title: Pretreatment of lignocellulosic biomass by cattle rumen fluid for methane production: Bacterial flora and enzyme activity analysis.
abstract: We attempted to develop a pretreatment method for methane fermentation of lignocellulosic biomass using cattle rumen fluid, treated as slaughterhouse waste. When rapeseed (Brassica napus L.) was added to the methane fermentation after being solubilized with rumen fluid, 1.5 times more methane was produced compared with untreated rapeseed. Analysis of the bacterial flora during rumen fluid treatment using the MiSeq next-generation sequencer showed that the predominant phylum shifted from Bacteroidetes, composed of amylolytic Prevotella spp., to Firmicutes, composed of cellulolytic and xylanolytic Ruminococcus spp., in only 6 h. In total, 7 cellulolytic, 25 cello-oligosaccharolytic, and 11 xylanolytic bacteria were detected after investigating the most abundant sequences of detected taxa. The relative abundance of two Ruminococcus species (Ruminococcus albus and R. flavefaciens), known as cellulolytic, cello-oligosaccharolytic, and xylanolytic bacteria, increased with increasing cellulose and hemicellulose degradation rates, and, finally, comprised 48% of all operational taxonomic units. The chronological observation of enzyme activities showed that cellulolytic and xylanolytic activities increased 6 h later, and that oligosaccharolytic activity increased 24 h later. This study detected six bacteria that participate in the degradation of aromatics derived from lignin, which have rarely been reported in rumen fluid. The constitution of the detected bacteria suggests that the aromatics were converted into acetate via benzoate. The list of microbes that cover all lignocellulose-degrading candidates will provide fundamental knowledge for future studies focusing on rumen microbes.
authors.affiliation: Laboratory of Sustainable Animal Environmental Science, Graduate School of Agricultural Science, Tohoku University, Yomogida 232-3, Naruko-onsen, Osaki, Miyagi 989-6711, Japan; Research Fellow of the Japan Society for the Promotion of Science, Japan Society for the Promotion of Science, 5-3-1 Kojimachi, Chiyoda-ku, Tokyo 102-0083, Japan; Research Institute for Bioresources and Biotechnology, Ishikawa Prefectural University, Suematsu1-308, Nonoichi, Ishikawa 921-8836, Japan. Electronic address: ybaba@ishikawa-pu.ac.jp.
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Baba
authors.affiliation: Laboratory of Forest Ecology, Graduate School of Agricultural Science, Tohoku University, Yomogida 232-3, Naruko-onsen, Osaki, Miyagi 989-6711, Japan.
authors.forename: Yu
authors.initials: Y
authors.lastname: Matsuki
authors.affiliation: Laboratory of Sustainable Animal Environmental Science, Graduate School of Agricultural Science, Tohoku University, Yomogida 232-3, Naruko-onsen, Osaki, Miyagi 989-6711, Japan.
authors.forename: Yumi
authors.initials: Y
authors.lastname: Mori
authors.affiliation: Laboratory of Forest Ecology, Graduate School of Agricultural Science, Tohoku University, Yomogida 232-3, Naruko-onsen, Osaki, Miyagi 989-6711, Japan.
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Suyama
authors.affiliation: Laboratory of Sustainable Animal Environmental Science, Graduate School of Agricultural Science, Tohoku University, Yomogida 232-3, Naruko-onsen, Osaki, Miyagi 989-6711, Japan.
authors.forename: Chika
authors.initials: C
authors.lastname: Tada
authors.affiliation: Laboratory of Sustainable Animal Environmental Science, Graduate School of Agricultural Science, Tohoku University, Yomogida 232-3, Naruko-onsen, Osaki, Miyagi 989-6711, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Fukuda
authors.affiliation: Laboratory of Environmental Crop Science, Graduate School of Agricultural Science, Tohoku University, Yomogida 232-3, Naruko-onsen, Osaki, Miyagi 989-6711, Japan.
authors.forename: Masanori
authors.initials: M
authors.lastname: Saito
authors.affiliation: Laboratory of Sustainable Animal Environmental Science, Graduate School of Agricultural Science, Tohoku University, Yomogida 232-3, Naruko-onsen, Osaki, Miyagi 989-6711, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Nakai
mesh_terms: D000003:Abattoirs; D000818:Animals; D041963:Bacteroidetes / Q000302:isolation & purification / Q000378:metabolism; D018533:Biomass; D001826:Body Fluids / Q000201:enzymology* / Q000382:microbiology*; D029688:Brassica napus / Q000737:chemistry; D002417:Cattle; D002482:Cellulose / Q000378:metabolism; D005285:Fermentation; D008031:Lignin / Q000378:metabolism*; D008697:Methane / Q000096:biosynthesis*; D011134:Polysaccharides / Q000378:metabolism; D012417:Rumen / Q000201:enzymology* / Q000382:microbiology*; D045857:Ruminococcus / Q000302:isolation & purification / Q000378:metabolism; D018505:Waste Management
chemical_list: D011134:Polysaccharides; C036909:lignocellulose; C007916:hemicellulose; D002482:Cellulose; D008031:Lignin; D008697:Methane
keywords: Enzyme activity; Lignocellulosic biomass; Methane fermentation; Next-generation sequencer; Pretreatment; Rumen bacterial flora