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Co-occurrence of Methanosarcina mazei and Geobacteraceae in an iron (III)-reducing enrichment culture.

Zheng S, Zhang H, Li Y, Zhang H, Wang O, Zhang J, Liu F - Front Microbiol (2015)

Bottom Line: First, iron (III) reducers including Geobacteraceae were successfully enriched by 3-months successive culture on amorphous Fe(III) oxides as electron acceptor and acetate as electron donor.Remarkably, aggregates were successively formed in the enrichments after three transfers.The results revealed by RNA-based analysis demonstrate that the co-occurrence of Methanosarcina mazei and Geobacteraceae in an iron (III)-reducing enrichment culture.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences Yantai, China ; Key Laboratory of Coastal Biology and Biological Resources Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences Yantai, China.

ABSTRACT
Methanosaeta harundinacea and Methanosarcina barkeri, known as classic acetoclastic methanogens, are capable of directly accepting electrons from Geobacter metallireducens for the reduction of carbon dioxide to methane, having been revealed as direct interspecies electron transfer (DIET) in the laboratory co-cultures. However, whether their co-occurrences are ubiquitous in the iron (III)-reducing environments and the other species of acetoclastic methanogens such as Methanosarcina mazei are capable of DIET are still unknown. Instead of initiating the co-cultures with pure cultures, two-step cultivation was employed to selectively enrich iron (III)-reducing microorganisms in a coastal gold mining river, Jiehe River, with rich iron content in the sediments. First, iron (III) reducers including Geobacteraceae were successfully enriched by 3-months successive culture on amorphous Fe(III) oxides as electron acceptor and acetate as electron donor. High-throughput Illumina sequencing, terminal restriction fragment length polymorphism (T-RFLP) and clone library analysis based on 16S rRNA genes revealed that the enrichment cultures actively contained the bacteria belong to Geobacteraceae and Bacilli, exclusively dominated by the archaea belong to Methanosarcinaceae. Second, the enrichment cultures including methanogens and Geobacteraceae were transferred with ethanol as alternative electron donor. Remarkably, aggregates were successively formed in the enrichments after three transfers. The results revealed by RNA-based analysis demonstrate that the co-occurrence of Methanosarcina mazei and Geobacteraceae in an iron (III)-reducing enrichment culture. Furthermore, the aggregates, as close physical contact, formed in the enrichment culture, indicate that DIET could be a possible option for interspecies electron transfer in the aggregates.

No MeSH data available.


Location of the sampling points in the Jiehe (Jh) River watershed. The location of the sediment samples for this study is presented by solid circles (Zhang et al., 2014).
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Figure 1: Location of the sampling points in the Jiehe (Jh) River watershed. The location of the sediment samples for this study is presented by solid circles (Zhang et al., 2014).

Mentions: Sediment samples were collected in July 2013 from the Jiehe River (37°05′N-37°33′N, 120°08′E-120°38′E), which is located in the northwest part of the Jiaodong peninsula, China (Figure 1). The geochemical characteristics of stream water were described previously (Zhang et al., 2014). Surface sediment layer (0–5 cm) and the pore water samples were collected using a grab sampler at three sites. Once retrieved, the sediments were homogenized and subsampled within 2 min for DNA analysis. Water samples were subsequently collected with 50-mL sterile centrifuge tubes. After collection, the samples were immediately stored in a refrigerator at 4°C. Within 1 day, the samples were transported cold (4°C) by a car to the Yantai Institute of Coastal Zone Research in Yantai. Characteristics of the sediments for all sampling sites were gravel-like and rich in brownish orange precipitates of iron (III) oxides.


Co-occurrence of Methanosarcina mazei and Geobacteraceae in an iron (III)-reducing enrichment culture.

Zheng S, Zhang H, Li Y, Zhang H, Wang O, Zhang J, Liu F - Front Microbiol (2015)

Location of the sampling points in the Jiehe (Jh) River watershed. The location of the sediment samples for this study is presented by solid circles (Zhang et al., 2014).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4562271&req=5

Figure 1: Location of the sampling points in the Jiehe (Jh) River watershed. The location of the sediment samples for this study is presented by solid circles (Zhang et al., 2014).
Mentions: Sediment samples were collected in July 2013 from the Jiehe River (37°05′N-37°33′N, 120°08′E-120°38′E), which is located in the northwest part of the Jiaodong peninsula, China (Figure 1). The geochemical characteristics of stream water were described previously (Zhang et al., 2014). Surface sediment layer (0–5 cm) and the pore water samples were collected using a grab sampler at three sites. Once retrieved, the sediments were homogenized and subsampled within 2 min for DNA analysis. Water samples were subsequently collected with 50-mL sterile centrifuge tubes. After collection, the samples were immediately stored in a refrigerator at 4°C. Within 1 day, the samples were transported cold (4°C) by a car to the Yantai Institute of Coastal Zone Research in Yantai. Characteristics of the sediments for all sampling sites were gravel-like and rich in brownish orange precipitates of iron (III) oxides.

Bottom Line: First, iron (III) reducers including Geobacteraceae were successfully enriched by 3-months successive culture on amorphous Fe(III) oxides as electron acceptor and acetate as electron donor.Remarkably, aggregates were successively formed in the enrichments after three transfers.The results revealed by RNA-based analysis demonstrate that the co-occurrence of Methanosarcina mazei and Geobacteraceae in an iron (III)-reducing enrichment culture.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences Yantai, China ; Key Laboratory of Coastal Biology and Biological Resources Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences Yantai, China.

ABSTRACT
Methanosaeta harundinacea and Methanosarcina barkeri, known as classic acetoclastic methanogens, are capable of directly accepting electrons from Geobacter metallireducens for the reduction of carbon dioxide to methane, having been revealed as direct interspecies electron transfer (DIET) in the laboratory co-cultures. However, whether their co-occurrences are ubiquitous in the iron (III)-reducing environments and the other species of acetoclastic methanogens such as Methanosarcina mazei are capable of DIET are still unknown. Instead of initiating the co-cultures with pure cultures, two-step cultivation was employed to selectively enrich iron (III)-reducing microorganisms in a coastal gold mining river, Jiehe River, with rich iron content in the sediments. First, iron (III) reducers including Geobacteraceae were successfully enriched by 3-months successive culture on amorphous Fe(III) oxides as electron acceptor and acetate as electron donor. High-throughput Illumina sequencing, terminal restriction fragment length polymorphism (T-RFLP) and clone library analysis based on 16S rRNA genes revealed that the enrichment cultures actively contained the bacteria belong to Geobacteraceae and Bacilli, exclusively dominated by the archaea belong to Methanosarcinaceae. Second, the enrichment cultures including methanogens and Geobacteraceae were transferred with ethanol as alternative electron donor. Remarkably, aggregates were successively formed in the enrichments after three transfers. The results revealed by RNA-based analysis demonstrate that the co-occurrence of Methanosarcina mazei and Geobacteraceae in an iron (III)-reducing enrichment culture. Furthermore, the aggregates, as close physical contact, formed in the enrichment culture, indicate that DIET could be a possible option for interspecies electron transfer in the aggregates.

No MeSH data available.