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Dynamic variation of the microbial community structure during the long-time mono-fermentation of maize and sugar beet silage.

Klang J, Theuerl S, Szewzyk U, Huth M, Tölle R, Klocke M - Microb Biotechnol (2015)

Bottom Line: Based on the high amount of complex compounds, the anaerobic conversion rate of maize silage was slightly lower compared with the sugar beet silage.It was further shown that species of the genus Methanosaeta are highly sensitive against sudden stress situations such as a strong decrease in the ammonium nitrogen (NH₄(+)-N) concentration or a drop of the pH value.However, the overall biomass conversion of both feedstocks proceeded efficiently as a steady state between acid production and consumption was recorded, which further resulted in an equal biogas yield.

View Article: PubMed Central - PubMed

Affiliation: Department Bioengineering, Leibniz Institute for Agricultural Engineering, Max Eyth Allee 100, Potsdam, 14469, Germany.

No MeSH data available.


Correlation between the abundance of TRF-428bp (related to Methanoculleus) and TRF-108bp (related to Methanosaeta) in (A) the maize reactors and (B) the sugar beet reactors. Only samples indicated by a full black dot were considered for correlation. R2 is the correlation coefficient.
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fig05: Correlation between the abundance of TRF-428bp (related to Methanoculleus) and TRF-108bp (related to Methanosaeta) in (A) the maize reactors and (B) the sugar beet reactors. Only samples indicated by a full black dot were considered for correlation. R2 is the correlation coefficient.

Mentions: From day 33 to day 57, the calculated dissimilarity values still showed high structural changes between the communities. The changes decreased evidently over time until the community shift reached 1% in the maize system and 5% in the sugar beet system between day 93 and 141, meaning that the archeal community structure became more and more similar over time. During the start-up phase, which was accompanied by a decrease in the NH4+-N level (Fig. 2), the genus Methanosaeta, represented by the TRF-108bp, became predominant with 86% of the total archaeal community in the maize reactors, whereas the abundance of the genus Methanoculleus decreased. This can be explained as the inhibitory effect of high NH4+-N concentration on the acetoclastic methanogenes pathway (e.g. Schnürer and Nordberg, 2008; Fotidis et al., 2014) was successively reduced over time. Interestingly and first described in this study, a further decrease of the NH4+-N concentration promoted the re-occurrence of the genus Methanoculleus (between day 175 and 267, Fig. 4A). After day 267 until the end of the experimental phase, the NH4+-N concentration in the maize reactors was kept rather constant at around 450 mg kgFM−1. Consequently, the Methanoculleus-related TRF-428bp completely disappeared, and finally, the archaeal community of the maize reactor was clearly dominated by the obligate acetoclastic genus Methanosaeta (TRF-108bp, 87%). Thus, the results revealed an antagonistic behaviour between the genera Methanosaeta (symbolizes by TRF-108bp) and Methanoculleus (TRF-428bp), in the maize reactor systems (Fig. 5A). Apparently, species of the genus Methanosaeta are highly sensitive against sudden stress situations, whereby Methanoculleus seems to be more robust. Moreover, it can be supposed that the decreasing and especially the low NH4+-N concentration influence not only the archaeal community composition, but also the bacterial one. This in turn may lead to the production of metabolites, which favour the presence of Methanoculleus. For example, between day 175 and 267, members from family Anaerolineacea (phylum Cloriflexi) became abundant (Fig. 3A, Table 2). It is known that the growth for example of the genus Longilinea is enhanced in co-culture with hydrogenotrophic methanogens (Yamada et al., 2007). Nevertheless, after keeping the NH4+-N concentration rather constant to avoid a process failure, the genus Methanosaeta is dominating the archaeal community again.


Dynamic variation of the microbial community structure during the long-time mono-fermentation of maize and sugar beet silage.

Klang J, Theuerl S, Szewzyk U, Huth M, Tölle R, Klocke M - Microb Biotechnol (2015)

Correlation between the abundance of TRF-428bp (related to Methanoculleus) and TRF-108bp (related to Methanosaeta) in (A) the maize reactors and (B) the sugar beet reactors. Only samples indicated by a full black dot were considered for correlation. R2 is the correlation coefficient.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4554465&req=5

fig05: Correlation between the abundance of TRF-428bp (related to Methanoculleus) and TRF-108bp (related to Methanosaeta) in (A) the maize reactors and (B) the sugar beet reactors. Only samples indicated by a full black dot were considered for correlation. R2 is the correlation coefficient.
Mentions: From day 33 to day 57, the calculated dissimilarity values still showed high structural changes between the communities. The changes decreased evidently over time until the community shift reached 1% in the maize system and 5% in the sugar beet system between day 93 and 141, meaning that the archeal community structure became more and more similar over time. During the start-up phase, which was accompanied by a decrease in the NH4+-N level (Fig. 2), the genus Methanosaeta, represented by the TRF-108bp, became predominant with 86% of the total archaeal community in the maize reactors, whereas the abundance of the genus Methanoculleus decreased. This can be explained as the inhibitory effect of high NH4+-N concentration on the acetoclastic methanogenes pathway (e.g. Schnürer and Nordberg, 2008; Fotidis et al., 2014) was successively reduced over time. Interestingly and first described in this study, a further decrease of the NH4+-N concentration promoted the re-occurrence of the genus Methanoculleus (between day 175 and 267, Fig. 4A). After day 267 until the end of the experimental phase, the NH4+-N concentration in the maize reactors was kept rather constant at around 450 mg kgFM−1. Consequently, the Methanoculleus-related TRF-428bp completely disappeared, and finally, the archaeal community of the maize reactor was clearly dominated by the obligate acetoclastic genus Methanosaeta (TRF-108bp, 87%). Thus, the results revealed an antagonistic behaviour between the genera Methanosaeta (symbolizes by TRF-108bp) and Methanoculleus (TRF-428bp), in the maize reactor systems (Fig. 5A). Apparently, species of the genus Methanosaeta are highly sensitive against sudden stress situations, whereby Methanoculleus seems to be more robust. Moreover, it can be supposed that the decreasing and especially the low NH4+-N concentration influence not only the archaeal community composition, but also the bacterial one. This in turn may lead to the production of metabolites, which favour the presence of Methanoculleus. For example, between day 175 and 267, members from family Anaerolineacea (phylum Cloriflexi) became abundant (Fig. 3A, Table 2). It is known that the growth for example of the genus Longilinea is enhanced in co-culture with hydrogenotrophic methanogens (Yamada et al., 2007). Nevertheless, after keeping the NH4+-N concentration rather constant to avoid a process failure, the genus Methanosaeta is dominating the archaeal community again.

Bottom Line: Based on the high amount of complex compounds, the anaerobic conversion rate of maize silage was slightly lower compared with the sugar beet silage.It was further shown that species of the genus Methanosaeta are highly sensitive against sudden stress situations such as a strong decrease in the ammonium nitrogen (NH₄(+)-N) concentration or a drop of the pH value.However, the overall biomass conversion of both feedstocks proceeded efficiently as a steady state between acid production and consumption was recorded, which further resulted in an equal biogas yield.

View Article: PubMed Central - PubMed

Affiliation: Department Bioengineering, Leibniz Institute for Agricultural Engineering, Max Eyth Allee 100, Potsdam, 14469, Germany.

No MeSH data available.