TY - JOUR
T1 - Identification of bacteria involved in the decomposition of lignocellulosic biomass treated with cow rumen fluid by metagenomic analysis
AU - Lee, Chol Gyu
AU - Baba, Yasunori
AU - Asano, Ryoki
AU - Fukuda, Yasuhiro
AU - Tada, Chika
AU - Nakai, Yutaka
N1 - Funding Information:
We thank Mr. Kazuya Sato and Ms. Rie Yamamoto of Field Science Center, Tohoku University, for their technical support during the collection of cow rumen contents. We would like to thank Editage for English language editing. This work was supported by the Next-generation Energies for Tohoku Recovery (NET) project.
Publisher Copyright:
© 2020 The Society for Biotechnology, Japan
PY - 2020/8
Y1 - 2020/8
N2 - We had developed a new pretreatment system using cow rumen fluid to improve the methane production from lignocellulosic substrates. However, the pretreatment conditions differ from the in-situ rumen environment, therefore different microbes may be involved in plant cell wall decomposition. In the current study, shotgun metagenomic analysis using MiSeq platform was performed to elucidate the bacteria which produce cellulase and hemicellulase in this pretreatment system. The rumen fluid which contained waste paper pieces (0.1% w/v) were incubated at 37°C during 120 h. The fluid samples were collected from the reactor at each time-point and analyzed for chemical properties. Rumen microbial DNA was extracted from 0-h and 60-h samples and subjected to shotgun-metagenomic analysis. After pretreatment, approximately half of cellulose and hemicellulose contents of the waste paper were decomposed and some volatile fatty acids were accumulated. Clostridia (e.g., Ruminococcus and Clostridium) were the predominant bacteria before and after 60-h pretreatment, and their relative abundance was increased during pretreatment. However, Prevotella and Fibrobacter, one of the most dominant bacteria in-situ rumen fluid, were observed less than 3% before incubation and they were decreased after pretreatment. Genes encoding cellulase and hemicellulase were mainly found in Ruminococcus, Clostridium, and Caldicellulosiruptor. Calicellulosiruptor, which had not been previously identified as the predominant genus in lignocellulose decomposition in in-situ rumen conditions, might be considered as the main fibrolytic bacterium in this system. Thus, this study demonstrated that the composition of fibrolytic bacteria in this system was greatly different from those in the in-situ rumen.
AB - We had developed a new pretreatment system using cow rumen fluid to improve the methane production from lignocellulosic substrates. However, the pretreatment conditions differ from the in-situ rumen environment, therefore different microbes may be involved in plant cell wall decomposition. In the current study, shotgun metagenomic analysis using MiSeq platform was performed to elucidate the bacteria which produce cellulase and hemicellulase in this pretreatment system. The rumen fluid which contained waste paper pieces (0.1% w/v) were incubated at 37°C during 120 h. The fluid samples were collected from the reactor at each time-point and analyzed for chemical properties. Rumen microbial DNA was extracted from 0-h and 60-h samples and subjected to shotgun-metagenomic analysis. After pretreatment, approximately half of cellulose and hemicellulose contents of the waste paper were decomposed and some volatile fatty acids were accumulated. Clostridia (e.g., Ruminococcus and Clostridium) were the predominant bacteria before and after 60-h pretreatment, and their relative abundance was increased during pretreatment. However, Prevotella and Fibrobacter, one of the most dominant bacteria in-situ rumen fluid, were observed less than 3% before incubation and they were decreased after pretreatment. Genes encoding cellulase and hemicellulase were mainly found in Ruminococcus, Clostridium, and Caldicellulosiruptor. Calicellulosiruptor, which had not been previously identified as the predominant genus in lignocellulose decomposition in in-situ rumen conditions, might be considered as the main fibrolytic bacterium in this system. Thus, this study demonstrated that the composition of fibrolytic bacteria in this system was greatly different from those in the in-situ rumen.
KW - Caldicellulosiruptor
KW - Clostridium
KW - Plant cell wall pretreatment
KW - Rumen fluid
KW - Ruminococcus
KW - β-Glucanase
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U2 - 10.1016/j.jbiosc.2020.03.010
DO - 10.1016/j.jbiosc.2020.03.010
M3 - Article
C2 - 32331776
AN - SCOPUS:85083518255
VL - 130
SP - 137
EP - 141
JO - Journal of Bioscience and Bioengineering
JF - Journal of Bioscience and Bioengineering
SN - 1389-1723
IS - 2
ER -