title: Fiber degradation potential of natural co-cultures of Neocallimastix frontalis and Methanobrevibacter ruminantium isolated from yaks (Bos grunniens) grazing on the Qinghai Tibetan Plateau.
abstract: Several natural anaerobic fungus-methanogen co-cultures have been isolated from rumen and feces source of herbivores with strong fiber degrading ability. In this study, we isolated 7 Neocallimastix with methanogen co-cultures from the rumen of yaks grazing on the Qinghai Tibetan Plateau. Based on morphological characteristics and internal transcribed spacer 1 sequences (ITS1), all the fungi were identified as Neocallimastix frontalis. The co-cultures were confirmed as the one fungus - one methanogen pattern by the PCR-denatured gradient gel electrophoresis (DGGE) assay. All the methanogens were identified as Methanobrevibacter ruminantium by 16s rRNA gene sequencing. We investigated the biodegrading capacity of the co-culture (N. frontalis + M. ruminantium) Yaktz1 on wheat straw, corn stalk and rice straw in a 7 days-incubation. The in vitro dry matter digestibility (IVDMD), acid detergent fiber digestibility (ADFD) and neural detergent fiber digestibility (NDFD) values of the substrates in the co-culture were significantly higher than those in the mono-culture N. frontalis Yaktz1. The co-culture exhibited high polysaccharide hydrolase (xylanase and FPase) and esterase activities. The xylanase in the co-culture reached the highest activity of 12500 mU/ml on wheat straw at the day 3 of the incubation. At the end of the incubation, 3.00 mmol-3.29 mmol/g dry matter of methane were produced by the co-culture. The co-culture also produced high level of acetate (40.00 mM-45.98 mM) as the end-product during the biodegradation. Interestingly, the N. frontalis Yaktz1 mono-culture produced large amount of lactate (8.27 mM-11.60 mM) and ethanol (163.11 mM-242.14 mM), many times more than those recorded in the previously reported anaerobic fungi. Our data suggests that the (N. frontalis + M. ruminantium) Yaktz1 co-culture and the N. frontalis Yaktz1 mono-culture both have great potentials for different industrial use.
authors.affiliation: Institute of Biological Research, Gansu Academy of Sciences, Lanzhou, 730000, PR China; School of Life Sciences, Lanzhou University, Lanzhou, 730000, PR China.
authors.forename: Ya-Qin
authors.initials: YQ
authors.lastname: Wei
authors.affiliation: School of Life Sciences, Lanzhou University, Lanzhou, 730000, PR China. Electronic address: long_rj2015@163.com.
authors.forename: Rui-Jun
authors.initials: RJ
authors.lastname: Long
authors.affiliation: Institute of Biological Research, Gansu Academy of Sciences, Lanzhou, 730000, PR China. Electronic address: yang_hui2016@163.com.
authors.forename: Hui
authors.initials: H
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, 100094, PR China. Electronic address: yang_hj2015@163.com.
authors.forename: Hong-Jian
authors.initials: HJ
authors.lastname: Yang
authors.affiliation: School of Life Sciences, Northewest Agricultural and Forestry University, Yangling, 712100, PR China. Electronic address: xhsmicro@gmail.com.
authors.forename: Xi-Hui
authors.initials: XH
authors.lastname: Shen
authors.affiliation: School of Chemical and Biological Engineering, Lanzhou Jiaotong University, Lanzhou, 730070, PR China.
authors.forename: Rui-Fang
authors.initials: RF
authors.lastname: Shi
authors.affiliation: Institute of Biological Research, Gansu Academy of Sciences, Lanzhou, 730000, PR China.
authors.forename: Zhi-Ye
authors.initials: ZY
authors.lastname: Wang
authors.affiliation: Institute of Biological Research, Gansu Academy of Sciences, Lanzhou, 730000, PR China.
authors.forename: Jun-Guo
authors.initials: JG
authors.lastname: Du
authors.affiliation: School of Life Sciences, Lanzhou University, Lanzhou, 730000, PR China.
authors.forename: Xiao-Jin
authors.initials: XJ
authors.lastname: Qi
authors.affiliation: State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, 100094, PR China.
authors.forename: Qian-Hong
authors.initials: QH
authors.lastname: Ye
mesh_terms: D019342:Acetic Acid / Q000378:metabolism; D000693:Anaerobiosis; D000818:Animals; D002417:Cattle; D018920:Coculture Techniques; D004043:Dietary Fiber / Q000378:metabolism*; D043364:Endo-1,4-beta Xylanases / Q000378:metabolism; D004950:Esterases / Q000378:metabolism; D000431:Ethanol / Q000378:metabolism; D000069196:Gastrointestinal Microbiome / Q000502:physiology*; D019344:Lactic Acid / Q000378:metabolism; D041581:Methanobrevibacter / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D020088:Neocallimastix / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D006109:Poaceae / Q000378:metabolism; D012336:RNA, Ribosomal, 16S / Q000235:genetics*; D012417:Rumen / Q000382:microbiology*; D017422:Sequence Analysis, DNA
chemical_list: D004043:Dietary Fiber; D012336:RNA, Ribosomal, 16S; D019344:Lactic Acid; D000431:Ethanol; D004950:Esterases; D043364:Endo-1,4-beta Xylanases; D019342:Acetic Acid
keywords: Methanobrevibacter ruminantium; Natural fungus-methanogen co-culture; Neocallimastix frontalis; Yaks