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Gladkov GV, Kimeklis AK, Afonin AM, Lisina TO, Orlova OV, Aksenova TS, Kichko AA, Pinaev AG, Andronov EE. The Structure of Stable Cellulolytic Consortia Isolated from Natural Lignocellulosic Substrates. Int J Mol Sci 2022; 23:ijms231810779. [PMID: 36142684 PMCID: PMC9501375 DOI: 10.3390/ijms231810779] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 08/31/2022] [Accepted: 09/04/2022] [Indexed: 10/27/2022] Open
Abstract
Recycling plant matter is one of the challenges facing humanity today and depends on efficient lignocellulose degradation. Although many bacterial strains from natural substrates demonstrate cellulolytic activities, the CAZymes (Carbohydrate-Active enZYmes) responsible for these activities are very diverse and usually distributed among different bacteria in one habitat. Thus, using microbial consortia can be a solution to rapid and effective decomposition of plant biomass. Four cellulolytic consortia were isolated from enrichment cultures from composting natural lignocellulosic substrates—oat straw, pine sawdust, and birch leaf litter. Enrichment cultures facilitated growth of similar, but not identical cellulose-decomposing bacteria from different substrates. Major components in all consortia were from Proteobacteria, Actinobacteriota and Bacteroidota, but some were specific for different substrates—Verrucomicrobiota and Myxococcota from straw, Planctomycetota from sawdust and Firmicutes from leaf litter. While most members of the consortia were involved in the lignocellulose degradation, some demonstrated additional metabolic activities. Consortia did not differ in the composition of CAZymes genes, but rather in axillary functions, such as ABC-transporters and two-component systems, usually taxon-specific and associated with CAZymes. Our findings show that enrichment cultures can provide reproducible cellulolytic consortia from various lignocellulosic substrates, the stability of which is ensured by tight microbial relations between its components.
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Affiliation(s)
- Grigory V. Gladkov
- All-Russian Research Institute of Agricultural Microbiology, 196608 Saint Petersburg, Russia
- Correspondence: ; Tel.: +7-921-402-65-16
| | - Anastasiia K. Kimeklis
- All-Russian Research Institute of Agricultural Microbiology, 196608 Saint Petersburg, Russia
- Department of Applied Ecology, Saint-Petersburg State University, 199034 Saint Petersburg, Russia
| | - Alexey M. Afonin
- All-Russian Research Institute of Agricultural Microbiology, 196608 Saint Petersburg, Russia
| | - Tatiana O. Lisina
- All-Russian Research Institute of Agricultural Microbiology, 196608 Saint Petersburg, Russia
| | - Olga V. Orlova
- All-Russian Research Institute of Agricultural Microbiology, 196608 Saint Petersburg, Russia
| | - Tatiana S. Aksenova
- All-Russian Research Institute of Agricultural Microbiology, 196608 Saint Petersburg, Russia
| | - Arina A. Kichko
- All-Russian Research Institute of Agricultural Microbiology, 196608 Saint Petersburg, Russia
| | - Alexander G. Pinaev
- All-Russian Research Institute of Agricultural Microbiology, 196608 Saint Petersburg, Russia
| | - Evgeny E. Andronov
- All-Russian Research Institute of Agricultural Microbiology, 196608 Saint Petersburg, Russia
- Dokuchaev Soil Science Institute, 119017 Moscow, Russia
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Deng Y, Wang SY. Sorption of Cellulases in Biofilm Enhances Cellulose Degradation by Bacillus subtilis. Microorganisms 2022; 10:microorganisms10081505. [PMID: 35893563 PMCID: PMC9329931 DOI: 10.3390/microorganisms10081505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 07/11/2022] [Accepted: 07/22/2022] [Indexed: 02/04/2023] Open
Abstract
Biofilm commonly forms on the surfaces of cellulosic biomass but its roles in cellulose degradation remain largely unexplored. We used Bacillus subtilis to study possible mechanisms and the contributions of two major biofilm components, extracellular polysaccharides (EPS) and TasA protein, to submerged biofilm formation on cellulose and its degradation. We found that biofilm produced by B. subtilis is able to absorb exogenous cellulase added to the culture medium and also retain self-produced cellulase within the biofilm matrix. The bacteria that produced more biofilm degraded more cellulose compared to strains that produced less biofilm. Knockout strains that lacked both EPS and TasA formed a smaller amount of submerged biofilm on cellulose than the wild-type strain and also degraded less cellulose. Imaging of biofilm on cellulose suggests that bacteria, cellulose, and cellulases form cellulolytic biofilm complexes that facilitate synergistic cellulose degradation. This study brings additional insight into the important functions of biofilm in cellulose degradation and could potentiate the development of biofilm-based technology to enhance biomass degradation for biofuel production.
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Hughes JM, Eberl HJ, Sonner S. A mathematical model of discrete attachment to a cellulolytic biofilm using random DEs. MATHEMATICAL BIOSCIENCES AND ENGINEERING : MBE 2022; 19:6582-6619. [PMID: 35730273 DOI: 10.3934/mbe.2022310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
We propose a new mathematical framework for the addition of stochastic attachment to biofilm models, via the use of random ordinary differential equations. We focus our approach on a spatially explicit model of cellulolytic biofilm growth and formation that comprises a PDE-ODE coupled system to describe the biomass and carbon respectively. The model equations are discretized in space using a standard finite volume method. We introduce discrete attachment events into the discretized model via an impulse function with a standard stochastic process as input. We solve our model with an implicit ODE solver. We provide basic simulations to investigate the qualitative features of our model. We then perform a grid refinement study to investigate the spatial convergence of our model. We investigate model behaviour while varying key attachment parameters. Lastly, we use our attachment model to provide evidence for a stable travelling wave solution to the original PDE-ODE coupled system.
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Affiliation(s)
- Jack M Hughes
- Department of Mathematics, University of British Columbia, 1984 Mathematics Rd., Vancouver, BC V6T 1Z2, Canada
| | - Hermann J Eberl
- Department of Mathematics and Statistics, University of Guelph, 50 Stone Rd E., Guelph, ON N1G 2W1, Canada
| | - Stefanie Sonner
- Radboud University, IMAPP - Mathematics, Postbus 9010, 6500 GL Nijmegen, The Netherlands
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4
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Stone W, Louw TM, Booysen MJ, Wolfaardt GM. Canary in the coliform mine: Exploring the industrial application limits of a microbial respiration alarm system. PLoS One 2021; 16:e0247910. [PMID: 33661997 PMCID: PMC7932117 DOI: 10.1371/journal.pone.0247910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 02/16/2021] [Indexed: 11/18/2022] Open
Abstract
Fundamental ecological principles of ecosystem-level respiration are extensively applied in greenhouse gas and elemental cycle studies. A laboratory system termed CEMS (Carbon Dioxide Evolution Measurement System), developed to explore microbial biofilm growth and metabolic responses, was evaluated as an early-warning system for microbial disturbances in industrial settings: in (a) potable water system contamination, and (b) bioreactor inhibition. Respiration was detected as CO2 production, rather than O2 consumption, including aerobic and anaerobic metabolism. Design, thresholds, and benefits of the remote CO2 monitoring technology were described. Headspace CO2 correlated with contamination levels, as well as chemical (R2 > 0.83-0.96) and microbiological water quality indicators (R2 > 0.78-0.88). Detection thresholds were limiting factors in monitoring drinking water to national and international standards (0 CFU/100 mL fecal coliforms) in both open- (>1500 CFU/mL) and closed-loop CO2 measuring regimes (>100 CFU/100 mL). However, closed-loop detection thresholds allow for the detection of significant contamination events, and monitoring less stringent systems such as irrigation water (<100 CFU/mL). Whole-system respiration was effectively harnessed as an early-warning system in bioreactor performance monitoring. Models were used to deconvolute biological CO2 fluctuations from chemical CO2 dynamics, to optimize this real-time, sustainable, low-waste technology, facilitating timeous responses to biological disturbances in bioreactors.
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Affiliation(s)
- Wendy Stone
- Water Institute and Department of Microbiology, Stellenbosch University, Stellenbosch, South Africa
- * E-mail:
| | - Tobi M. Louw
- Department of Process Engineering, Stellenbosch University, Stellenbosch, South Africa
| | - Marthinus J. Booysen
- Department of E&E Engineering, Stellenbosch University, Stellenbosch, South Africa
| | - Gideon M. Wolfaardt
- Water Institute and Department of Microbiology, Stellenbosch University, Stellenbosch, South Africa
- Department of Chemistry and Biology, Ryerson University, Toronto, Canada
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5
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Jiang Y, Liu Y, Zhang X, Gao H, Mou L, Wu M, Zhang W, Xin F, Jiang M. Biofilm application in the microbial biochemicals production process. Biotechnol Adv 2021; 48:107724. [PMID: 33640404 DOI: 10.1016/j.biotechadv.2021.107724] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 02/18/2021] [Accepted: 02/21/2021] [Indexed: 11/16/2022]
Abstract
Biofilms can be naturally formed through the attachment of microorganisms on the supporting materials. However, natural biofilms formed in the environment may cause some detrimental effects, such as the equipment contamination and food safety issues et al. On the contrary, biofilms mediated microbial fermentation provides a promising approach for the efficient biochemicals production owing to the properties of self-immobilization, high resistance to toxic reactants and maintenance of long-term cells activity. While few reviews have specifically addressed the biological application of biofilms in the microbial fermentation process. Accordingly, this review will comprehensively summarize the biofilms formation mechanism and potential functions in the microbial fermentation process. Furthermore, the construction strategies for the formation of stable biofilms through synthetic biology technology or the modification of suitable supporting materials will be also discussed. The application of biofilms mediated fermentation will provide an outlook for the biorefinery platform in the future.
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Affiliation(s)
- Yujia Jiang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211800, PR China
| | - Yansong Liu
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211800, PR China
| | - Xiaoyu Zhang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211800, PR China
| | - Hao Gao
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211800, PR China
| | - Lu Mou
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211800, PR China
| | - Mengdi Wu
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211800, PR China
| | - Wenming Zhang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211800, PR China; Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing 211800, PR China.
| | - Fengxue Xin
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211800, PR China; Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing 211800, PR China.
| | - Min Jiang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211800, PR China; Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing 211800, PR China
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Brethauer S, Shahab RL, Studer MH. Impacts of biofilms on the conversion of cellulose. Appl Microbiol Biotechnol 2020; 104:5201-5212. [PMID: 32337627 PMCID: PMC7275028 DOI: 10.1007/s00253-020-10595-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 03/24/2020] [Accepted: 03/31/2020] [Indexed: 12/02/2022]
Abstract
Abstract Lignocellulose is a widely available renewable carbon source and a promising feedstock for the production of various chemicals in biorefineries. However, its recalcitrant nature is a major hurdle that must be overcome to enable economic conversion processes. Deconstruction of lignocellulose is part of the global carbon cycle, and efficient microbial degradation systems have evolved that might serve as models to improve commercial conversion processes. Biofilms—matrix encased, spatially organized clusters of microbial cells and the predominating lifestyle in nature—have been recognized for their essential role in the degradation of cellulose in nature, e.g., in soils or in the digestive tracts of ruminant animals. Cellulolytic biofilms allow for a high concentration of enzymes at the boundary layer between the solid substrate and the liquid phase and the more complete capture of hydrolysis products directly at the hydrolysis site, which is energetically favorable. Furthermore, enhanced expression of genes for carbohydrate active enzymes as a response to the attachment on solid substrate has been demonstrated for cellulolytic aerobic fungi and anerobic bacteria. In natural multispecies biofilms, the vicinity of different microbial species allows the creation of efficient food webs and synergistic interactions thereby, e.g., avoiding the accumulation of inhibiting metabolites. In this review, these topics are discussed and attempts to realize the benefits of biofilms in targeted applications such as the consolidated bioprocessing of lignocellulose are highlighted. Key Points Multispecies biofilms enable efficient lignocellulose destruction in the biosphere. Cellulose degradation by anaerobic bacteria often occurs by monolayered biofilms. Fungal biofilms immobilize enzymes and substrates in an external digestion system. Surface attached cultures typically show higher expression of cellulolytic enzymes.
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Affiliation(s)
- Simone Brethauer
- School of Agricultural, Forest and Food Sciences, Laboratory of Biofuels and Biochemicals, Bern University of Applied Sciences (BFH), 3052, Zollikofen, Switzerland
| | - Robert L Shahab
- School of Agricultural, Forest and Food Sciences, Laboratory of Biofuels and Biochemicals, Bern University of Applied Sciences (BFH), 3052, Zollikofen, Switzerland
| | - Michael H Studer
- School of Agricultural, Forest and Food Sciences, Laboratory of Biofuels and Biochemicals, Bern University of Applied Sciences (BFH), 3052, Zollikofen, Switzerland.
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Sivadon P, Barnier C, Urios L, Grimaud R. Biofilm formation as a microbial strategy to assimilate particulate substrates. ENVIRONMENTAL MICROBIOLOGY REPORTS 2019; 11:749-764. [PMID: 31342619 DOI: 10.1111/1758-2229.12785] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 07/15/2019] [Accepted: 07/21/2019] [Indexed: 06/10/2023]
Abstract
In most ecosystems, a large part of the organic carbon is not solubilized in the water phase. Rather, it occurs as particles made of aggregated hydrophobic and/or polymeric natural or man-made organic compounds. These particulate substrates are degraded by extracellular digestion/solubilization implemented by heterotrophic bacteria that form biofilms on them. Organic particle-degrading biofilms are widespread and have been observed in aquatic and terrestrial natural ecosystems, in polluted and man-driven environments and in the digestive tracts of animals. They have central ecological functions as they are major players in carbon recycling and pollution removal. The aim of this review is to highlight bacterial adhesion and biofilm formation as central mechanisms to exploit the nutritive potential of organic particles. It focuses on the mechanisms that allow access and assimilation of non-dissolved organic carbon, and considers the advantage provided by biofilms for gaining a net benefit from feeding on particulate substrates. Cooperative and competitive interactions taking place in biofilms feeding on particulate substrates are also discussed.
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Affiliation(s)
- Pierre Sivadon
- CNRS/Université de Pau et des Pays de l'Adour/E2S UPPA, Institut des Sciences Analytiques et de Physico-Chimie pour l'Environnement et les Matériaux UMR5254, Pau, 64000, France
| | - Claudie Barnier
- CNRS/Université de Pau et des Pays de l'Adour/E2S UPPA, Institut des Sciences Analytiques et de Physico-Chimie pour l'Environnement et les Matériaux UMR5254, Pau, 64000, France
| | - Laurent Urios
- CNRS/Université de Pau et des Pays de l'Adour/E2S UPPA, Institut des Sciences Analytiques et de Physico-Chimie pour l'Environnement et les Matériaux UMR5254, Pau, 64000, France
| | - Régis Grimaud
- CNRS/Université de Pau et des Pays de l'Adour/E2S UPPA, Institut des Sciences Analytiques et de Physico-Chimie pour l'Environnement et les Matériaux UMR5254, Pau, 64000, France
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8
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Whitham JM, Moon JW, Rodriguez M, Engle NL, Klingeman DM, Rydzak T, Abel MM, Tschaplinski TJ, Guss AM, Brown SD. Clostridium thermocellum LL1210 pH homeostasis mechanisms informed by transcriptomics and metabolomics. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:98. [PMID: 29632556 PMCID: PMC5887222 DOI: 10.1186/s13068-018-1095-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2017] [Accepted: 03/24/2018] [Indexed: 05/21/2023]
Abstract
BACKGROUND Clostridium (Ruminiclostridium) thermocellum is a model fermentative anaerobic thermophile being studied and engineered for consolidated bioprocessing of lignocellulosic feedstocks into fuels and chemicals. Engineering efforts have resulted in significant improvements in ethanol yields and titers although further advances are required to make the bacterium industry-ready. For instance, fermentations at lower pH could enable co-culturing with microbes that have lower pH optima, augment productivity, and reduce buffering cost. C. thermocellum is typically grown at neutral pH, and little is known about its pH limits or pH homeostasis mechanisms. To better understand C. thermocellum pH homeostasis we grew strain LL1210 (C. thermocellum DSM1313 Δhpt ΔhydG Δldh Δpfl Δpta-ack), currently the highest ethanol producing strain of C. thermocellum, at different pH values in chemostat culture and applied systems biology tools. RESULTS Clostridium thermocellum LL1210 was found to be growth-limited below pH 6.24 at a dilution rate of 0.1 h-1. F1F0-ATPase gene expression was upregulated while many ATP-utilizing enzymes and pathways were downregulated at pH 6.24. These included most flagella biosynthesis genes, genes for chemotaxis, and other motility-related genes (> 50) as well as sulfate transport and reduction, nitrate transport and nitrogen fixation, and fatty acid biosynthesis genes. Clustering and enrichment of differentially expressed genes at pH values 6.48, pH 6.24 and pH 6.12 (washout conditions) compared to pH 6.98 showed inverse differential expression patterns between the F1F0-ATPase and genes for other ATP-utilizing enzymes. At and below pH 6.24, amino acids including glutamate and valine; long-chain fatty acids, their iso-counterparts and glycerol conjugates; glycolysis intermediates 3-phosphoglycerate, glucose 6-phosphate, and glucose accumulated intracellularly. Glutamate was 267 times more abundant in cells at pH 6.24 compared to pH 6.98, and intercellular concentration reached 1.8 μmol/g pellet at pH 5.80 (stopped flow). CONCLUSIONS Clostridium thermocellum LL1210 can grow under slightly acidic conditions, similar to limits reported for other strains. This foundational study provides a detailed characterization of a relatively acid-intolerant bacterium and provides genetic targets for strain improvement. Future studies should examine adding gene functions used by more acid-tolerant bacteria for improved pH homeostasis at acidic pH values.
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Affiliation(s)
- Jason M. Whitham
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN USA
- BioEnergy Science Center, National Laboratory, Oak Ridge, TN USA
| | - Ji-Won Moon
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN USA
| | - Miguel Rodriguez
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN USA
- BioEnergy Science Center, National Laboratory, Oak Ridge, TN USA
| | - Nancy L. Engle
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN USA
- BioEnergy Science Center, National Laboratory, Oak Ridge, TN USA
| | - Dawn M. Klingeman
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN USA
- BioEnergy Science Center, National Laboratory, Oak Ridge, TN USA
| | - Thomas Rydzak
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN USA
- BioEnergy Science Center, National Laboratory, Oak Ridge, TN USA
- Present Address: Department of Biological Science, University of Calgary, Calgary, AB T2N 1N4 Canada
| | - Malaney M. Abel
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN USA
- BioEnergy Science Center, National Laboratory, Oak Ridge, TN USA
| | - Timothy J. Tschaplinski
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN USA
- BioEnergy Science Center, National Laboratory, Oak Ridge, TN USA
| | - Adam M. Guss
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN USA
- BioEnergy Science Center, National Laboratory, Oak Ridge, TN USA
| | - Steven D. Brown
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN USA
- BioEnergy Science Center, National Laboratory, Oak Ridge, TN USA
- Present Address: LanzaTech, Inc., Skokie, IL USA
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Eberl H, Jalbert E, Dumitrache A, Wolfaardt G. A spatially explicit model of inverse colony formation of cellulolytic biofilms. Biochem Eng J 2017. [DOI: 10.1016/j.bej.2017.03.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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10
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Dumitrache A, Klingeman DM, Natzke J, Rodriguez M, Giannone RJ, Hettich RL, Davison BH, Brown SD. Specialized activities and expression differences for Clostridium thermocellum biofilm and planktonic cells. Sci Rep 2017; 7:43583. [PMID: 28240279 PMCID: PMC5327387 DOI: 10.1038/srep43583] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 01/25/2017] [Indexed: 01/01/2023] Open
Abstract
Clostridium (Ruminiclostridium) thermocellum is a model organism for its ability to deconstruct plant biomass and convert the cellulose into ethanol. The bacterium forms biofilms adherent to lignocellulosic feedstocks in a continuous cell-monolayer in order to efficiently break down and uptake cellulose hydrolysates. We developed a novel bioreactor design to generate separate sessile and planktonic cell populations for omics studies. Sessile cells had significantly greater expression of genes involved in catabolism of carbohydrates by glycolysis and pyruvate fermentation, ATP generation by proton gradient, the anabolism of proteins and lipids and cellular functions critical for cell division consistent with substrate replete conditions. Planktonic cells had notably higher gene expression for flagellar motility and chemotaxis, cellulosomal cellulases and anchoring scaffoldins, and a range of stress induced homeostasis mechanisms such as oxidative stress protection by antioxidants and flavoprotein co-factors, methionine repair, Fe-S cluster assembly and repair in redox proteins, cell growth control through tRNA thiolation, recovery of damaged DNA by nucleotide excision repair and removal of terminal proteins by proteases. This study demonstrates that microbial attachment to cellulose substrate produces widespread gene expression changes for critical functions of this organism and provides physiological insights for two cells populations relevant for engineering of industrially-ready phenotypes.
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Affiliation(s)
- Alexandru Dumitrache
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN, 37831, U.S.A.,Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, U.S.A
| | - Dawn M Klingeman
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN, 37831, U.S.A.,Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, U.S.A
| | - Jace Natzke
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN, 37831, U.S.A.,Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, U.S.A
| | - Miguel Rodriguez
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN, 37831, U.S.A.,Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, U.S.A
| | - Richard J Giannone
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN, 37831, U.S.A.,Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, U.S.A
| | - Robert L Hettich
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN, 37831, U.S.A.,Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, U.S.A
| | - Brian H Davison
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN, 37831, U.S.A.,Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, U.S.A
| | - Steven D Brown
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN, 37831, U.S.A.,Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, U.S.A
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11
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Ronan E, Edjiu N, Kroukamp O, Wolfaardt G, Karshafian R. USMB-induced synergistic enhancement of aminoglycoside antibiotics in biofilms. ULTRASONICS 2016; 69:182-190. [PMID: 27111871 DOI: 10.1016/j.ultras.2016.03.017] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 03/08/2016] [Accepted: 03/28/2016] [Indexed: 06/05/2023]
Abstract
This study evaluated the effect of combining antibiotics with ultrasound and microbubbles (USMB) toward the eradication of biofilms. Pseudomonas aeruginosa PAO1 biofilms were treated with the antibiotics gentamicin sulfate or streptomycin sulfate, or a combination of USMB with the respective antibiotics. Biofilm structure was quantified using confocal laser scanning microscopy with COMSTAT analysis, while activity was measured as whole-biofilm CO2 production in a continuous-flow biofilm model. The combined antibiotic-USMB treatment significantly impacted biofilm biomass, thickness and surface roughness compared to antibiotics alone (p<0.05). USMB exposure caused the formation of craters (5-20μm in diameter) in the biofilms, and when combined with gentamicin, activity was significantly lower, compared to gentamicin, USMB or untreated controls, respectively. Interestingly, the CO2 production rate following combined streptomycin-USMB treatment was higher than after streptomycin alone, but significantly lower than USMB alone and untreated control. These results show strong evidence of a synergistic effect between antibiotics and USMB, although the varied response to different antibiotics emphasize the need to optimize the USMB exposure conditions to maximize this synergism and ultimately transfer this technology into clinical or industrial practice.
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Affiliation(s)
- Evan Ronan
- Department of Chemistry and Biology, Ryerson University, Toronto, Ontario, Canada
| | - Narbeh Edjiu
- Department of Physics, Ryerson University, Toronto, Ontario, Canada
| | - Otini Kroukamp
- Department of Chemistry and Biology, Ryerson University, Toronto, Ontario, Canada
| | - Gideon Wolfaardt
- Department of Chemistry and Biology, Ryerson University, Toronto, Ontario, Canada
| | - Raffi Karshafian
- Department of Physics, Ryerson University, Toronto, Ontario, Canada.
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12
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Dumitrache A, Eberl HJ, Allen DG, Wolfaardt GM. Mathematical modeling to validate on-line CO2 measurements as a metric for cellulolytic biofilm activity in continuous-flow bioreactors. Biochem Eng J 2015. [DOI: 10.1016/j.bej.2015.04.022] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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13
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Biofilms of Clostridium species. Anaerobe 2014; 30:193-8. [DOI: 10.1016/j.anaerobe.2014.09.010] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Revised: 09/10/2014] [Accepted: 09/14/2014] [Indexed: 12/30/2022]
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14
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Zuroff TR, Gu W, Fore RL, Leschine SB, Curtis WR. Insights into Clostridium phytofermentans biofilm formation: aggregation, microcolony development and the role of extracellular DNA. MICROBIOLOGY-SGM 2014; 160:1134-1143. [PMID: 24625451 DOI: 10.1099/mic.0.078014-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Biofilm formation is a critical component to the lifestyle of many naturally occurring cellulose-degrading microbes. In this work, cellular aggregation and biofilm formation of Clostridium phytofermentans, a cellulolytic anaerobic bacterium, was investigated using a combination of microscopy and analytical techniques. Aggregates included thread-like linkages and a DNA/protein-rich extracellular matrix when grown on soluble cellobiose. Similar dense biofilms formed on the surface of the model cellulosic substrate Whatman no. 1 filter paper. Following initially dispersed attachment, microcolonies of ~500 µm diameter formed on the filter paper after 6 days. Enzymic treatment of both the biofilm and cellular aggregates with DNase and proteinase resulted in significant loss of rigidity, pointing to the key role of extracellular DNA and proteins in the biofilm structure. A high-throughput biofilm assay was adapted for studying potential regulators of biofilm formation. Various media manipulations were shown to greatly impact biofilm formation, including repression in the presence of glucose but not the β(1→4)-linked disaccharide cellobiose, implicating a balance of hydrolytic activity and assimilation to maintain biofilm integrity. Using the microtitre plate biofilm assay, DNase and proteinase dispersed ~60 and 30 % of mature biofilms, respectively, whilst RNase had no impact. This work suggests that Clostridium phytofermentans has evolved a DNA/protein-rich biofilm matrix complementing its cellulolytic nature. These insights add to our current understanding of natural ecosystems as well as strategies for efficient bioprocess design.
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Affiliation(s)
- Trevor R Zuroff
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA 16802, USA
| | - Weimin Gu
- Department of Microbiology, University of Massachusetts, Amherst, MA 01003, USA
| | - Rachel L Fore
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA 16802, USA
| | - Susan B Leschine
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, MA 01003, USA
| | - Wayne R Curtis
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA 16802, USA
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