Characterization of enriched aerotolerant cellulose-degrading communities for biofuels production using differing selection pressures and inoculum sources

2013 ◽  
Vol 59 (10) ◽  
pp. 679-683 ◽  
Author(s):  
Scott Wushke ◽  
David B. Levin ◽  
Nazim Cicek ◽  
Richard Sparling
Keyword(s):  
Consolidated Bioprocessing ◽  
Ethanol Yield ◽  
Cellulose Degradation ◽  
16S Rrna Gene Sequencing ◽  
Rrna Gene ◽  
Strictly Anaerobic ◽  
Cellulolytic Bacteria ◽  
Moderately Thermophilic ◽  
Rotten Wood ◽  
Gradient Gel Electrophoresis

Ethanol production from direct cellulose fermentation has mainly been described as a strictly anaerobic process. The use of air-tolerant organisms or consortia for this process would reduce the need for prereduction of the medium and also permit continuous feed of aerobic feedstock. To this end, moderately thermophilic (60 °C) consortia of fermentative, cellulolytic bacteria were enriched from 3 distinct environments (manure, marsh, and rotten wood) from a farm in southeast Saskatchewan, Canada. Community phenotypic and metabolic profiles were characterized. Selection methods included direct plating under an aerobic atmosphere and repeated passaging; the methods were designed to select for robust, stable aerotolerant cellulose-degrading communities. Several of the isolated communities exhibited an increase in total cellulose degradation and total ethanol yield when compared with a monoculture of Clostridium thermocellum DSMZ 1237. Owing to stringent selection conditions, low diversity enrichments were found, and many appeared to be binary cultures via density gradient gel electrophoresis analysis. On the basis of 16S rRNA gene sequencing, aerobic conditions selected for a mix of organisms highly related to C. thermocellum and Geobacillus species, while anaerobic conditions led to the development of consortia containing strains related to C. thermocellum with strains from either the genus Geobacillus or the genus Thermoanaerobacter. The presence of a Geobacillus-like species appeared to be a prerequisite for aerotolerance of the cellulolytic enrichments, a highly desired phenotype in lignocellulosic consolidated bioprocessing.

scholarly journals Community Structure Analyses of Anodic Biofilms in a Bioelectrochemical System Combined with an Aerobic Reactor

Energies ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3643 ◽  
Author(s):  
Qiaochu Liang ◽  
Takahiro Yamashita ◽  
Norihisa Matsuura ◽  
Ryoko Yamamoto-Ikemoto ◽  
Hiroshi Yokoyama
Keyword(s):  
Coulombic Efficiency ◽  
Oxygen Demand ◽  
16S Rrna Gene Sequencing ◽  
Limited Range ◽  
Aerobic Bacteria ◽  
Rrna Gene ◽  
Strictly Anaerobic ◽  
Bioelectrochemical System ◽  
Aerobic Conditions ◽  
Exoelectrogenic Bacteria

Bioelectrochemical system (BES)-based reactors have a limited range of use, especially in aerobic conditions, because these systems usually produce current from exoelectrogenic bacteria that are strictly anaerobic. However, some mixed cultures of bacteria in aerobic reactors can form surface biofilms that may produce anaerobic conditions suitable for exoelectrogenic bacteria to thrive. In this study, we combined a BES with an aerobic trickling filter (TF) reactor for wastewater treatment and found that the BES-TF setup could produce electricity with a coulombic efficiency of up to 15% from artificial wastewater, even under aerobic conditions. The microbial communities within biofilms formed at the anodes of BES-TF reactors were investigated using high throughput 16S rRNA gene sequencing. Efficiency of reduction in chemical oxygen demand and total nitrogen content of wastewater using this system was >97%. Bacterial community analysis showed that exoelectrogenic bacteria belonging to the genera Geobacter and Desulfuromonas were dominant within the biofilm coating the anode, whereas aerobic bacteria from the family Rhodocyclaceae were abundant on the surface of the biofilm. Based on our observations, we suggest that BES-TF reactors with biofilms containing aerobic bacteria and anaerobic exoelectrogenic bacteria on the anodes can function in aerobic environments.

scholarly journals Simultaneous Cellulose Degradation and Electricity Production by Enterobacter cloacae in a Microbial Fuel Cell

2009 ◽  
Vol 75 (11) ◽  
pp. 3673-3678 ◽  
Author(s):  
Farzaneh Rezaei ◽  
Defeng Xing ◽  
Rachel Wagner ◽  
John M. Regan ◽  
Tom L. Richard ◽  
...  
Keyword(s):  
16S Rrna ◽  
Microbial Fuel Cells ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Cellulose Degradation ◽  
Enterobacter Cloacae ◽  
Community Analysis ◽  
Electricity Production ◽  
Rrna Gene ◽  
16S Rrna Sequence ◽  
Gradient Gel Electrophoresis

ABSTRACT Electricity can be directly generated by bacteria in microbial fuel cells (MFCs) from many different biodegradable substrates. When cellulose is used as the substrate, electricity generation requires a microbial community with both cellulolytic and exoelectrogenic activities. Cellulose degradation with electricity production by a pure culture has not been previously demonstrated without addition of an exogenous mediator. Using a specially designed U-tube MFC, we enriched a consortium of exoelectrogenic bacteria capable of using cellulose as the sole electron donor. After 19 dilution-to-extinction serial transfers of the consortium, 16S rRNA gene-based community analysis using denaturing gradient gel electrophoresis and band sequencing revealed that the dominant bacterium was Enterobacter cloacae. An isolate designated E. cloacae FR from the enrichment was found to be 100% identical to E. cloacae ATCC 13047T based on a partial 16S rRNA sequence. In polarization tests using the U-tube MFC and cellulose as a substrate, strain FR produced 4.9 ± 0.01 mW/m2, compared to 5.4 ± 0.3 mW/m2 for strain ATCC 13047T. These results demonstrate for the first time that it is possible to generate electricity from cellulose using a single bacterial strain without exogenous mediators.

scholarly journals Desulfocarbo indianensis gen. nov., sp. nov., a benzoate-oxidizing, sulfate-reducing bacterium isolated from water extracted from a coal bed

2014 ◽  
Vol 64 (Pt_8) ◽  
pp. 2907-2914 ◽  
Author(s):  
Thuy T. An ◽  
Flynn W. Picardal
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
16S Rrna Gene Sequencing ◽  
Optimal Growth ◽  
Coal Bed ◽  
Rrna Gene ◽  
Strictly Anaerobic ◽  
Content Type ◽  
Sulfate Reducing ◽  
Link Type

A novel, strictly anaerobic, sulfate-reducing bacterium, designated strain SCBMT, was isolated from water extracted from a coal bed in Indiana, USA. The isolate was characterized by a polyphasic taxonomic approach that included phenotypic and genotypic characterizations. Cells of strain SCBMT were vibrio-shaped, polarly flagellated, Gram-negative, motile, oxidase-negative and weakly catalase-positive. Growth of strain SCBMT was observed at NaCl concentrations ranging from 0 to 300 mM. However, no growth was observed when 1 M or more NaCl was present. Growth was observed at 16–37 °C, with optimal growth at 30 °C. The optimum pH for growth was 7, although growth was observed from pH 6.5 to 8. The doubling time under optimal growth conditions (30 °C, pH 7, 2.5 mM benzoate, 14 mM sulfate) was 2.7 days. Bicarbonate, HEPES, PIPES and MES were effective buffers for growth of strain SCBMT, but citrate inhibited growth. When sulfate was provided as the electron acceptor, strain SCBMT grew autotrophically with hydrogen as the electron donor and heterotrophically on benzoate, formate, acetate, pyruvate, butyrate, fumarate, succinate and palmitate. None of the substrates tested supported fermentative growth. Thiosulfate and sulfate were used as electron acceptors coupled to benzoate oxidation, but sulfite, elemental sulfur, DMSO, anthraquinone 2,6-disulfonate, nitrate, nitrite, ferric citrate, hydrous iron oxide and oxygen were not. The G+C content of genomic DNA was 62.5 mol%. The major cellular fatty acids were anteiso-C15 : 0 and C18 : 1ω7c. Phylogenetic analysis based on 16S rRNA gene sequencing placed strain SCBMT into a distinct lineage within the class Deltaproteobacteria . The closest, cultivated phylogenetic relative of strain SCBMT was Desulfarculus baarsii DSM 2075T, with only 91.7 % 16S rRNA gene sequence identity. On the basis of phenotypic and genotypic analyses, strain SCBMT represents a novel genus and species of sulfate-reducing bacteria, for which the name Desulfocarbo indianensis gen. nov., sp. nov. is proposed. The type strain of Desulfocarbo indianensis is SCBMT ( = DSM 28127T = JCM 19826T). Desulfocarbo is the second genus of the order Desulfarculales .

Thermophagus xiamenensis gen. nov., sp. nov., a moderately thermophilic and strictly anaerobic bacterium isolated from hot spring sediment

2013 ◽  
Vol 63 (Pt_1) ◽  
pp. 109-113 ◽  
Author(s):  
Zhao-Ming Gao ◽  
Xin Liu ◽  
Xi-Ying Zhang ◽  
Ling-Wei Ruan
Keyword(s):  
16S Rrna ◽  
Type Species ◽  
Anaerobic Bacterium ◽  
Hot Spring ◽  
Rrna Gene ◽  
Strictly Anaerobic ◽  
Content Type ◽  
Moderately Thermophilic ◽  
Link Type ◽  
The Family

A moderately thermophilic and strictly anaerobic bacterium, designated HS1T, was isolated from offshore hot spring sediment in Xiamen, China. Cells were Gram-negative, catalase-positive, oxidase-negative, slender and flexible rods without flagella. The strain could grow at 35–55 °C (optimum at 50 °C) and in 1–8 % NaCl (w/v; optimum 2–4 %). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain HS1T was affiliated with the family Marinilabiliaceae and shared a distant relationship with the previously described genera. The isolate was most closely related to Anaerophaga thermohalophila Fru22T with 16S rRNA gene sequence similarity of 92.4 %, followed by the other members of the family Marinilabiliaceae with 88.7–91.1 % similarity. The dominant cellular fatty acids were iso-C15 : 0 and anteiso-C15 : 0. The predominant quinone was MK-7. The major polar lipids were phosphatidylethanolamine (PE) and an unknown polar lipid. The genomic DNA G+C content was 38.7 mol%. Besides the phylogenetically distant relationship, strain HS1T was obviously distinguished from the most closely related genera in several phenotypic properties including colony colour and pigment production, optimal temperature, optimal NaCl, relation to O2, bicarbonate/carbonate requirement, catalase activity, nitrate reduction, fermentation products and cellular fatty acid profile. Based on the phenotypic and phylogenetic data, strain HS1T represents a novel species of a new genus, for which the name Thermophagus xiamenensis gen. nov., sp. nov. is proposed. The type strain of the type species is HS1T ( = DSM 19012T = CGMCCC 1.5071T).

Fonticella tunisiensis gen. nov., sp. nov., isolated from a hot spring

2013 ◽  
Vol 63 (Pt_6) ◽  
pp. 1947-1950 ◽  
Author(s):  
Belkis Fraj ◽  
Wajdi Ben Hania ◽  
Anne Postec ◽  
Moktar Hamdi ◽  
Bernard Ollivier ◽  
...  
Keyword(s):  
Type Species ◽  
Hot Spring ◽  
Sequence Similarity ◽  
Rrna Gene ◽  
Strictly Anaerobic ◽  
Fermentation Products ◽  
Content Type ◽  
Moderately Thermophilic ◽  
Link Type ◽  
Nitrate And Nitrite

A strictly anaerobic, moderately thermophilic, halotolerant rod, designated BELH25T, was isolated from a water sample of a Tunisian hot spring. Cells were non-motile, 2–6 µm long and 0.4–0.6 µm wide, appearing singly or in pairs. The isolate grew at 45–70 °C (optimum 55 °C), at pH 6.2–8.0 (optimum pH 7.0) and with 0–4 % NaCl (optimum 0–2.0 %). Sulfate, thiosulfate, elemental sulfur, sulfite, nitrate and nitrite were not used as terminal electron acceptors. Strain BELH25T used cellobiose, fructose, galactose, glucose, maltose, mannose, sucrose, starch and yeast extract as electron donors. The main fermentation products from glucose metabolism were formate, acetate, ethanol and CO2. The predominant cellular fatty acids were iso-C15 : 0, iso-C17 : 0 and anteiso-C15 : 0. The DNA G+C content was 37.2 mol%. Phylogenetic analysis of the 16S rRNA gene sequence indicated that strain BELH25T was most closely related to Caloramator viterbiensis JW/MS-VS5T and Fervidicella metallireducens AeBT (92.2 and 92.1 % sequence similarity, respectively), and the isolate was positioned approximately equidistantly between these genera. Based on phenotypic, phylogenetic and chemotaxonomic characteristics, strain BELH25T is proposed to be a member of a novel species of a novel genus within the order Clostridiales , family Clostridiaceae , for which the name Fonticella tunisiensis gen. nov., sp. nov. is proposed. The type strain of the type species is BELH25T ( = DSM 24455T = JCM 17559T).

scholarly journals Screening of Cellulolytic Bacteria from Rotten Wood of Qinling (China) for Biomass Degradation and Cloning of Cellulases from Bacillus methylotrophicus

2019 ◽  
Author(s):  
Lingling Ma ◽  
Yingying Lu ◽  
Hong Yan ◽  
Xin Wang ◽  
Yanglei Yi ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Wheat Straw ◽  
Cellulose Degradation ◽  
Good Effect ◽  
Qinling Mountains ◽  
Cellulolytic Bacteria ◽  
Biomass Degradation ◽  
Bacillus Methylotrophicus ◽  
Rotten Wood ◽  
Degradation Effect

Abstract Background Cellulosic biomass degradation still needs to be paid more attentions as bioenergy is the most likely to replace fossil energy in the future, and more evaluable cellulolytic bacteria isolation will lay a foundation for this filed. Qinling Mountains have unique biodiversity, acting as promising source of cellulose-degrading bacteria exhibiting noteworthy properties. Therefore, the aim of this work was to find potential cellulolytic bacteria and verify the possibility of the cloning of cellulases from the selected powerful bacteria. Results In present study, 55 potential cellulolytic bacteria were screened and identified from the rotten wood of Qinling Mountains. Based on the investigation of cellulase activities and degradation effect on different cellulose substrates, Bacillus methylotrophicus 1EJ7, Bacillus subtilis 1AJ3 and Bacillus subtilis 3BJ4 were further applied to hydrolyze wheat straw, corn stover and switchgrass, and the results suggested that B. methylotrophicus 1EJ7 was the most preponderant bacterium, and which also indicated that Bacillus was the main cellulolytic bacteria in rotten wood. Furthermore, scanning electron microscopy (SEM) and X-ray diffraction analysis of micromorphology and crystallinity of wheat straw also verified the significant hydrolyzation. With ascertaining the target sequence of cellulase β-glucosidase (243 aa) and endoglucanase (499 aa) were successfully heterogeneously cloned and expressed from B. methylotrophicus 1EJ7, and which performed a good effect on cellulose degradation with enzyme activity of 1670.15±18.94 U/mL and 0.130±0.002 U/mL, respectively. In addition, based on analysis of amino acid sequence, it found that β-glucosidase were belonged to GH16 family, and endoglucanase was composed of GH5 family catalytic domain and a carbohydrate-binding module of CBM3 family. Conclusions Based on the screening, identification and cellulose degradation effect evaluation of cellulolytic bacteria from rotten wood of Qinling Mountains, it found that Bacillus were the predominant species among the isolated strains, and B. methylotrophicus 1EJ7 performed best on cellulose degradation. Meanwhile, the β-glucosidase and endoglucanase were successfully cloned and expressed from B. methylotrophicus for the first time, which provided new materials of both strain and the recombinant enzymes for the study of cellulose degradation and its application in industry.

scholarly journals Clostridium straminisolvens sp. nov., a moderately thermophilic, aerotolerant and cellulolytic bacterium isolated from a cellulose-degrading bacterial community

2004 ◽  
Vol 54 (6) ◽  
pp. 2043-2047 ◽  
Author(s):  
Souichiro Kato ◽  
Shin Haruta ◽  
Zong Jun Cui ◽  
Masaharu Ishii ◽  
Akira Yokota ◽  
...  
Keyword(s):  
Bacterial Community ◽  
Gene Sequence ◽  
Cellulose Degradation ◽  
Sequence Similarity ◽  
Rrna Gene ◽  
Cellulolytic Bacterium ◽  
Moderately Thermophilic ◽  
Initial Ph ◽  
Bacterium Strain ◽  
Curved Rod

A novel anaerobic, thermophilic and cellulolytic bacterium (strain CSK1T) was isolated from a cellulose-degrading bacterial community. On the basis of 16S rRNA gene sequence similarity, strain CSK1T was mapped to cluster III of the genus Clostridium. Strain CSK1T is closely related to Clostridium thermocellum (96·2 %) and Clostridium aldrichii (95·1 %). Strain CSK1T is a non-motile, spore-forming, straight or slightly curved rod. The optimum temperature and initial pH for its growth and cellulose degradation are 50–55 °C and pH 7·5. Strain CSK1T grew under a gas phase containing up to 4 % O2. Phylogenetic and phenotypic analyses support the differentiation of strain CSK1T from its closest relatives. Strain CSK1T therefore represents a novel species, for which the name Clostridium straminisolvens sp. nov. is proposed, with CSK1T (=DSM 16021T=IAM 15070T) as the type strain.

scholarly journals Anaerobic and Aerobic Degradation of Cyanophycin by the Denitrifying Bacterium Pseudomonas alcaligenes Strain DIP1 and Role of Three Other Coisolates in a Mixed Bacterial Consortium

2008 ◽  
Vol 74 (11) ◽  
pp. 3434-3443 ◽  
Author(s):  
Ahmed Sallam ◽  
Alexander Steinbüchel
Keyword(s):  
High Performance ◽  
Physiological Role ◽  
16S Rrna Gene Sequencing ◽  
Rrna Gene ◽  
Strictly Anaerobic ◽  
Bacterial Strains ◽  
Direct Role ◽  
Aerobic Conditions ◽  
Pseudomonas Alcaligenes

ABSTRACT Four bacterial strains were isolated from a cyanophycin granule polypeptide (CGP)-degrading anaerobic consortium, identified by 16S rRNA gene sequencing, and assigned to species of the genera Pseudomonas, Enterococcus, Clostridium, and Paenibacillus. The consortium member responsible for CGP degradation was assigned as Pseudomonas alcaligenes strain DIP1. The growth of and CGP degradation by strain DIP1 under anaerobic conditions were enhanced but not dependent on the presence of nitrate as an electron acceptor. CGP was hydrolyzed to its constituting β-Asp-Arg dipeptides, which were then completely utilized within 25 and 4 days under anaerobic and aerobic conditions, respectively. The end products of CGP degradation by strain DIP1 were alanine, succinate, and ornithine as determined by high-performance liquid chromatography analysis. The facultative anaerobic Enterococcus casseliflavus strain ELS3 and the strictly anaerobic Clostridium sulfidogenes strain SGB2 were coisolates and utilized the β-linked isodipeptides from the common pool available to the mixed consortium, while the fourth isolate, Paenibacillus odorifer strain PNF4, did not play a direct role in the biodegradation of CGP. Several syntrophic interactions affecting CGP degradation, such as substrate utilization, the reduction of electron acceptors, and aeration, were elucidated. This study demonstrates the first investigation of CGP degradation under both anaerobic and aerobic conditions by one bacterial strain, with regard to the physiological role of other bacteria in a mixed consortium.

Methanoculleus horonobensis sp. nov., a methanogenic archaeon isolated from a deep diatomaceous shale formation

2013 ◽  
Vol 63 (Pt_11) ◽  
pp. 4320-4323 ◽  
Author(s):  
Satoru Shimizu ◽  
Akio Ueno ◽  
Shuji Tamamura ◽  
Takeshi Naganuma ◽  
Katsuhiko Kaneko
Keyword(s):  
Sequence Similarity ◽  
16S Rrna Gene Sequencing ◽  
Rrna Gene ◽  
Strictly Anaerobic ◽  
Content Type ◽  
Link Type ◽  
Optimum Ph ◽  
Shale Formation ◽  
Rrna Gene Sequencing ◽  
Type Strains

A methanogenic organism from the domain Archaea , designated strain T10T, was isolated from groundwater sampled from a deep diatomaceous shale formation located in Horonobe, Hokkaido, Japan. The strain utilized H2/CO2 and formate as substrates for methanogenesis. Cells were strictly anaerobic, Gram-negative-staining, flagellated, irregular coccoids, 0.7–1.6 µm in diameter, and occurred singly. The strain grew at 25–45 °C (optimum 37–42 °C), at pH 5.8–8.2 (optimum pH 6.7–6.8) and in the presence of 0–1.3 M NaCl (optimum 0.1–0.2 M NaCl). The G+C content of the genomic DNA was 62.9 mol%. 16S rRNA gene sequencing revealed that, although the strain is a member of the genus Methanoculleus , it clearly differed from all described species of this genus (95.5–98.3 % sequence similarity). Values for DNA–DNA hybridization with type strains of closely related Methanoculleus species were less than 50 %. Phenotypic and phylogenetic features of strain T10T clearly indicate that it represents a novel species of the genus Methanoculleus , for which the name Methanoculleus horonobensis sp. nov. is proposed. The type strain is T10T ( = DSM 21626T = JCM 15517T).

scholarly journals Slackia faecicanis sp. nov., isolated from canine faeces

2005 ◽  
Vol 55 (3) ◽  
pp. 1243-1246 ◽  
Author(s):  
Paul A. Lawson ◽  
Hazel L. Greetham ◽  
Glenn R. Gibson ◽  
Catriona Giffard ◽  
Enevold Falsen ◽  
...  
Keyword(s):  
Novel Species ◽  
Molecular Genetic ◽  
Gene Sequencing ◽  
16S Rrna Gene Sequencing ◽  
Rrna Gene ◽  
Strictly Anaerobic ◽  
Anaerobic Conditions ◽  
Genetic Studies ◽  
The Family ◽  
Rrna Gene Sequencing

Morphological, biochemical and molecular genetic studies were carried out on an unknown non-spore-forming, Gram-positive, rod-shaped bacterium that was isolated from dog faeces. The bacterium grew under strictly anaerobic conditions, was asaccharolytic, and possessed a relatively high G+C content of 61 mol%. Phylogenetic analysis based on comparative 16S rRNA gene sequencing showed that the unidentified bacterium was a member of the family Coriobacteriaceae and represents a hitherto unknown subline within the genus Slackia. Based on the presented findings, a novel species, Slackia faecicanis sp. nov., is described. The type strain of Slackia faecicanis is 5WC12T (=CCUG 48399T=CIP 108281T).

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