesis;   

DOI  :  10.1186/s40168-023-01531-z

 received in 2022-08-31, accepted in 2023-03-22,  发布年份 2023

来源: Springer

【 摘 要 】

BackgroundA large proportion of prokaryotic microbes in marine sediments remains uncultured, hindering our understanding of their ecological functions and metabolic features. Recent environmental metagenomic studies suggested that many of these uncultured microbes contribute to the degradation of organic matter, accompanied by acetogenesis, but the supporting experimental evidence is limited.ResultsEstuarine sediments were incubated with different types of organic matters under anaerobic conditions, and the increase of uncultured bacterial populations was monitored. We found that (1) lignin stimulated the increase of uncultured bacteria within the class Dehalococcoidia. Their ability to metabolize lignin was further supported by the presence of genes associated with a nearly complete degradation pathway of phenolic monomers in the Dehalococcoidia metagenome-assembled genomes (MAGs). (2) The addition of cellulose stimulated the increase of bacteria in the phylum Ca. Fermentibacterota and family Fibrobacterales, a high copy number of genes encoding extracellular endoglucanase or/and 1,4-beta-cellobiosidase for cellulose decomposition and multiple sugar transporters were present in their MAGs. (3) Uncultured lineages in the order Bacteroidales and the family Leptospiraceae were enriched by the addition of casein and oleic acid, respectively, a high copy number of genes encoding extracellular peptidases, and the complete β-oxidation pathway were found in those MAGs of Bacteroidales and Leptospiraceae, respectively. (4) The growth of unclassified bacteria of the order Clostridiales was found after the addition of both casein and cellulose. Their MAGs contained multiple copies of genes for extracellular peptidases and endoglucanase. Additionally, 13C-labeled acetate was produced in the incubations when 13C-labeled dissolved inorganic carbon was provided.ConclusionsOur results provide new insights into the roles of microorganisms during organic carbon degradation in anaerobic estuarine sediments and suggest that these macro and single molecular organic carbons support the persistence and increase of uncultivated bacteria. Acetogenesis is an additional important microbial process alongside organic carbon degradation.8vg1mZsw3sS2b3Wiiq9h8HVideo Abstract

【 授权许可】

CC BY   
© The Author(s) 2023

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