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Froidurot A, Jacotot E, Julliand S, Grimm P, Julliand V. Fibrobacter sp. HC4, a newly isolated strain, demonstrates a high cellulolytic activity as revealed by enzymatic measurements and in vitro assay. Appl Environ Microbiol 2024; 90:e0051424. [PMID: 39082812 PMCID: PMC11337828 DOI: 10.1128/aem.00514-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Accepted: 06/17/2024] [Indexed: 08/22/2024] Open
Abstract
Despite their low quantity and abundance, the cellulolytic bacteria that inhabit the equine large intestine are vital to their host, as they enable the crucial use of forage-based diets. Fibrobacter succinogenes is one of the most important intestinal cellulolytic bacteria. In this study, Fibrobacter sp. HC4, one cellulolytic strain newly isolated from the horse cecum, was characterized for its ability to utilize plant cell wall fibers. Fibrobacter sp. HC4 consumed only cellulose, cellobiose, and glucose and produced succinate and acetate in equal amounts. Among genes coding for CAZymes, 26% of the detected glycoside hydrolases (GHs) were involved in cellulolysis. These cellulases belong to the GH5, GH8, GH9, GH44, GH45, and GH51 families. Both carboxymethyl cellulase and xylanase activities of Fibrobacter sp. HC4 were detected using the Congo red method and were higher than those of F. succinogenes S85, the type strain. The in vitro addition of Fibrobacter sp. HC4 to a fecal microbial ecosystem of horses with large intestinal acidosis significantly enhanced fibrolytic activity as measured by the increase in gas and volatile fatty acids production during the first 48 h. According to this, the pH decreased and the disappearance of dry matter increased at a faster rate with Fibrobacter sp. HC4. Our data suggest a high specialization of the new strain in cellulose degradation. Such a strain could be of interest for future exploitation of its probiotic potential, which needs to be further determined by in vivo studies.IMPORTANCECellulose is the most abundant of plant cell wall fiber and can only be degraded by the large intestine microbiota, resulting in the production of volatile fatty acids that are essential for the host nutrition and health. Consequently, cellulolytic bacteria are of major importance to herbivores. However, these bacteria are challenged by various factors, such as high starch diets, which acidify the ecosystem and reduce their numbers and activity. This can lead to an imbalance in the gut microbiota and digestive problems such as colic, a major cause of mortality in horses. In this work, we characterized a newly isolated cellulolytic strain, Fibrobacter sp. HC4, from the equine intestinal microbiota. Due to its high cellulolytic capacity, reintroduction of this strain into an equine fecal ecosystem stimulates hay fermentation in vitro. Isolating and describing cellulolytic bacteria is a prerequisite for using them as probiotics to restore intestinal balance.
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Affiliation(s)
- Alicia Froidurot
- Univ. Bourgogne Franche–Comté, L’Institut Agro Dijon, PAM UMR A 02.102, Dijon, France
| | - Emmanuel Jacotot
- Univ. Bourgogne Franche–Comté, L’Institut Agro Dijon, PAM UMR A 02.102, Dijon, France
| | | | | | - Véronique Julliand
- Univ. Bourgogne Franche–Comté, L’Institut Agro Dijon, PAM UMR A 02.102, Dijon, France
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Jiang Q, Sherlock DN, Elolimy AA, Yoon I, Loor JJ. Feeding a Saccharomyces cerevisiae fermentation product during a gut barrier challenge in lactating Holstein cows impacts the ruminal microbiota and metabolome. J Dairy Sci 2024; 107:4476-4494. [PMID: 38369118 DOI: 10.3168/jds.2023-24147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Accepted: 01/11/2024] [Indexed: 02/20/2024]
Abstract
Through its influence on the gut microbiota, the feeding of Saccharomyces cerevisiae fermentation products (SCFP) has been a successful strategy to enhance the health of dairy cows during periods of physiological stresses. Although production and metabolic outcomes from feeding SCFP are well-known, its combined impacts on the ruminal microbiota and metabolome during gut barrier challenges remain unclear. To address this gap in knowledge, multiparous Holstein cows (97.1 ± 7.6 DIM [SD]; n = 8/group) fed a control diet (CON) or CON plus 19 g/d SCFP for 9 wk were subjected to a feed restriction (FR) challenge for 5 d, during which they were fed 40% of their ad libitum intake from the 7 d before FR. The DNA extracted from ruminal fluid was subjected to PacBio full-length 16S rRNA gene sequencing, real-time PCR of 12 major ruminal bacteria, and metabolomics analysis of up to 189 metabolites via GC/MS. High-quality amplicon sequence analyses were performed with the TADA (Targeted Amplicon Diversity Analysis), MicrobiomeAnalyst, PICRUSt2, and STAMP software packages, and metabolomics data were analyzed via MetaboAnalyst 5.0. Ruminal fluid metabolites from the SCFP group exhibited a greater α-diversity Chao 1 (P = 0.03) and Shannon indices (P = 0.05), and the partial least squares discriminant analysis clearly discriminated metabolite profiles between dietary groups. The abundance of CPla_4_termite_group, Candidatus Saccharimonas, Oribacterium, and Pirellula genus in cows fed SCFP was greater. In the SCFP group, concentrations of ethanolamine, 2-amino-4,6-dihydroxypyrimidine, glyoxylic acid, serine, threonine, cytosine, stearic acid, and pyrrole-2-carboxylic acid were greater in ruminal fluid. Both Fretibacterium and Succinivibrio abundances were positively correlated with metabolites across various biological processes: gamma-aminobutyric acid, galactose, butane-2,3-diol, fructose, 5-amino pentanoic acid, β-aminoisobutyric acid, ornithine, malonic acid, 3-hydroxy-3-methylbutyric acid, hexanoic acid, heptanoic acid, cadaverine, glycolic acid, β-alanine, 2-hydroxybutyric acid, methyl alanine, and alanine. In the SCFP group, compared with CON, the mean proportion of 14 predicted pathways based on metabolomics data was greater, whereas 10 predicted pathways were lower. Integrating metabolites and upregulated predicted enzymes (NADP+-dependent glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, serine: glyoxylate aminotransferase, and d-glycerate 3-kinase) indicated that the pentose phosphate pathway and photorespiration pathway were most upregulated by SCFP. Overall, SCFP during FR led to alterations in ruminal microbiota composition and key metabolic pathways. Among those, we identified a shift from the tricarboxylic acid cycle to the glyoxylate cycle, and nitrogenous base production was enhanced.
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Affiliation(s)
- Qianming Jiang
- Department of Animal Sciences, University of Illinois, Urbana, IL 61801
| | | | - Ahmed A Elolimy
- Department of Animal Sciences, University of Illinois, Urbana, IL 61801; Livestock Production and Management, Department of Integrated Agriculture, College of Agriculture and Veterinary Medicine, United Arab Emirates University, Al Ain 1551, United Arab Emirates
| | | | - Juan J Loor
- Department of Animal Sciences, University of Illinois, Urbana, IL 61801.
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Yang Z, Bao L, Song W, Zhao X, Liang H, Yu M, Qu M. Nicotinic acid changes rumen fermentation and apparent nutrient digestibility by regulating rumen microbiota in Xiangzhong black cattle. Anim Biosci 2024; 37:240-252. [PMID: 37905319 PMCID: PMC10766483 DOI: 10.5713/ab.23.0149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2023] [Revised: 06/25/2023] [Accepted: 09/06/2023] [Indexed: 11/02/2023] Open
Abstract
OBJECTIVE The aim of this study was to investigate the impact of dietary nicotinic acid (NA) on apparent nutrient digestibility, rumen fermentation, and rumen microbiota in uncastrated Xiangzhong black cattle. METHODS Twenty-one uncastrated Xiangzhong black cattle (385.08±15.20 kg) aged 1.5 years were randomly assigned to the control group (CL, 0 mg/kg NA in concentrate diet), NA1 group (800 mg/kg NA in concentrate diet) and NA2 group (1,200 mg/kg NA in concentrate diet). All animals were fed a 60% concentrate diet and 40% dried rice straw for a 120-day feeding experiment. RESULTS Supplemental NA not only enhanced the apparent nutrient digestibility of acid detergent fiber (p<0.01), but also elevated the rumen acetate and total volatile fatty acid concentrations (p<0.05). 16S rRNA gene sequencing analysis of rumen microbiota revealed that dietary NA changed the diversity of rumen microbiota (p<0.05) and the abundance of bacterial taxa in the rumen. The relative abundances of eight Erysipelotrichales taxa, five Ruminococcaceae taxa, and five Sphaerochaetales taxa were decreased by dietary NA (p< 0.05). However, the relative abundances of two taxa belonging to Roseburia faecis were increased by supplemental 800 mg/kg NA, and the abundances of seven Prevotella taxa, three Paraprevotellaceae taxa, three Bifidobacteriaceae taxa, and two operational taxonomic units annotated to Fibrobacter succinogenes were increased by 1,200 mg/kg NA in diets. Furthermore, the correlation analysis found significant correlations between the concentrations of volatile fatty acids in the rumen and the abundances of bacterial taxa, especially Prevotella. CONCLUSION The results from this study suggest that dietary NA plays an important role in regulating apparent digestibility of acid detergent fiber, acetate, total volatile fatty acid concentrations, and the composition of rumen microbiota.
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Affiliation(s)
- Zhuqing Yang
- College of Animal Science and Technology, Jiangxi Agricultural University, Nanchang 330045,
China
| | - Linbin Bao
- Animal Husbandry and Veterinary Bureau of Guangchang County, Fuzhou, Jiangxi, 344900,
China
| | - Wanming Song
- College of Animal Science and Technology, Jiangxi Agricultural University, Nanchang 330045,
China
| | - Xianghui Zhao
- Jiangxi Provincial Key Laboratory for Animal Nutrition/Engineering Research Center of Feed Development, Jiangxi Agricultural University, Nanchang, 330045,
China
| | - Huan Liang
- Jiangxi Provincial Key Laboratory for Animal Nutrition/Engineering Research Center of Feed Development, Jiangxi Agricultural University, Nanchang, 330045,
China
| | - Mingjin Yu
- College of Animal Science and Technology, Jiangxi Agricultural University, Nanchang 330045,
China
| | - Mingren Qu
- Jiangxi Provincial Key Laboratory for Animal Nutrition/Engineering Research Center of Feed Development, Jiangxi Agricultural University, Nanchang, 330045,
China
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Heom KA, Wangsanuwat C, Butkovich LV, Tam SC, Rowe AR, O'Malley MA, Dey SS. Targeted rRNA depletion enables efficient mRNA sequencing in diverse bacterial species and complex co-cultures. mSystems 2023; 8:e0028123. [PMID: 37855606 PMCID: PMC10734481 DOI: 10.1128/msystems.00281-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Accepted: 09/12/2023] [Indexed: 10/20/2023] Open
Abstract
IMPORTANCE Microbes present one of the most diverse sources of biochemistry in nature, and mRNA sequencing provides a comprehensive view of this biological activity by quantitatively measuring microbial transcriptomes. However, efficient mRNA capture for sequencing presents significant challenges in prokaryotes as mRNAs are not poly-adenylated and typically make up less than 5% of total RNA compared with rRNAs that exceed 80%. Recently developed methods for sequencing bacterial mRNA typically rely on depleting rRNA by tiling large probe sets against rRNAs; however, such approaches are expensive, time-consuming, and challenging to scale to varied bacterial species and complex microbial communities. Therefore, we developed EMBR-seq+, a method that requires fewer than 10 short oligonucleotides per rRNA to achieve up to 99% rRNA depletion in diverse bacterial species. Finally, EMBR-seq+ resulted in a deeper view of the transcriptome, enabling systematic quantification of how microbial interactions result in altering the transcriptional state of bacteria within co-cultures.
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Affiliation(s)
- Kellie A. Heom
- Department of Chemical Engineering, University of California Santa Barbara, Santa Barbara, California, USA
- Biological Engineering Program, University of California Santa Barbara, Santa Barbara, California, USA
| | - Chatarin Wangsanuwat
- Department of Chemical Engineering, University of California Santa Barbara, Santa Barbara, California, USA
- Biological Engineering Program, University of California Santa Barbara, Santa Barbara, California, USA
| | - Lazarina V. Butkovich
- Department of Chemical Engineering, University of California Santa Barbara, Santa Barbara, California, USA
| | - Scott C. Tam
- Department of Chemical Engineering, University of California Santa Barbara, Santa Barbara, California, USA
| | - Annette R. Rowe
- Biological Sciences, University of Cincinnati, Cincinnati, Ohio, USA
| | - Michelle A. O'Malley
- Department of Chemical Engineering, University of California Santa Barbara, Santa Barbara, California, USA
- Biological Engineering Program, University of California Santa Barbara, Santa Barbara, California, USA
| | - Siddharth S. Dey
- Department of Chemical Engineering, University of California Santa Barbara, Santa Barbara, California, USA
- Biological Engineering Program, University of California Santa Barbara, Santa Barbara, California, USA
- Neuroscience Research Institute, University of California Santa Barbara, Santa Barbara, California, USA
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Mitchell KE, Kienzle SL, Lee C, Socha MT, Kleinschmit DH, Firkins JL. Supplementing branched-chain volatile fatty acids in dual-flow cultures varying in dietary forage and corn oil concentrations. II: Biohydrogenation and incorporation into bacterial lipids. J Dairy Sci 2023; 106:7548-7565. [PMID: 37532628 DOI: 10.3168/jds.2022-23192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 03/17/2023] [Indexed: 08/04/2023]
Abstract
To maintain membrane homeostasis, ruminal bacteria synthesize branched-chain fatty acids (BCFA) or their derivatives (vinyl ethers) that are recovered during methylation procedures as branched-chain aldehydes (BCALD). Many strains of cellulolytic bacteria require 1 or more branched-chain volatile fatty acid (BCVFA). Therefore, the objective of this study was to investigate BCVFA incorporation into bacterial lipids under different dietary conditions. The study was an incomplete block design with 8 continuous culture fermenters used in 4 periods with treatments (n = 4) arranged as a 2 × 2 × 2 factorial. The factors were high (HF) or low forage (LF, 67 or 33% forage, 33:67 alfalfa:orchardgrass), without or with supplemental corn oil (CO; 3% dry matter, 1.5% linoleic fatty acid), and without or with 2.15 mmol/d (5 mg/d 13C each of isovalerate, isobutyrate, and 2-methylbutyrate). After methylation of bacterial pellets collected from each fermenter's effluent, fatty acids and fatty aldehydes were separated before analysis by gas chromatography and isotope ratio mass spectrometry. Supplementation of BCVFA did not influence biohydrogenation extent. Label was only recovered in branched-chain lipids. Lower forage inclusion decreased BCFA in bacterial fatty acid profile from 9.45% with HF to 7.06% with LF and decreased BCALD in bacterial aldehyde profile from 55.4% with HF to 51.4% with LF. Supplemental CO tended to decrease iso even-chain BCFA and decreased iso even-chain BCALD in their bacterial lipid profiles. The main 18:1 isomer was cis-9 18:1, which increased (P < 0.01) by 25% from CO (data not shown). Dose recovery in bacterial lipids was 43.3% lower with LF than HF. Supplemental CO decreased recovery in the HF diet but increased recovery with LF (diet × CO interaction). Recovery from anteiso odd-chain BCFA and BCALD was the greatest; therefore, 2-methylbutyrate was the BCVFA primer most used for branched-chain lipid synthesis. Recovery in iso odd-chain fatty acids (isovalerate as primer) was greater than label recovery in iso even-chain fatty acids (isobutyrate as primer). Fatty aldehydes were less than 6% of total bacterial lipids, but 26.0% of 13C recovered in lipids were recovered in BCALD because greater than 50% of aldehydes were branched-chain. Because BCFA and BCALD are important in the function and growth of bacteria, especially cellulolytics, BCVFA supplementation can support the rumen microbial consortium, increasing fiber degradation and efficiency of microbial protein synthesis.
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Affiliation(s)
| | | | - C Lee
- Department of Animal Sciences, The Ohio State University, Wooster, OH 44691
| | - M T Socha
- Zinpro Corporation, Eden Prairie, MN 55344
| | | | - J L Firkins
- Department of Animal Sciences, The Ohio State University, Columbus, OH 43035
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Gharechahi J, Vahidi MF, Sharifi G, Ariaeenejad S, Ding XZ, Han JL, Salekdeh GH. Lignocellulose degradation by rumen bacterial communities: New insights from metagenome analyses. ENVIRONMENTAL RESEARCH 2023; 229:115925. [PMID: 37086884 DOI: 10.1016/j.envres.2023.115925] [Citation(s) in RCA: 23] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 03/26/2023] [Accepted: 04/15/2023] [Indexed: 05/03/2023]
Abstract
Ruminant animals house a dense and diverse community of microorganisms in their rumen, an enlarged compartment in their stomach, which provides a supportive environment for the storage and microbial fermentation of ingested feeds dominated by plant materials. The rumen microbiota has acquired diverse and functionally overlapped enzymes for the degradation of plant cell wall polysaccharides. In rumen Bacteroidetes, enzymes involved in degradation are clustered into polysaccharide utilization loci to facilitate coordinated expression when target polysaccharides are available. Firmicutes use free enzymes and cellulosomes to degrade the polysaccharides. Fibrobacters either aggregate lignocellulose-degrading enzymes on their cell surface or release them into the extracellular medium in membrane vesicles, a mechanism that has proven extremely effective in the breakdown of recalcitrant cellulose. Based on current metagenomic analyses, rumen Bacteroidetes and Firmicutes are categorized as generalist microbes that can degrade a wide range of polysaccharides, while other members adapted toward specific polysaccharides. Particularly, there is ample evidence that Verrucomicrobia and Spirochaetes have evolved enzyme systems for the breakdown of complex polysaccharides such as xyloglucans, peptidoglycans, and pectin. It is concluded that diversity in degradation mechanisms is required to ensure that every component in feeds is efficiently degraded, which is key to harvesting maximum energy by host animals.
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Affiliation(s)
- Javad Gharechahi
- Human Genetics Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Mohammad Farhad Vahidi
- Animal Science Research Department, Qom Agricultural and Natural Resources Research and Education Center, Agricultural Research, Education and Extension Organization (AREEO), Qom, Iran
| | - Golandam Sharifi
- Department of Basic Sciences, Encyclopedia Research Center, Institute for Humanities and Cultural Studies, Tehran, Iran
| | - Shohreh Ariaeenejad
- Department of Systems Biology, Agricultural Biotechnology Research Institute of Iran, Agricultural Research, Education, And Extension Organization, Karaj, Iran
| | - Xue-Zhi Ding
- Key Laboratory of Yak Breeding Engineering, Lanzhou Institute of Husbandry and Pharmaceutical Sciences, Chinese Academy of Agricultural Sciences (CAAS), Lanzhou, 730050, China
| | - Jian-Lin Han
- Livestock Genetics Program, International Livestock Research, Institute (ILRI), 00100, Nairobi, Kenya; CAAS-ILRI Joint Laboratory on Livestock and Forage Genetic Resources, Institute of Animal Science, Chinese Academy of Agricultural Sciences (CAAS), Beijing, 100193, China.
| | - Ghasem Hosseini Salekdeh
- Department of Systems Biology, Agricultural Biotechnology Research Institute of Iran, Agricultural Research, Education, And Extension Organization, Karaj, Iran; School of Natural Sciences, Macquarie University, North Ryde, NSW, Australia.
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García-Maldonado JQ, Latisnere-Barragán H, Escobar-Zepeda A, Cadena S, Ramírez-Arenas PJ, Vázquez-Juárez R, Rojas-Contreras M, López-Cortés A. Revisiting Microbial Diversity in Hypersaline Microbial Mats from Guerrero Negro for a Better Understanding of Methanogenic Archaeal Communities. Microorganisms 2023; 11:microorganisms11030812. [PMID: 36985385 PMCID: PMC10059902 DOI: 10.3390/microorganisms11030812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 02/21/2023] [Accepted: 02/23/2023] [Indexed: 03/30/2023] Open
Abstract
Knowledge regarding the diversity of methanogenic archaeal communities in hypersaline environments is limited because of the lack of efficient cultivation efforts as well as their low abundance and metabolic activities. In this study, we explored the microbial communities in hypersaline microbial mats. Bioinformatic analyses showed significant differences among the archaeal community structures for each studied site. Taxonomic assignment based on 16S rRNA and methyl coenzyme-M reductase (mcrA) gene sequences, as well as metagenomic analysis, corroborated the presence of Methanosarcinales. Furthermore, this study also provided evidence for the presence of Methanobacteriales, Methanomicrobiales, Methanomassiliicoccales, Candidatus Methanofastidiosales, Methanocellales, Methanococcales and Methanopyrales, although some of these were found in extremely low relative abundances. Several mcrA environmental sequences were significantly different from those previously reported and did not match with any known methanogenic archaea, suggesting the presence of specific environmental clusters of methanogenic archaea in Guerrero Negro. Based on functional inference and the detection of specific genes in the metagenome, we hypothesised that all four methanogenic pathways were able to occur in these environments. This study allowed the detection of extremely low-abundance methanogenic archaea, which were highly diverse and with unknown physiology, evidencing the presence of all methanogenic metabolic pathways rather than the sheer existence of exclusively methylotrophic methanogenic archaea in hypersaline environments.
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Affiliation(s)
- José Q García-Maldonado
- Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Unidad Mérida, Mérida 97310, Yucatán, Mexico
| | - Hever Latisnere-Barragán
- Centro de Investigaciones Biológicas del Noroeste (CIBNOR), La Paz 23205, Baja California Sur, Mexico
| | | | - Santiago Cadena
- Centro de Investigaciones Químicas, Universidad Autónoma del Estado de Morelos, Cuernavaca 62209, Morelos, Mexico
| | - Patricia J Ramírez-Arenas
- Centro de Investigaciones Biológicas del Noroeste (CIBNOR), La Paz 23205, Baja California Sur, Mexico
| | - Ricardo Vázquez-Juárez
- Centro de Investigaciones Biológicas del Noroeste (CIBNOR), La Paz 23205, Baja California Sur, Mexico
| | - Maurilia Rojas-Contreras
- Departamento de Agronomía, Universidad Autónoma de Baja California Sur, La Paz 23080, Baja California Sur, Mexico
| | - Alejandro López-Cortés
- Centro de Investigaciones Biológicas del Noroeste (CIBNOR), La Paz 23205, Baja California Sur, Mexico
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Sechovcová H, Rudl Kulhavá L, Fliegerová K, Killer J, Kopečný J. Advantages of label free method in comparison with 2DE proteomic analysis of Butyrivibrio fibrisolvens 3071 grown on different carbon sources. ITALIAN JOURNAL OF ANIMAL SCIENCE 2022. [DOI: 10.1080/1828051x.2022.2129477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Hana Sechovcová
- Institute of Animal Physiology and Genetics, CAS, Laboratory of Anaerobic Microbiology, Prague, Czech Republic
- Czech University of Life Sciences, Faculty of Agrobiology, Food and Natural Resources, Department of Microbiology, Nutrition and Dietetics, Prague, Czech Republic
| | | | - Kateřina Fliegerová
- Institute of Animal Physiology and Genetics, CAS, Laboratory of Anaerobic Microbiology, Prague, Czech Republic
| | - Jiří Killer
- Institute of Animal Physiology and Genetics, CAS, Laboratory of Anaerobic Microbiology, Prague, Czech Republic
- Czech University of Life Sciences, Faculty of Agrobiology, Food and Natural Resources, Department of Microbiology, Nutrition and Dietetics, Prague, Czech Republic
| | - Jan Kopečný
- Institute of Animal Physiology and Genetics, CAS, Laboratory of Anaerobic Microbiology, Prague, Czech Republic
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Weimer PJ. Degradation of Cellulose and Hemicellulose by Ruminal Microorganisms. Microorganisms 2022; 10:2345. [PMID: 36557598 PMCID: PMC9785684 DOI: 10.3390/microorganisms10122345] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2022] [Revised: 11/19/2022] [Accepted: 11/26/2022] [Indexed: 11/29/2022] Open
Abstract
As major structural components of plant cell walls, cellulose and hemicellulose are degraded and fermented by anaerobic microbes in the rumen to produce volatile fatty acids, the main nutrient source for the host. Cellulose degradation is carried out primarily by specialist bacteria, with additional contributions from protists and fungi, via a variety of mechanisms. Hemicelluloses are hydrolyzed by cellulolytic bacteria and by generalist, non-cellulolytic microbes, largely via extracellular enzymes. Cellulose hydrolysis follows first-order kinetics and its rate is limited by available substrate surface area. Nevertheless, its rate is at least an order of magnitude more rapid than in anaerobic digesters, due to near-obligatory adherence of microbial cells to the cellulose surface, and a lack of downstream inhibitory effects; in the host animal, fiber degradation rate is also enhanced by the unique process of rumination. Cellulolytic and hemicellulolytic microbes exhibit intense competition and amensalism, but they also display mutualistic interactions with microbes at other trophic levels. Collectively, the fiber-degrading community of the rumen displays functional redundancy, partial niche overlap, and convergence of catabolic pathways that all contribute to stability of the ruminal fermentation. The superior hydrolytic and fermentative capabilities of ruminal fiber degraders make them promising candidates for several fermentation technologies.
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Affiliation(s)
- Paul J Weimer
- Department of Bacteriology, University of Wisconsin, Madison, WI 53706, USA
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10
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Abstract
The utilization of dietary cellulose by resident bacteria in the large intestine of mammals, both herbivores and omnivores (including humans), has been a subject of interest since the nineteenth century. Cellulolytic bacteria are key participants in this breakdown process of cellulose, which is otherwise indigestible by the host. They critically contribute to host nutrition and health through the production of short-chain fatty acids, in addition to maintaining the balance of intestinal microbiota. Despite this key role, cellulolytic bacteria have not been well studied. In this review, we first retrace the history of the discovery of cellulolytic bacteria in the large intestine. We then focus on the current knowledge of cellulolytic bacteria isolated from the large intestine of various animal species and humans and discuss the methods used for isolating these bacteria. Moreover, we summarize the enzymes and the mechanisms involved in cellulose degradation. Finally, we present the contribution of these bacteria to the host.
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Affiliation(s)
- Alicia Froidurot
- Université Bourgogne Franche–Comté, Institut Agro Dijon, PAM UMR A 02.102, Dijon, France,CONTACT Alicia Froidurot Université Bourgogne Franche–Comté, Institut Agro Dijon, PAM UMR A 02.102Dijon, France
| | - Véronique Julliand
- Université Bourgogne Franche–Comté, Institut Agro Dijon, PAM UMR A 02.102, Dijon, France
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Abstract
Buffalo is an important livestock species. Here, we present a comprehensive metagenomic survey of the microbial communities along the buffalo digestive tract. We analysed 695 samples covering eight different sites in three compartments (four-chambered stomach, intestine, and rectum). We mapped ~85% of the raw sequence reads to 4,960 strain-level metagenome-assembled genomes (MAGs) and 3,255 species-level MAGs, 90% of which appear to correspond to new species. In addition, we annotated over 5.8 million nonredundant proteins from the MAGs. In comparison with the rumen microbiome of cattle, the buffalo microbiota seems to present greater potential for fibre degradation and less potential for methane production. Our catalogue of microbial genomes and the encoded proteins provides insights into microbial functions and interactions at distinct sites along the buffalo digestive tract.
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12
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Cabral L, Persinoti GF, Paixão DAA, Martins MP, Morais MAB, Chinaglia M, Domingues MN, Sforca ML, Pirolla RAS, Generoso WC, Santos CA, Maciel LF, Terrapon N, Lombard V, Henrissat B, Murakami MT. Gut microbiome of the largest living rodent harbors unprecedented enzymatic systems to degrade plant polysaccharides. Nat Commun 2022; 13:629. [PMID: 35110564 PMCID: PMC8810776 DOI: 10.1038/s41467-022-28310-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 01/14/2022] [Indexed: 12/12/2022] Open
Abstract
The largest living rodent, capybara, can efficiently depolymerize and utilize lignocellulosic biomass through microbial symbiotic mechanisms yet elusive. Herein, we elucidate the microbial community composition, enzymatic systems and metabolic pathways involved in the conversion of dietary fibers into short-chain fatty acids, a main energy source for the host. In this microbiota, the unconventional enzymatic machinery from Fibrobacteres seems to drive cellulose degradation, whereas a diverse set of carbohydrate-active enzymes from Bacteroidetes, organized in polysaccharide utilization loci, are accounted to tackle complex hemicelluloses typically found in gramineous and aquatic plants. Exploring the genetic potential of this community, we discover a glycoside hydrolase family of β-galactosidases (named as GH173), and a carbohydrate-binding module family (named as CBM89) involved in xylan binding that establishes an unprecedented three-dimensional fold among associated modules to carbohydrate-active enzymes. Together, these results demonstrate how the capybara gut microbiota orchestrates the depolymerization and utilization of plant fibers, representing an untapped reservoir of enzymatic mechanisms to overcome the lignocellulose recalcitrance, a central challenge toward a sustainable and bio-based economy.
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Affiliation(s)
- Lucelia Cabral
- Brazilian Biorenewables National Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, SP, Brazil
| | - Gabriela F Persinoti
- Brazilian Biorenewables National Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, SP, Brazil.
| | - Douglas A A Paixão
- Brazilian Biorenewables National Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, SP, Brazil
| | - Marcele P Martins
- Brazilian Biorenewables National Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, SP, Brazil
- Graduate Program in Functional and Molecular Biology, Institute of Biology, University of Campinas, Campinas, SP, Brazil
| | - Mariana A B Morais
- Brazilian Biorenewables National Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, SP, Brazil
| | - Mariana Chinaglia
- Brazilian Biorenewables National Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, SP, Brazil
- Graduate Program in Functional and Molecular Biology, Institute of Biology, University of Campinas, Campinas, SP, Brazil
| | - Mariane N Domingues
- Brazilian Biorenewables National Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, SP, Brazil
| | - Mauricio L Sforca
- Brazilian Biosciences National Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, SP, Brazil
| | - Renan A S Pirolla
- Brazilian Biorenewables National Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, SP, Brazil
| | - Wesley C Generoso
- Brazilian Biorenewables National Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, SP, Brazil
| | - Clelton A Santos
- Brazilian Biorenewables National Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, SP, Brazil
| | - Lucas F Maciel
- Brazilian Biorenewables National Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, SP, Brazil
| | - Nicolas Terrapon
- The Institut National de la Recherche Agronomique, USC 1408 AFMB, 13288, Marseille, France
- Architecture et Fonction des Macromolécules Biologiques, CNRS, Aix-Marseille Université, Marseille, France
| | - Vincent Lombard
- The Institut National de la Recherche Agronomique, USC 1408 AFMB, 13288, Marseille, France
- Architecture et Fonction des Macromolécules Biologiques, CNRS, Aix-Marseille Université, Marseille, France
| | - Bernard Henrissat
- Department of Biotechnology and Biomedicine (DTU Bioengineering), Technical University of Denmark, 2800 Kgs, Lyngby, Denmark
- Department of Biological Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Mario T Murakami
- Brazilian Biorenewables National Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, SP, Brazil.
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Rico JL, Reardon KF, De Long SK. Inoculum microbiome composition impacts fatty acid product profile from cellulosic feedstock. BIORESOURCE TECHNOLOGY 2021; 323:124532. [PMID: 33422791 DOI: 10.1016/j.biortech.2020.124532] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Revised: 12/07/2020] [Accepted: 12/08/2020] [Indexed: 06/12/2023]
Abstract
Conversion of organic wastes to fatty acids rather than methane through anaerobic digestion-based technologies has considerable promise. However, the relationships between microbiome structure and fatty acids produced from cellulosic feedstocks are not well understood. This study investigated the nature of those relationships for anaerobic digester sludge, bison rumen, and cattle rumen inocula grown on cellulose. Acetic acid production was highest in anaerobic sludge reactors, while propionic acid production was highest in cattle rumen reactors. Butyric and pentanoic acid were produced at the highest rates in bison rumen before Day 5. Reactor microbiomes remained distinct, despite identical operating conditions. Novel associations linked Alistipes with butyric acid production and Eubacterium nodatum and Clostridiales bacterium with pentanoic acid production. This study provides new insights into the ability of microbiomes to convert cellulose to different fatty acid mixtures and adds impetus for the rewiring of anaerobic digestion to generate high-value products.
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Affiliation(s)
- Jorge L Rico
- Department of Civil and Environmental Engineering, Colorado State University, 1301 Campus Delivery, Fort Collins, CO 80523, USA.
| | - Kenneth F Reardon
- Department of Chemical and Biological Engineering, Colorado State University, 1301 Campus Delivery, Fort Collins, CO 80523, USA.
| | - Susan K De Long
- Department of Civil and Environmental Engineering, Colorado State University, 1301 Campus Delivery, Fort Collins, CO 80523, USA.
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14
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Rozman V, Accetto T, Duncan SH, Flint HJ, Vodovnik M. Type IV pili are widespread among non-pathogenic Gram-positive gut bacteria with diverse carbohydrate utilization patterns. Environ Microbiol 2021; 23:1527-1540. [PMID: 33331146 DOI: 10.1111/1462-2920.15362] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 12/15/2020] [Indexed: 12/23/2022]
Abstract
Type IV pili (T4P) are bacterial surface-exposed appendages that have been extensively studied in Gram-negative pathogenic bacteria. Despite recent sequencing efforts, little is known regarding these structures in non-pathogenic anaerobic Gram-positive species, particularly commensals of the mammalian gut. Early studies revealed that T4P in two ruminal Gram-positive species are associated with growth on cellulose, suggesting possible associations of T4P with substrate utilization patterns. In the present study, genome sequences of 118 taxonomically diverse, mainly Gram-positive, bacterial strains isolated from anaerobic (gastrointestinal) environments, have been analysed. The genes likely to be associated with T4P biogenesis were analysed and grouped according to T4P genetic organization. In parallel, consortia of Carbohydrate Active enZYmes (CAZymes) were also analysed and used to predict carbohydrate utilization abilities of selected strains. The predictive power of this approach was additionally confirmed by experimental assessment of substrate-related growth patterns of selected strains. Our analysis revealed that T4P systems with diverse genetic organization are widespread among Gram-positive anaerobic non-pathogenic bacteria isolated from different environments, belonging to two phylogenetically distantly related phyla: Firmicutes and Actinobacteria.
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Affiliation(s)
- Vita Rozman
- Chair of Microbiology and Microbial Biotechnology, Biotechnical Faculty, University of Ljubljana, Domžale, Slovenia
| | - Tomaž Accetto
- Chair of Microbiology and Microbial Biotechnology, Biotechnical Faculty, University of Ljubljana, Domžale, Slovenia
| | - Sylvia H Duncan
- Gut Health Group, Rowett Institute, University of Aberdeen, Aberdeen, UK
| | - Harry J Flint
- Gut Health Group, Rowett Institute, University of Aberdeen, Aberdeen, UK
| | - Maša Vodovnik
- Chair of Microbiology and Microbial Biotechnology, Biotechnical Faculty, University of Ljubljana, Domžale, Slovenia
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15
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Jiang Y, Ogunade I, Pech-Cervantes A, Fan P, Li X, Kim D, Arriola K, Poindexter M, Jeong K, Vyas D, Adesogan A. Effect of sequestering agents based on a Saccharomyces cerevisiae fermentation product and clay on the ruminal bacterial community of lactating dairy cows challenged with dietary aflatoxin B1. J Dairy Sci 2020; 103:1431-1447. [DOI: 10.3168/jds.2019-16851] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 09/26/2019] [Indexed: 11/19/2022]
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16
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Raut MP, Couto N, Karunakaran E, Biggs CA, Wright PC. Deciphering the unique cellulose degradation mechanism of the ruminal bacterium Fibrobacter succinogenes S85. Sci Rep 2019; 9:16542. [PMID: 31719545 PMCID: PMC6851124 DOI: 10.1038/s41598-019-52675-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Accepted: 10/22/2019] [Indexed: 02/04/2023] Open
Abstract
Fibrobacter succinogenes S85, isolated from the rumen of herbivores, is capable of robust lignocellulose degradation. However, the mechanism by which it achieves this is not fully elucidated. In this study, we have undertaken the most comprehensive quantitative proteomic analysis, to date, of the changes in the cell envelope protein profile of F. succinogenes S85 in response to growth on cellulose. Our results indicate that the cell envelope proteome undergoes extensive rearrangements to accommodate the cellulolytic degradation machinery, as well as associated proteins involved in adhesion to cellulose and transport and metabolism of cellulolytic products. Molecular features of the lignocellulolytic enzymes suggest that the Type IX secretion system is involved in the translocation of these enzymes to the cell envelope. Finally, we demonstrate, for the first time, that cyclic-di-GMP may play a role in mediating catabolite repression, thereby facilitating the expression of proteins involved in the adhesion to lignocellulose and subsequent lignocellulose degradation and utilisation. Understanding the fundamental aspects of lignocellulose degradation in F. succinogenes will aid the development of advanced lignocellulosic biofuels.
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Affiliation(s)
- Mahendra P Raut
- The ChELSI Institute, Department of Chemical and Biological Engineering, University of Sheffield, Mappin Street, Sheffield, S1 3JD, UK
| | - Narciso Couto
- The ChELSI Institute, Department of Chemical and Biological Engineering, University of Sheffield, Mappin Street, Sheffield, S1 3JD, UK.,Centre for Applied Pharmacokinetic Research, University of Manchester, Stopford Building, Oxford Road, Manchester, M13 9PT, UK
| | - Esther Karunakaran
- The ChELSI Institute, Department of Chemical and Biological Engineering, University of Sheffield, Mappin Street, Sheffield, S1 3JD, UK
| | - Catherine A Biggs
- School of Engineering, Faculty of Science, Agriculture & Engineering, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK
| | - Phillip C Wright
- School of Engineering, Faculty of Science, Agriculture & Engineering, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK.
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Moraïs S, Mizrahi I. Islands in the stream: from individual to communal fiber degradation in the rumen ecosystem. FEMS Microbiol Rev 2019; 43:362-379. [PMID: 31050730 PMCID: PMC6606855 DOI: 10.1093/femsre/fuz007] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2019] [Accepted: 04/05/2019] [Indexed: 12/20/2022] Open
Abstract
The herbivore rumen ecosystem constitutes an extremely efficient degradation machinery for the intricate chemical structure of fiber biomass, thus, enabling the hosting animal to digest its feed. The challenging task of deconstructing and metabolizing fiber is performed by microorganisms inhabiting the rumen. Since most of the ingested feed is comprised of plant fiber, these fiber-degrading microorganisms are of cardinal importance to the ecology of the rumen microbial community and to the hosting animal, and have a great impact on our environment and food sustainability. We summarize herein the enzymological fundamentals of fiber degradation, how the genes encoding these enzymes are spread across fiber-degrading microbes, and these microbes' interactions with other members of the rumen microbial community and potential effect on community structure. An understanding of these concepts has applied value for agriculture and our environment, and will also contribute to a better understanding of microbial ecology and evolution in anaerobic ecosystems.
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Affiliation(s)
- Sarah Moraïs
- Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Sderot Ben Gurion 1, Beer-Sheva 8499000, Israel
| | - Itzhak Mizrahi
- Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Sderot Ben Gurion 1, Beer-Sheva 8499000, Israel
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18
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de Paula RG, Antoniêto ACC, Nogueira KMV, Ribeiro LFC, Rocha MC, Malavazi I, Almeida F, Silva RN. Extracellular vesicles carry cellulases in the industrial fungus Trichoderma reesei. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:146. [PMID: 31223336 PMCID: PMC6570945 DOI: 10.1186/s13068-019-1487-7] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 06/07/2019] [Indexed: 05/21/2023]
Abstract
BACKGROUND Trichoderma reesei is the most important industrial producer of lignocellulolytic enzymes. These enzymes play an important role in biomass degradation leading to novel applications of this fungus in the biotechnology industry, specifically biofuel production. The secretory pathway of fungi is responsible for transporting proteins addressed to different cellular locations involving some cellular endomembrane systems. Although protein secretion is an extremely efficient process in T. reesei, the mechanisms underlying protein secretion have remained largely uncharacterized in this organism. RESULTS Here, we report for the first time the isolation and characterization of T. reesei extracellular vesicles (EVs). Using proteomic analysis under cellulose culture condition, we have confidently identified 188 vesicular proteins belonging to different functional categories. Also, we characterized EVs production using transmission electron microscopy in combination with light scattering analysis. Biochemical assays revealed that T. reesei extracellular vesicles have an enrichment of filter paper (FPase) and β-glucosidase activities in purified vesicles from 24, 72 and 96, and 72 and 96 h, respectively. Furthermore, our results showed that there is a slight enrichment of small RNAs inside the vesicles after 96 h and 120 h, and presence of hsp proteins inside the vesicles purified from T. reesei grown in the presence of cellulose. CONCLUSIONS This work points to important insights into a better understanding of the cellular mechanisms underlying the regulation of cellulolytic enzyme secretion in this fungus.
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Affiliation(s)
- Renato Graciano de Paula
- Department of Biochemistry and Immunology, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, São Paulo, 14049-900 Brazil
| | - Amanda Cristina Campos Antoniêto
- Department of Biochemistry and Immunology, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, São Paulo, 14049-900 Brazil
| | - Karoline Maria Vieira Nogueira
- Department of Biochemistry and Immunology, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, São Paulo, 14049-900 Brazil
| | - Liliane Fraga Costa Ribeiro
- Department of Biochemistry and Immunology, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, São Paulo, 14049-900 Brazil
| | - Marina Campos Rocha
- Departamento de Genética e Evolução, Centro de Ciências Biológicas e da Saúde, Universidade Federal de São Carlos, São Paulo, Brazil
| | - Iran Malavazi
- Departamento de Genética e Evolução, Centro de Ciências Biológicas e da Saúde, Universidade Federal de São Carlos, São Paulo, Brazil
| | - Fausto Almeida
- Department of Biochemistry and Immunology, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, São Paulo, 14049-900 Brazil
| | - Roberto Nascimento Silva
- Department of Biochemistry and Immunology, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, São Paulo, 14049-900 Brazil
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19
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Petri RM, Münnich M, Zebeli Q, Klevenhusen F. Graded replacement of corn grain with molassed sugar beet pulp modulates the fecal microbial community and hindgut fermentation profile in lactating dairy cows. J Dairy Sci 2019; 102:5019-5030. [PMID: 30928269 DOI: 10.3168/jds.2018-15704] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Accepted: 02/05/2019] [Indexed: 01/21/2023]
Abstract
High starch lactation diets not only enhance the risk of subacute ruminal acidosis but also of hindgut acidosis, which increases the risk of dysbiosis and the depression of fiber degradation. We recently showed that replacing corn with molassed sugar beet pulp (Bp) improved fiber degradation in high-producing dairy cattle, possibly because of an improvement of rumen and hindgut conditions for microbes by Bp feeding. However, little is known about the effects of high inclusion rates of Bp on hindgut microbes and fermentation. Thus fecal grab samples were taken from 18 high-yielding Simmental cows after 28 d of feeding 3 different levels of Bp (n = 6) for bacterial 16S rRNA amplicon sequencing. In addition, the reticular pH was continuously monitored with indwelling sensors and eating and ruminating behavior was evaluated with noseband sensors. The Bp inclusion rates were 0 g/kg (i.e., no Bp inclusion as control, CON), 120 g/kg (12Bp), or 240 g/kg (24Bp) replacing corn grain and limestone on a dry matter basis. The amount of time spent eating and ruminating was unaffected by Bp level, and the daily fluctuation in the reticular pH was reduced by 25% with Bp inclusion from 0.8 in the CON diet to 0.6 in 24Bp fed animals. Also, the fecal pH tended to increase with dietary Bp inclusion. Fecal acetate production showed a quadratic tendency with the lowest concentration (58.9%) of the total short-chain fatty acid in the 12Bp treatment. Inclusion of Bp up to 24% of the diet decreased the fecal butyrate proportion by 27%. The Shannon diversity index was increased from 5.50 to 8.09 with dietary Bp inclusion indicating increased species diversity. Of the 200 most abundant operational taxonomic units, 25 were increased by dietary Bp inclusion, whereas 15 were decreased and 7 were quadratically affected. The second most abundant group was proposed taxon "CF231" of the family Paraprevotellaceae. Although it accounted for only 2.52% of the operational taxonomic units in the CON diet, it was increased by 64% with dietary Bp inclusion. The largest relative change in the abundance was found for the genus Fibrobacter that increased more than 14-fold from 0.04% (CON) to 0.66% (24Bp). In conclusion, feeding molassed sugar beet pulp as partial substitution of corn up to 240 g/kg is a viable alternative that promotes ruminal and hindgut fermentation by supporting physiological pH and bacterial diversity.
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Affiliation(s)
- Renee Maxine Petri
- Institute of Animal Nutrition and Functional Plant Compounds, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine Vienna, 1210 Vienna, Austria.
| | - Matthias Münnich
- Institute of Animal Nutrition and Functional Plant Compounds, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine Vienna, 1210 Vienna, Austria
| | - Qendrim Zebeli
- Institute of Animal Nutrition and Functional Plant Compounds, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine Vienna, 1210 Vienna, Austria
| | - Fenja Klevenhusen
- Institute of Animal Nutrition and Functional Plant Compounds, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine Vienna, 1210 Vienna, Austria.
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20
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Neumann AP, Suen G. The Phylogenomic Diversity of Herbivore-Associated Fibrobacter spp. Is Correlated to Lignocellulose-Degrading Potential. mSphere 2018; 3:e00593-18. [PMID: 30541780 PMCID: PMC6291624 DOI: 10.1128/msphere.00593-18] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Accepted: 11/29/2018] [Indexed: 12/30/2022] Open
Abstract
Members of the genus Fibrobacter are cellulose-degrading bacteria and common constituents of the gastrointestinal microbiota of herbivores. Although considerable phylogenetic diversity is observed among members of this group, few functional differences explaining the distinct ecological distributions of specific phylotypes have been described. In this study, we sequenced and performed a comparative analysis of whole genomes from 38 novel Fibrobacter strains against the type strains for the two formally described Fibrobacter species F. succinogenes strain S85 and F. intestinalis strain NR9. Significant differences in the number of genes encoding carbohydrate-active enzyme families involved in plant cell wall polysaccharide degradation were observed among Fibrobacter phylotypes. F. succinogenes genomes were consistently enriched in genes encoding carbohydrate-active enzymes compared to those of F. intestinalis strains. Moreover, genomes of F. succinogenes phylotypes that are dominant in the rumen had significantly more genes annotated to major families involved in hemicellulose degradation (e.g., CE6, GH10, and GH43) than did the genomes of F. succinogenes phylotypes typically observed in the lower gut of large hindgut-fermenting herbivores such as horses. Genes encoding a putative urease were also identified in 12 of the Fibrobacter genomes, which were primarily isolated from hindgut-fermenting hosts. Screening for growth on urea as the sole source of nitrogen provided strong evidence that the urease was active in these strains. These results represent the strongest evidence reported to date for specific functional differences contributing to the ecology of Fibrobacter spp. in the herbivore gut.IMPORTANCE The herbivore gut microbiome is incredibly diverse, and a functional understanding of this diversity is needed to more reliably manipulate this community for specific gain, such as increased production in ruminant livestock. Microbial degraders of plant cell wall polysaccharides in the herbivore gut, particularly Fibrobacter spp., are of fundamental importance to their hosts for digestion of a diet consisting primarily of recalcitrant plant fibers. Considerable phylogenetic diversity exists among members of the genus Fibrobacter, but much of this diversity remains cryptic. Here, we used comparative genomics, applied to a diverse collection of recently isolated Fibrobacter strains, to identify a robust association between carbohydrate-active enzyme gene content and the Fibrobacter phylogeny. Our results provide the strongest evidence reported to date for functional differences among Fibrobacter phylotypes associated with either the rumen or the hindgut and emphasize the general significance of carbohydrate-active enzymes in the evolution of fiber-degrading bacteria.
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Affiliation(s)
- Anthony P Neumann
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Garret Suen
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
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21
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Proteomic Dissection of the Cellulolytic Machineries Used by Soil-Dwelling Bacteroidetes. mSystems 2018; 3:mSystems00240-18. [PMID: 30505945 PMCID: PMC6247017 DOI: 10.1128/msystems.00240-18] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Accepted: 11/02/2018] [Indexed: 11/20/2022] Open
Abstract
Bacteria of the phylum Bacteroidetes are regarded as highly efficient carbohydrate metabolizers, but most species are limited to (semi)soluble glycans. The soil Bacteroidetes species Cytophaga hutchinsonii and Sporocytophaga myxococcoides have long been known as efficient cellulose metabolizers, but neither species conforms to known cellulolytic mechanisms. Both species require contact with their substrate but do not encode cellulosomal systems of cell surface-attached enzyme complexes or the polysaccharide utilization loci found in many other Bacteroidetes species. Here, we have fractionated the cellular compartments of each species from cultures growing on crystalline cellulose and pectin, respectively, and analyzed them using label-free quantitative proteomics as well as enzymatic activity assays. The combined results enabled us to highlight enzymes likely to be important for cellulose conversion and to infer their cellular localization. The combined proteomes represent a wide array of putative cellulolytic enzymes and indicate specific and yet highly redundant mechanisms for cellulose degradation. Of the putative endoglucanases, especially enzymes of hitherto-unstudied glycoside hydrolase family, 8 were abundant, indicating an overlooked important role during cellulose metabolism. Furthermore, both species generated a large number of abundant hypothetical proteins during cellulose conversion, providing a treasure trove of targets for future enzymology studies. IMPORTANCE Cellulose is the most abundant renewable polymer on earth, but its recalcitrance limits highly efficient conversion methods for energy-related and material applications. Though microbial cellulose conversion has been studied for decades, recent advances showcased that large knowledge gaps still exist. Bacteria of the phylum Bacteroidetes are regarded as highly efficient carbohydrate metabolizers, but most species are limited to (semi)soluble glycans. A few species, including the soil bacteria C. hutchinsonii and S. myxococcoides, are regarded as cellulose specialists, but their cellulolytic mechanisms are not understood, as they do not conform to the current models for enzymatic cellulose turnover. By unraveling the proteome setups of these two bacteria during growth on both crystalline cellulose and pectin, we have taken a significant step forward in understanding their idiosyncratic mode of cellulose conversion. This report provides a plethora of new enzyme targets for improved biomass conversion.
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22
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Naas AE, Solden LM, Norbeck AD, Brewer H, Hagen LH, Heggenes IM, McHardy AC, Mackie RI, Paša-Tolić L, Arntzen MØ, Eijsink VGH, Koropatkin NM, Hess M, Wrighton KC, Pope PB. "Candidatus Paraporphyromonas polyenzymogenes" encodes multi-modular cellulases linked to the type IX secretion system. MICROBIOME 2018; 6:44. [PMID: 29490697 PMCID: PMC5831590 DOI: 10.1186/s40168-018-0421-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 02/07/2018] [Indexed: 05/07/2023]
Abstract
BACKGROUND In nature, obligate herbivorous ruminants have a close symbiotic relationship with their gastrointestinal microbiome, which proficiently deconstructs plant biomass. Despite decades of research, lignocellulose degradation in the rumen has thus far been attributed to a limited number of culturable microorganisms. Here, we combine meta-omics and enzymology to identify and describe a novel Bacteroidetes family ("Candidatus MH11") composed entirely of uncultivated strains that are predominant in ruminants and only distantly related to previously characterized taxa. RESULTS The first metabolic reconstruction of Ca. MH11-affiliated genome bins, with a particular focus on the provisionally named "Candidatus Paraporphyromonas polyenzymogenes", illustrated their capacity to degrade various lignocellulosic substrates via comprehensive inventories of singular and multi-modular carbohydrate active enzymes (CAZymes). Closer examination revealed an absence of archetypical polysaccharide utilization loci found in human gut microbiota. Instead, we identified many multi-modular CAZymes putatively secreted via the Bacteroidetes-specific type IX secretion system (T9SS). This included cellulases with two or more catalytic domains, which are modular arrangements that are unique to Bacteroidetes species studied to date. Core metabolic proteins from Ca. P. polyenzymogenes were detected in metaproteomic data and were enriched in rumen-incubated plant biomass, indicating that active saccharification and fermentation of complex carbohydrates could be assigned to members of this novel family. Biochemical analysis of selected Ca. P. polyenzymogenes CAZymes further iterated the cellulolytic activity of this hitherto uncultured bacterium towards linear polymers, such as amorphous and crystalline cellulose as well as mixed linkage β-glucans. CONCLUSION We propose that Ca. P. polyenzymogene genotypes and other Ca. MH11 members actively degrade plant biomass in the rumen of cows, sheep and most likely other ruminants, utilizing singular and multi-domain catalytic CAZymes secreted through the T9SS. The discovery of a prominent role of multi-modular cellulases in the Gram-negative Bacteroidetes, together with similar findings for Gram-positive cellulosomal bacteria (Ruminococcus flavefaciens) and anaerobic fungi (Orpinomyces sp.), suggests that complex enzymes are essential and have evolved within all major cellulolytic dominions inherent to the rumen.
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Affiliation(s)
- A E Naas
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Post Office Box 5003, 1432, Ås, Norway
| | - L M Solden
- Department of Microbiology, The Ohio State University, Columbus, OH, 43201, USA
| | - A D Norbeck
- Environmental and Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA, 99354, USA
| | - H Brewer
- Environmental and Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA, 99354, USA
| | - L H Hagen
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Post Office Box 5003, 1432, Ås, Norway
| | - I M Heggenes
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Post Office Box 5003, 1432, Ås, Norway
| | - A C McHardy
- Computational Biology of Infection Research, Helmholtz Centre for Infection Research, Inhoffenstraβe 7, 38124, Braunschweig, Germany
| | - R I Mackie
- Institute for Genomic Biology and Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - L Paša-Tolić
- Environmental and Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA, 99354, USA
| | - M Ø Arntzen
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Post Office Box 5003, 1432, Ås, Norway
| | - V G H Eijsink
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Post Office Box 5003, 1432, Ås, Norway
| | - N M Koropatkin
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - M Hess
- Department of Animal Science, University of California, Davis, CA, 95616, USA
| | - K C Wrighton
- Department of Microbiology, The Ohio State University, Columbus, OH, 43201, USA
| | - P B Pope
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Post Office Box 5003, 1432, Ås, Norway.
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Neumann AP, Weimer PJ, Suen G. A global analysis of gene expression in Fibrobacter succinogenes S85 grown on cellulose and soluble sugars at different growth rates. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:295. [PMID: 30386432 PMCID: PMC6204037 DOI: 10.1186/s13068-018-1290-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Accepted: 10/15/2018] [Indexed: 05/04/2023]
Abstract
BACKGROUND Cellulose is the most abundant biological polymer on earth, making it an attractive substrate for the production of next-generation biofuels and commodity chemicals. However, the economics of cellulose utilization are currently unfavorable due to a lack of efficient methods for its hydrolysis. Fibrobacter succinogenes strain S85, originally isolated from the bovine rumen, is among the most actively cellulolytic mesophilic bacteria known, producing succinate as its major fermentation product. In this study, we examined the transcriptome of F. succinogenes S85 grown in continuous culture at several dilution rates on cellulose, cellobiose, or glucose to gain a system-level understanding of cellulose degradation by this bacterium. RESULTS Several patterns of gene expression were observed for the major cellulases produced by F. succinogenes S85. A large proportion of cellulase genes were constitutively expressed, including the gene encoding for Cel51A, the major cellulose-binding endoglucanase produced by this bacterium. Moreover, other cellulase genes displayed elevated expression during growth on cellulose relative to growth on soluble sugars. Growth rate had a strong effect on global gene expression, particularly with regard to genes predicted to encode carbohydrate-binding modules and glycoside hydrolases implicated in hemicellulose degradation. Expression of hemicellulase genes was tightly regulated, with these genes displaying elevated expression only during slow growth on soluble sugars. Clear differences in gene expression were also observed between adherent and planktonic populations within continuous cultures growing on cellulose. CONCLUSIONS This work emphasizes the complexity of the fiber-degrading system utilized by F. succinogenes S85, and reinforces the complementary role of hemicellulases for accessing cellulose by these bacteria. We report for the first time evidence of global differences in gene expression between adherent and planktonic populations of an anaerobic bacterium growing on cellulose at steady state during continuous cultivation. Finally, our results also highlight the importance of controlling for growth rate in investigations of gene expression.
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Affiliation(s)
- Anthony P. Neumann
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI USA
| | - Paul J. Weimer
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI USA
- Agricultural Research Service, United States Department of Agriculture, Madison, WI USA
| | - Garret Suen
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI USA
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24
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Agematu H, Takahashi T, Hamano Y. Continuous volatile fatty acid production from lignocellulosic biomass by a novel rumen-mimetic bioprocess. J Biosci Bioeng 2017; 124:528-533. [DOI: 10.1016/j.jbiosc.2017.06.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 06/12/2017] [Accepted: 06/16/2017] [Indexed: 11/26/2022]
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25
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Boonsaen P, Kinjo M, Sawanon S, Suzuki Y, Koike S, Kobayashi Y. Partial characterization of phylogeny, ecology and function of the fibrolytic bacteriumRuminococcus flavefaciens OS14, newly isolated from the rumen of swamp buffalo. Anim Sci J 2017; 89:377-385. [DOI: 10.1111/asj.12927] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2017] [Accepted: 08/17/2017] [Indexed: 11/30/2022]
Affiliation(s)
- Phoompong Boonsaen
- Department of Animal Science; Faculty of Agriculture at Kamphaeng Saen; Kasetsart University; Nakhon Pathom Thailand
- Center for Advanced Studies for Agriculture and Food; Kasetsart University Institute for Advanced Studies; Kasetsart University; Bangkok Thailand
| | - Madoka Kinjo
- Laboratory of Animal Function and Nutrition; Research Faculty of Agriculture; Hokkaido University; Sapporo Japan
| | - Suriya Sawanon
- Department of Animal Science; Faculty of Agriculture at Kamphaeng Saen; Kasetsart University; Nakhon Pathom Thailand
- Center for Advanced Studies for Agriculture and Food; Kasetsart University Institute for Advanced Studies; Kasetsart University; Bangkok Thailand
| | - Yutaka Suzuki
- Laboratory of Animal Function and Nutrition; Research Faculty of Agriculture; Hokkaido University; Sapporo Japan
| | - Satoshi Koike
- Laboratory of Animal Function and Nutrition; Research Faculty of Agriculture; Hokkaido University; Sapporo Japan
| | - Yasuo Kobayashi
- Laboratory of Animal Function and Nutrition; Research Faculty of Agriculture; Hokkaido University; Sapporo Japan
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26
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The unusual cellulose utilization system of the aerobic soil bacterium Cytophaga hutchinsonii. Appl Microbiol Biotechnol 2017; 101:7113-7127. [PMID: 28849247 DOI: 10.1007/s00253-017-8467-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Accepted: 08/05/2017] [Indexed: 10/19/2022]
Abstract
Cellulolytic microorganisms play important roles in global carbon cycling and have evolved diverse strategies to digest cellulose. Some are 'generous,' releasing soluble sugars from cellulose extracellularly to feed both themselves and their neighbors. The gliding soil bacterium Cytophaga hutchinsonii exhibits a more 'selfish' strategy. It digests crystalline cellulose using cell-associated cellulases and releases little soluble sugar outside of the cell. The mechanism of C. hutchinsonii cellulose utilization is still poorly understood. In this review, we discuss novel aspects of the C. hutchinsonii cellulolytic system. Recently developed genetic manipulation tools allowed the identification of proteins involved in C. hutchinsonii cellulose utilization. These include periplasmic and cell-surface endoglucanases and novel cellulose-binding proteins. The recently discovered type IX secretion system is needed for cellulose utilization and appears to deliver some of the cellulolytic enzymes and other proteins to the cell surface. The requirement for periplasmic endoglucanases for cellulose utilization is unusual and suggests that cello-oligomers must be imported across the outer membrane before being further digested. Cellobiohydrolases or other predicted processive cellulases that play important roles in many other cellulolytic bacteria appear to be absent in C. hutchinsonii. Cells of C. hutchinsonii attach to and glide along cellulose fibers, which may allow them to find sites most amenable to attack. A model of C. hutchinsonii cellulose utilization summarizing recent progress is proposed.
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27
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Lignocellulose-Degrading Microbial Communities in Landfill Sites Represent a Repository of Unexplored Biomass-Degrading Diversity. mSphere 2017; 2:mSphere00300-17. [PMID: 28776044 PMCID: PMC5541161 DOI: 10.1128/msphere.00300-17] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 07/19/2017] [Indexed: 11/20/2022] Open
Abstract
The microbial conversion of lignocellulosic biomass for biofuel production represents a renewable alternative to fossil fuels. However, the discovery of new microbial enzymes with high activity is critical for improving biomass conversion processes. While attempts to identify superior lignocellulose-degrading enzymes have focused predominantly on the animal gut, biomass-degrading communities in landfill sites represent an unexplored resource of hydrolytic enzymes for biomass conversion. Here, we identified Firmicutes, Spirochaetes, and Fibrobacteres as key phyla in the landfill cellulolytic community, detecting 8,371 carbohydrate active enzymes (CAZymes) that represent at least three of the recognized strategies for cellulose decomposition. These data highlight substantial hydrolytic enzyme diversity in landfill sites as a source of new enzymes for biomass conversion. The microbial conversion of lignocellulosic biomass for biofuel production represents a renewable alternative to fossil fuels. However, the discovery of new microbial enzymes with high activity is critical for improving biomass conversion processes. While attempts to identify superior lignocellulose-degrading enzymes have focused predominantly on the animal gut, biomass-degrading communities in landfill sites represent an unexplored resource of hydrolytic enzymes for biomass conversion. Here, to address the paucity of information on biomass-degrading microbial diversity beyond the gastrointestinal tract, cellulose (cotton) “baits” were incubated in landfill leachate microcosms to enrich the landfill cellulolytic microbial community for taxonomic and functional characterization. Metagenome and 16S rRNA gene amplicon sequencing demonstrated the dominance of Firmicutes, Bacteroidetes, Spirochaetes, and Fibrobacteres in the landfill cellulolytic community. Functional metagenome analysis revealed 8,371 carbohydrate active enzymes (CAZymes) belonging to 244 CAZyme families. In addition to observing biomass-degrading enzymes of anaerobic bacterial “cellulosome” systems of members of the Firmicutes, we report the first detection of the Fibrobacter cellulase system and the Bacteroidetes polysaccharide utilization locus (PUL) in landfill sites. These data provide evidence for the presence of multiple mechanisms of biomass degradation in the landfill microbiome and highlight the extraordinary functional diversity of landfill microorganisms as a rich source of biomass-degrading enzymes of potential biotechnological significance. IMPORTANCE The microbial conversion of lignocellulosic biomass for biofuel production represents a renewable alternative to fossil fuels. However, the discovery of new microbial enzymes with high activity is critical for improving biomass conversion processes. While attempts to identify superior lignocellulose-degrading enzymes have focused predominantly on the animal gut, biomass-degrading communities in landfill sites represent an unexplored resource of hydrolytic enzymes for biomass conversion. Here, we identified Firmicutes, Spirochaetes, and Fibrobacteres as key phyla in the landfill cellulolytic community, detecting 8,371 carbohydrate active enzymes (CAZymes) that represent at least three of the recognized strategies for cellulose decomposition. These data highlight substantial hydrolytic enzyme diversity in landfill sites as a source of new enzymes for biomass conversion.
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28
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Ghali I, Sofyan A, Ohmori H, Shinkai T, Mitsumori M. Diauxic growth of Fibrobacter succinogenes S85 on cellobiose and lactose. FEMS Microbiol Lett 2017; 364:3966718. [DOI: 10.1093/femsle/fnx150] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 07/12/2017] [Indexed: 12/23/2022] Open
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29
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Arntzen MØ, Várnai A, Mackie RI, Eijsink VGH, Pope PB. Outer membrane vesicles from Fibrobacter succinogenes S85 contain an array of carbohydrate-active enzymes with versatile polysaccharide-degrading capacity. Environ Microbiol 2017; 19:2701-2714. [PMID: 28447389 DOI: 10.1111/1462-2920.13770] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 04/18/2017] [Indexed: 11/30/2022]
Abstract
Fibrobacter succinogenes is an anaerobic bacterium naturally colonising the rumen and cecum of herbivores where it utilizes an enigmatic mechanism to deconstruct cellulose into cellobiose and glucose, which serve as carbon sources for growth. Here, we illustrate that outer membrane vesicles (OMVs) released by F. succinogenes are enriched with carbohydrate-active enzymes and that intact OMVs were able to depolymerize a broad range of linear and branched hemicelluloses and pectin, despite the inability of F. succinogenes to utilize non-cellulosic (pentose) sugars for growth. We hypothesize that the degradative versatility of F. succinogenes OMVs is used to prime hydrolysis by destabilising the tight networks of polysaccharides intertwining cellulose in the plant cell wall, thus increasing accessibility of the target substrate for the host cell. This is supported by observations that OMV-pretreatment of the natural complex substrate switchgrass increased the catalytic efficiency of a commercial cellulose-degrading enzyme cocktail by 2.4-fold. We also show that the OMVs contain a putative multiprotein complex, including the fibro-slime protein previously found to be important in binding to crystalline cellulose. We hypothesize that this complex has a function in plant cell wall degradation, either by catalysing polysaccharide degradation itself, or by targeting the vesicles to plant biomass.
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Affiliation(s)
- Magnus Ø Arntzen
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | - Anikó Várnai
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | - Roderick I Mackie
- Institute for Genomic Biology, and Department of Animal Sciences, University of Illinois at Urbana-Champaign, IL, USA
| | - Vincent G H Eijsink
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | - Phillip B Pope
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
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30
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Comtet-Marre S, Parisot N, Lepercq P, Chaucheyras-Durand F, Mosoni P, Peyretaillade E, Bayat AR, Shingfield KJ, Peyret P, Forano E. Metatranscriptomics Reveals the Active Bacterial and Eukaryotic Fibrolytic Communities in the Rumen of Dairy Cow Fed a Mixed Diet. Front Microbiol 2017; 8:67. [PMID: 28197133 PMCID: PMC5281551 DOI: 10.3389/fmicb.2017.00067] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 01/10/2017] [Indexed: 12/31/2022] Open
Abstract
Ruminants have a unique ability to derive energy from the degradation of plant polysaccharides through the activity of the rumen microbiota. Although this process is well studied in vitro, knowledge gaps remain regarding the relative contribution of the microbiota members and enzymes in vivo. The present study used RNA-sequencing to reveal both the expression of genes encoding carbohydrate-active enzymes (CAZymes) by the rumen microbiota of a lactating dairy cow and the microorganisms forming the fiber-degrading community. Functional analysis identified 12,237 CAZymes, accounting for 1% of the transcripts. The CAZyme profile was dominated by families GH94 (cellobiose-phosphorylase), GH13 (amylase), GH43 and GH10 (hemicellulases), GH9 and GH48 (cellulases), PL11 (pectinase) as well as GH2 and GH3 (oligosaccharidases). Our data support the pivotal role of the most characterized fibrolytic bacteria (Prevotella, Ruminocccus and Fibrobacter), and highlight a substantial, although most probably underestimated, contribution of fungi and ciliate protozoa to polysaccharide degradation. Particularly these results may motivate further exploration of the role and the functions of protozoa in the rumen. Moreover, an important part of the fibrolytic bacterial community remains to be characterized since one third of the CAZyme transcripts originated from distantly related strains. These findings are used to highlight limitations of current metatranscriptomics approaches to understand the functional rumen microbial community and opportunities to circumvent them.
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Affiliation(s)
| | - Nicolas Parisot
- EA4678 CIDAM, Clermont Université, Université d'Auvergne Clermont-Ferrand, France
| | - Pascale Lepercq
- UR454 Unité de Microbiologie, INRA Saint-Genès-Champanelle, France
| | | | - Pascale Mosoni
- UR454 Unité de Microbiologie, INRA Saint-Genès-Champanelle, France
| | - Eric Peyretaillade
- EA4678 CIDAM, Clermont Université, Université d'Auvergne Clermont-Ferrand, France
| | - Ali R Bayat
- Nutritional Physiology, Green Technology, Natural Resources Institute Finland (Luke) Jokioinen, Finland
| | - Kevin J Shingfield
- Nutritional Physiology, Green Technology, Natural Resources Institute Finland (Luke)Jokioinen, Finland; Institute of Biological, Environmental and Rural Sciences, Aberystwyth UniversityAberystwyth, UK
| | - Pierre Peyret
- EA4678 CIDAM, Clermont Université, Université d'Auvergne Clermont-Ferrand, France
| | - Evelyne Forano
- UR454 Unité de Microbiologie, INRA Saint-Genès-Champanelle, France
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31
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Rosnow JJ, Anderson LN, Nair RN, Baker ES, Wright AT. Profiling microbial lignocellulose degradation and utilization by emergent omics technologies. Crit Rev Biotechnol 2016; 37:626-640. [PMID: 27439855 DOI: 10.1080/07388551.2016.1209158] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
The use of plant materials to generate renewable biofuels and other high-value chemicals is the sustainable and preferable option, but will require considerable improvements to increase the rate and efficiency of lignocellulose depolymerization. This review highlights novel and emerging technologies that are being developed and deployed to characterize the process of lignocellulose degradation. The review will also illustrate how microbial communities deconstruct and metabolize lignocellulose by identifying the necessary genes and enzyme activities along with the reaction products. These technologies include multi-omic measurements, cell sorting and isolation, nuclear magnetic resonance spectroscopy (NMR), activity-based protein profiling, and direct measurement of enzyme activity. The recalcitrant nature of lignocellulose necessitates the need to characterize the methods microbes employ to deconstruct lignocellulose to inform new strategies on how to greatly improve biofuel conversion processes. New technologies are yielding important insights into microbial functions and strategies employed to degrade lignocellulose, providing a mechanistic blueprint in order to advance biofuel production.
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Affiliation(s)
- Joshua J Rosnow
- a Biological Sciences Division , Pacific Northwest National Laboratory , Richland , WA , USA
| | - Lindsey N Anderson
- a Biological Sciences Division , Pacific Northwest National Laboratory , Richland , WA , USA
| | - Reji N Nair
- a Biological Sciences Division , Pacific Northwest National Laboratory , Richland , WA , USA
| | - Erin S Baker
- a Biological Sciences Division , Pacific Northwest National Laboratory , Richland , WA , USA
| | - Aaron T Wright
- a Biological Sciences Division , Pacific Northwest National Laboratory , Richland , WA , USA
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32
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Periplasmic Cytophaga hutchinsonii Endoglucanases Are Required for Use of Crystalline Cellulose as the Sole Source of Carbon and Energy. Appl Environ Microbiol 2016; 82:4835-4845. [PMID: 27260354 DOI: 10.1128/aem.01298-16] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 05/25/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED The soil bacterium Cytophaga hutchinsonii actively digests crystalline cellulose by a poorly understood mechanism. Genome analyses identified nine genes predicted to encode endoglucanases with roles in this process. No predicted cellobiohydrolases, which are usually involved in the utilization of crystalline cellulose, were identified. Chromosomal deletions were performed in eight of the endoglucanase-encoding genes: cel5A, cel5B, cel5C, cel9A, cel9B, cel9C, cel9E, and cel9F Each mutant retained the ability to digest crystalline cellulose, although the deletion of cel9C caused a modest decrease in cellulose utilization. Strains with multiple deletions were constructed to identify the critical cellulases. Cells of a mutant lacking both cel5B and cel9C were completely deficient in growth on cellulose. Cell fractionation and biochemical analyses indicate that Cel5B and Cel9C are periplasmic nonprocessive endoglucanases. The requirement of periplasmic endoglucanases for cellulose utilization suggests that cellodextrins are transported across the outer membrane during this process. Bioinformatic analyses predict that Cel5A, Cel9A, Cel9B, Cel9D, and Cel9E are secreted across the outer membrane by the type IX secretion system, which has been linked to cellulose utilization. These secreted endoglucanases may perform the initial digestion within amorphous regions on the cellulose fibers, releasing oligomers that are transported into the periplasm for further digestion by Cel5B and Cel9C. The results suggest that both cell surface and periplasmic endoglucanases are required for the growth of C. hutchinsonii on cellulose and that novel cell surface proteins may solubilize and transport cellodextrins across the outer membrane. IMPORTANCE The bacterium Cytophaga hutchinsonii digests crystalline cellulose by an unknown mechanism. It lacks processive cellobiohydrolases that are often involved in cellulose digestion. Critical cellulolytic enzymes were identified by genetic analyses. Intracellular (periplasmic) nonprocessive endoglucanases performed an important role in cellulose utilization. The results suggest a model involving partial digestion at the cell surface, solubilization and uptake of cellodextrins across the outer membrane by an unknown mechanism, and further digestion within the periplasm. The ability to sequester cellodextrins and digest them intracellularly may limit losses of soluble cellobiose to other organisms. C. hutchinsonii uses an unusual approach to digest cellulose and is a potential source of novel proteins to increase the efficiency of conversion of cellulose into soluble sugars and biofuels.
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