| clostridium ljungdahlii sp. nov., an acetogenic species in clostridial rrna homology group i. | clostridium ljungdahlii sp. nov. strain atcc 49587t (t = type strain) was isolated from chicken yard waste for its ability to produce ethanol from synthesis gas. this gram-positive, motile, sporeforming rod's metabolism was primarily acetogenic. c. ljungdahlii grew with carbon monoxide, hydrogen and carbon dioxide, ethanol, pyruvate, arabinose, xylose, fructose, or glucose. methanol, ferulic acid, lactate, galactose, and mannose did not support growth. the g+c content was 22 to 23 mol%. c. ljung ... | 1993 | 7684239 |
| development and comparisons of efficient gas-cultivation systems for anaerobic carbon monoxide-utilizing microorganisms. | we describe a system for the cultivation of gaseous substrate utilizing microorganisms that overcomes some of the limitations of fixed volume culture vessels and the costs associated with sparging. cali-5-bond gas-sampling bag was used as the culture vessel. the bags contain approximately six times more mass of co than the 40 ml vials at 1 atm of pressure and performed equally to the 40 ml vials in terms of their ability to maintain the composition of the gas over extended incubation times. expe ... | 2008 | 17337181 |
| ethanol and acetate production by clostridium ljungdahlii and clostridium autoethanogenum using resting cells. | combined gasification and fermentation technologies can potentially produce biofuels from renewable biomass. gasification generates synthesis gas consisting primarily of co, co(2), h(2), n(2), with smaller amounts of ch(4), no(x), o(2), c(2) compounds, ash and tars. several anaerobic bacteria species can ferment bottled mixtures of pure synthesis gas constituents. however, there are challenges to maintaining culture viability of synthesis gas exposed cells. this study was designed to enhance cul ... | 2009 | 18726618 |
| biomass-derived syngas fermentation into biofuels: opportunities and challenges. | the conversion of biomass-derived synthesis gas (or syngas in brief) into biofuels by microbial catalysts (such as clostridium ljungdahlii, clostridium autoethanogenum, acetobacterium woodii, clostridium carboxidivorans and peptostreptococcus productus) has gained considerable attention as a promising alternative for biofuel production in the recent past. the utilization of the whole biomass, including lignin, irrespective of biomass quality, the elimination of complex pre-treatment steps and co ... | 2010 | 20096574 |
| clostridium ljungdahlii represents a microbial production platform based on syngas. | clostridium ljungdahlii is an anaerobic homoacetogen, able to ferment sugars, other organic compounds, or co(2)/h(2) and synthesis gas (co/h(2)). the latter feature makes it an interesting microbe for the biotech industry, as important bulk chemicals and proteins can be produced at the expense of co(2), thus combining industrial needs with sustained reduction of co and co(2) in the atmosphere. sequencing the complete genome of c. ljungdahlii revealed that it comprises 4,630,065 bp and is one of ... | 2010 | 20616070 |
| electrosynthesis of organic compounds from carbon dioxide is catalyzed by a diversity of acetogenic microorganisms. | microbial electrosynthesis, a process in which microorganisms use electrons derived from electrodes to reduce carbon dioxide to multicarbon, extracellular organic compounds, is a potential strategy for capturing electrical energy in carbon-carbon bonds of readily stored and easily distributed products, such as transportation fuels. to date, only one organism, the acetogen sporomusa ovata, has been shown to be capable of electrosynthesis. the purpose of this study was to determine if a wider rang ... | 2011 | 21378039 |
| microbial production of ethanol from carbon monoxide. | production of ethanol from fermentation of co has received much attention in the last few years with several companies proposing to use co fermentation in their ethanol production processes. the genomes of two co fermenters, clostridium ljungdahlii and clostridium carboxidivorans, have recently been sequenced. the genetic information obtained from this sequencing is aiding molecular biologists who are enhancing ethanol and butanol production by genetic manipulation. several studies have optimize ... | 2011 | 21470845 |
| genome-guided analysis of physiological and morphological traits of the fermentative acetate oxidizer thermacetogenium phaeum. | thermacetogenium phaeum is a thermophilic strictly anaerobic bacterium oxidizing acetate to co(2) in syntrophic association with a methanogenic partner. it can also grow in pure culture, e.g., by fermentation of methanol to acetate. the key enzymes of homoacetate fermentation (wood-ljungdahl pathway) are used both in acetate oxidation and acetate formation. the obvious reversibility of this pathway in this organism is of specific interest since syntrophic acetate oxidation operates close to the ... | 2012 | 23259483 |
| the rnf complex of clostridium ljungdahlii is a proton-translocating ferredoxin:nad+ oxidoreductase essential for autotrophic growth. | it has been predicted that the rnf complex of clostridium ljungdahlii is a proton-translocating ferredoxin:nad(+) oxidoreductase which contributes to atp synthesis by an h(+)-translocating atpase under both autotrophic and heterotrophic growth conditions. the recent development of methods for genetic manipulation of c. ljungdahlii made it possible to evaluate the possible role of the rnf complex in energy conservation. disruption of the c. ljungdahlii rnf operon inhibited autotrophic growth. atp ... | 2012 | 23269825 |
| metabolic response of clostridium ljungdahlii to oxygen exposure. | clostridium ljungdahlii is an important synthesis gas-fermenting bacterium used in the biofuels industry, and a preliminary investigation showed that it has some tolerance to oxygen when cultured in rich mixotrophic medium. batch cultures not only continue to grow and consume h2, co, and fructose after 8% o2 exposure, but fermentation product analysis revealed an increase in ethanol concentration and decreased acetate concentration compared to non-oxygen-exposed cultures. in this study, the mech ... | 2015 | 26431975 |
| sequential mixed cultures: from syngas to malic acid. | synthesis gas (syngas) fermentation using acetogenic bacteria is an approach for production of bulk chemicals like acetate, ethanol, butanol, or 2,3-butandiol avoiding the fuel vs. food debate by using carbon monoxide, carbon dioxide, and hydrogen from gasification of biomass or industrial waste gases. suffering from energetic limitations, yields of c4-molecules produced by syngas fermentation are quite low compared with abe fermentation using sugars as a substrate. on the other hand, fungal pro ... | 2016 | 27445993 |
| [screening of homoacetogen mixed culture converting h2/co2 to acetate]. | homoacetogens are a group of microorganisms with application potential to produce chemicals and biofuels by the bioconversion of synthesis gas. in this study, we collected waste activated sludge samples to screen homoacetogens by hungate anaerobic technique, and studied the effect of ph on acetate and alcohol production from h2/co2 gas. the mixed culture contained clostridium ljungdahlii, lysinibacillus fusiformis and bacillus cereus. acetate concentration achieved 31.69 mmol/l when the initial ... | 2014 | 26016379 |
| occurrence of ferredoxin:nad(+) oxidoreductase activity and its ion specificity in several gram-positive and gram-negative bacteria. | a ferredoxin:nad(+) oxidoreductase was recently discovered as a redox-driven ion pump in the anaerobic, acetogenic bacterium acetobacterium woodii. the enzyme is assumed to be encoded by the rnf genes. since these genes are present in the genomes of many bacteria, we tested for ferredoxin:nad(+) oxidoreductase activity in cytoplasmic membranes from several different gram-positive and gram-negative bacteria that have annotated rnf genes. we found this activity in clostridium tetanomorphum, clostr ... | 2016 | 26793417 |
| crispr/cas9-based efficient genome editing in clostridium ljungdahlii, an autotrophic gas-fermenting bacterium. | acetogenic bacteria have the potential to convert single carbon gases (co and co2) into a range of bulk chemicals and fuels. realization of their full potential is being impeded by the absence of effective genetic tools for high throughput genome modification. here we report the development of a highly efficient crispr/cas9 system for rapid genome editing of clostridium ljungdahlii, a paradigm for the commercial production of ethanol from synthesis gas. following the experimental selection of tw ... | 2016 | 27276212 |
| a roadmap for gene system development in clostridium. | clostridium species are both heroes and villains. some cause serious human and animal diseases, those present in the gut microbiota generally contribute to health and wellbeing, while others represent useful industrial chassis for the production of chemicals and fuels. to understand, counter or exploit, there is a fundamental requirement for effective systems that may be used for directed or random genome modifications. we have formulated a simple roadmap whereby the necessary gene systems maybe ... | 2016 | 27234263 |
| lactose-inducible system for metabolic engineering of clostridium ljungdahlii. | the development of tools for genetic manipulation of clostridium ljungdahlii has increased its attractiveness as a chassis for autotrophic production of organic commodities and biofuels from syngas and microbial electrosynthesis and established it as a model organism for the study of the basic physiology of acetogenesis. in an attempt to expand the genetic toolbox for c. ljungdahlii, the possibility of adapting a lactose-inducible system for gene expression, previously reported for clostridium p ... | 2014 | 24509933 |
| novel system for efficient isolation of clostridium double-crossover allelic exchange mutants enabling markerless chromosomal gene deletions and dna integration. | isolation of clostridium mutants based on gene replacement via allelic exchange remains a major limitation for this important genus. use of a heterologous counterselection marker can facilitate the identification of the generally rare allelic exchange events. we report on the development of an inducible counterselection marker and describe its utility and broad potential in quickly and efficiently generating markerless dna deletions and integrations at any genomic locus without the need for auxo ... | 2012 | 22983967 |
| characterization of an acetoin reductase/2,3-butanediol dehydrogenase from clostridium ljungdahlii dsm 13528. | acetoin reductase catalyzes the formation of 2,3-butanediol from acetoin. in clostridium ljungdahlii dsm 13528, the gene clju_c23220 encoding the putative zn(2+)-dependent alcohol dehydrogenase was cloned and expressed in escherichia coli. the recombinant enzyme, clar, can catalyze the conversion of acetoin to 2,3-butanediol with nadph as the cofactor. furthermore, the gene clju_c23220 was introduced into clostridium acetobutylicum atcc 824 and the transformant was conferred the capacity of 2,3- ... | 2015 | 26320708 |
| spatiotemporal modeling of microbial metabolism. | microbial systems in which the extracellular environment varies both spatially and temporally are very common in nature and in engineering applications. while the use of genome-scale metabolic reconstructions for steady-state flux balance analysis (fba) and extensions for dynamic fba are common, the development of spatiotemporal metabolic models has received little attention. | 2016 | 26932448 |
| integrating syngas fermentation with the carboxylate platform and yeast fermentation to reduce medium cost and improve biofuel productivity. | to ensure economic implementation of syngas fermentation as a fuel-producing platform, engineers and scientists must both lower operating costs and increase product value. a considerable part of the operating costs is spent to procure chemicals for fermentation medium that can sustain sufficient growth of carboxydotrophic bacteria to convert synthesis gas (syngas: carbon monoxide, hydrogen, and carbon dioxide) into products such as ethanol. recently, we have observed that wildtype carboxydotroph ... | 2013 | 24350452 |
| butanol formation from gaseous substrates. | mostly, butanol is formed as a product by saccharolytic anaerobes, employing the so-called abe fermentation (for acetone-butanol-ethanol). however, this alcohol can also be produced from gaseous substrates such as syn(thesis) gas (major components are carbon monoxide and hydrogen) by autotrophic acetogens. in view of economic considerations, a biotechnological process based on cheap and abundant gases such as co and co2 as a carbon source is preferable to more expensive sugar or starch fermentat ... | 2016 | 26903012 |
| clostridium luticellarii sp. nov., isolated from a mud cellar used for producing strong aromatic liquors. | a strictly anaerobic, gram-stain-positive bacterium, designated fw431t, was isolated from a mud cellar used for producing strong aromatic chinese liquors. the strain was able to produce butanoic acid, an important component of the aroma style of chinese liquors. cells of strain fw431t were straight or slightly curved rods with a polar endospore and peritrichous flagella. the major cellular fatty acids (>10 % of the total) were c16 : 0, c18 : 1ω9c and c18 : 0. biolog assays indicated that the str ... | 2015 | 26420591 |
| uvc-mutagenesis in acetogens: resistance to methanol, ethanol, acetone, or n-butanol in recombinants with tailored genomes as the step in engineering of commercial biocatalysts for continuous co₂/h₂ blend fermentations. | time- and cost-efficient six-step uvc-mutagenesis was developed and validated to generate acetogen mutants with preliminary reduced genomes to prevent product inhibition in the to-be-engineered commercial biocatalysts. genome reduction was performed via elimination of pta, ack, spo0a, spo0j and some pro-phage genes. uvc-mutants such as clostridium sp. mt1784rg, clostridium sp. mt653rg, clostridium sp. mt896rg, and clostridium sp. mt1962rg (all 4 share 97 % dna homology with clostridium ljungdahl ... | 2014 | 24415498 |
| a versatile method for preparation of hydrated microbial-latex biocatalytic coatings for gas absorption and gas evolution. | we describe a latex wet coalescence method for gas-phase immobilization of microorganisms on paper which does not require drying for adhesion. this method reduces drying stresses to the microbes. it is applicable for microorganisms that do not tolerate desiccation stress during latex drying even in the presence of carbohydrates. small surface area, 10-65 μm thick coatings were generated on chromatography paper strips and placed in the head-space of vertical sealed tubes containing liquid to hydr ... | 2012 | 22592947 |
| functional expression of the clostridium ljungdahlii acetyl-coa synthase in clostridium acetobutylicum as demonstrated by a novel in vivo co exchange activity, on the way to heterologous installation of a functional wood-ljungdahl pathway. | engineering the wood-ljungdahl pathway (wlp) in the established industrial organism clostridium acetobutylicum would allow for the conversion of carbohydrates into butanol, acetone, and other metabolites at higher yields than is currently possible, while minimizing co2 and h2 release. to this effect, we expressed 11 c. ljungdahlii core genes coding for enzymes and accessory proteins of the wlp in c. acetobutylicum the engineered wlp in c. acetobutylicum showed functionality of the eastern branch ... | 2018 | 29374033 |
| characterization of two novel butanol dehydrogenases involved in butanol degradation in syngas-utilizing bacterium clostridium ljungdahlii dsm 13528. | syngas utilizing bacterium clostridium ljungdahlii dsm 13528 is a promising platform organism for a whole variety of different biofuels and biochemicals production from syngas. during syngas fermentation, c. ljungdahlii dsm 13528 could convert butanol into butyrate, which significantly reduces productivity of butanol. however, there has been no any enzyme involved in the degradation of butanol characterized in c. ljungdahlii dsm 13528. in this study two genes, clju_c24880 and clju_c39950, encodi ... | 2014 | 23720212 |
| a study of co/syngas bioconversion by clostridium autoethanogenum with a flexible gas-cultivation system. | bioconversion of co/syngas to produce ethanol is a novel route in bioethanol production, which can be accomplished by some acetogens. specific culture vessels and techniques are needed to cultivate these microorganisms since they are anaerobic and substrates are gaseous. in this work, gas-sampling bag was applied as a gas-cultivation system to study co/syngas bioconversion by clostridium autoethanogenum and was demonstrated to be efficient because of its flexibility and excellent ability to main ... | 2017 | 28433187 |
| traits of selected clostridium strains for syngas fermentation to ethanol. | syngas fermentation is an anaerobic bioprocess that could become industrially relevant as a biorefinery platform for sustainable production of fuels and chemicals. an important prerequisite for commercialization is adequate performance of the biocatalyst (i.e., sufficiently high production rate, titer, selectivity, yield, and stability of the fermentation). here, we compared the performance of three potential candidate clostridium strains in syngas-to-ethanol conversion: clostridium ljungdahlii ... | 2016 | 26331212 |
| energy conservation associated with ethanol formation from h2 and co2 in clostridium autoethanogenum involving electron bifurcation. | most acetogens can reduce co2 with h2 to acetic acid via the wood-ljungdahl pathway, in which the atp required for formate activation is regenerated in the acetate kinase reaction. however, a few acetogens, such as clostridium autoethanogenum, clostridium ljungdahlii, and clostridium ragsdalei, also form large amounts of ethanol from co2 and h2. how these anaerobes with a growth ph optimum near 5 conserve energy has remained elusive. we investigated this question by determining the specific acti ... | 2015 | 26148714 |
| comparison of single-molecule sequencing and hybrid approaches for finishing the genome of clostridium autoethanogenum and analysis of crispr systems in industrial relevant clostridia. | clostridium autoethanogenum strain ja1-1 (dsm 10061) is an acetogen capable of fermenting co, co2 and h2 (e.g. from syngas or waste gases) into biofuel ethanol and commodity chemicals such as 2,3-butanediol. a draft genome sequence consisting of 100 contigs has been published. | 2014 | 24655715 |
| impact of formate on the growth and productivity of clostridium ljungdahlii petc and clostridium carboxidivorans p7 grown on syngas. | the current energy model based on fossil fuels is coming to an end due to the increase in global energy demand. biofuels such as ethanol and butanol can be produced through the syngas fermentation by acetogenic bacteria. the present work hypothesizes that formate addition would positively impact kinetic parameters for growth and alcohol production in clostridium ljungdahlii petc and clostridium carboxidivorans p7 by diminishing the need for reducing equivalents. fermentation experiments were con ... | 2014 | 26421736 |
| in situ hydrogen utilization for high fraction acetate production in mixed culture hollow-fiber membrane biofilm reactor. | syngas fermentation is a promising route for resource recovery. acetate is an important industrial chemical product and also an attractive precursor for liquid biofuels production. this study demonstrated high fraction acetate production from syngas (h₂ and co₂) in a hollow-fiber membrane biofilm reactor, in which the hydrogen utilizing efficiency reached 100% during the operational period. the maximum concentration of acetate in batch mode was 12.5 g/l, while the acetate concentration in contin ... | 2013 | 24196583 |
| a narrow ph range supports butanol, hexanol, and octanol production from syngas in a continuous co-culture of clostridium ljungdahlii and clostridium kluyveri with in-line product extraction. | carboxydotrophic bacteria (ctb) have received attention due to their ability to synthesize commodity chemicals from producer gas and synthesis gas (syngas). ctb have an important advantage of a high product selectivity compared to chemical catalysts. however, the product spectrum of wild-type ctb is narrow. our objective was to investigate whether a strategy of combining two wild-type bacterial strains into a single, continuously fed bioprocessing step would be promising to broaden the product s ... | 2016 | 27877166 |
| fatty acids production from hydrogen and carbon dioxide by mixed culture in the membrane biofilm reactor. | gasification of waste to syngas (h2/co2) is seen as a promising route to a circular economy. biological conversion of the gaseous compounds into a liquid fuel or chemical, preferably medium chain fatty acids (caproate and caprylate) is an attractive concept. this study for the first time demonstrated in-situ production of medium chain fatty acids from h2 and co2 in a hollow-fiber membrane biofilm reactor by mixed microbial culture. the hydrogen was for 100% utilized within the biofilms attached ... | 2013 | 23941982 |
| synthesis of heterologous mevalonic acid pathway enzymes in clostridium ljungdahlii for the conversion of fructose and of syngas to mevalonate and isoprene. | there is a growing interest in the use of microbial fermentation for the generation of high-demand, high-purity chemicals using cheap feedstocks in an environmentally friendly manner. one example explored here is the production of isoprene (c5h8), a hemiterpene, which is primarily polymerized to polyisoprene in synthetic rubber in tires but which can also be converted to c10 and c15 biofuels. the strictly anaerobic, acetogenic bacterium clostridium ljungdahlii, used in all of the work described ... | 2018 | 29054870 |
| transcriptomic profiles of clostridium ljungdahlii during lithotrophic growth with syngas or h2 and co2 compared to organotrophic growth with fructose. | clostridium ljungdahlii derives energy by lithotrophic and organotrophic acetogenesis. c. ljungdahlii was grown organotrophically with fructose and also lithotrophically, either with syngas - a gas mixture containing hydrogen (h2), carbon dioxide (co2), and carbon monoxide (co), or with h2 and co2. gene expression was compared quantitatively by microarrays using rna extracted from all three conditions. gene expression with fructose and with h2/co2 was compared by rna-seq. upregulated genes with ... | 2017 | 29030620 |
| a technique for lyopreservation of clostridium ljungdahlii in a biocomposite matrix for co absorption. | a system capable of biocatalytic conversion of distributed sources of single carbon gases such as carbon monoxide into hydrocarbons can be highly beneficial for developing commercially viable biotechnology applications in alternative energy. several anaerobic bacterial strains can be used for such conversion. the anaerobic carbon monoxide-fixing bacteria clostridium ljungdahlii ota1 is a model co assimilating microorganism that currently requires cryogenic temperature for storage of the viable s ... | 2017 | 28678828 |
| exploring biochemical pathways for mono-ethylene glycol (meg) synthesis from synthesis gas. | mono-ethylene glycol (meg) is an important petrochemical with widespread use in numerous consumer products. the current industrial meg-production process relies on non-renewable fossil fuel-based feedstocks, such as petroleum, natural gas, and naphtha; hence, it is useful to explore alternative routes of meg-synthesis from gases as they might provide a greener and more sustainable alternative to the current production methods. technologies of synthetic biology and metabolic engineering of microo ... | 2017 | 28433737 |
| biofilm formation by clostridium ljungdahlii is induced by sodium chloride stress: experimental evaluation and transcriptome analysis. | the acetogen clostridium ljungdahlii is capable of syngas fermentation and microbial electrosynthesis. biofilm formation could benefit both these applications, but was not yet reported for c. ljungdahlii. biofilm formation does not occur under standard growth conditions, but attachment or aggregation could be induced by different stresses. the strongest biofilm formation was observed with the addition of sodium chloride. after 3 days of incubation, the biomass volume attached to a plastic surfac ... | 2017 | 28118386 |
| characterization of clostridium ljungdahlii ota1: a non-autotrophic hyper ethanol-producing strain. | a clostridium ljungdahlii lab-isolated spontaneous-mutant strain, ota1, has been shown to produce twice as much ethanol as the c. ljungdahlii atcc 55383 strain when cultured in a mixotrophic medium containing fructose and syngas. whole-genome sequencing identified four unique single nucleotide polymorphisms (snps) in the c. ljungdahlii ota1 genome. among these, two snps were found in the gene coding for acsa and heml, enzymes involved in acetyl-coa formation from co/co2. homology models of the r ... | 2017 | 27866253 |
| in silico metabolic engineering of clostridium ljungdahlii for synthesis gas fermentation. | synthesis gas fermentation is one of the most promising routes to convert synthesis gas (syngas; mainly comprised of h2 and co) to renewable liquid fuels and chemicals by specialized bacteria. the most commonly studied syngas fermenting bacterium is clostridium ljungdahlii, which produces acetate and ethanol as its primary metabolic byproducts. engineering of c. ljungdahlii metabolism to overproduce ethanol, enhance the synthesize of the native byproducts lactate and 2,3-butanediol, and introduc ... | 2016 | 27720802 |
| co2 fixation by anaerobic non-photosynthetic mixotrophy for improved carbon conversion. | maximizing the conversion of biogenic carbon feedstocks into chemicals and fuels is essential for fermentation processes as feedstock costs and processing is commonly the greatest operating expense. unfortunately, for most fermentations, over one-third of sugar carbon is lost to co2 due to the decarboxylation of pyruvate to acetyl-coa and limitations in the reducing power of the bio-feedstock. here we show that anaerobic, non-photosynthetic mixotrophy, defined as the concurrent utilization of or ... | 2016 | 27687501 |
| bio-electrochemical synthesis of commodity chemicals by autotrophic acetogens utilizing co2 for environmental remediation. | bio-electrochemical synthesis (bes) is a technique in which electro-autotrophic bacteria such as clostridium ljungdahlii utilize electric currents as an electron source from the cathode to reduce co2 to extracellular, multicarbon, exquisite products through autotrophic conversion. the bes of volatile fatty acids and alcohols directly from co2 is a sustainable alternative for non-renewable, petroleum-based polymer production. this conversion of co2 implies reduction of greenhouse gas emissions. t ... | 2016 | 27581929 |
| expanding the molecular toolkit for the homoacetogen clostridium ljungdahlii. | increasing interest in homoacetogenic bacteria for the production of biochemicals and biofuels requisites the development of new genetic tools for these atypical production organisms. an attractive host for the conversion of synthesis gas or electricity into multi-carbon compounds is clostridium ljungdahlii. so far only limited achievements in modifying this organism towards the production of industrially relevant compounds have been made. therefore, there is still a strong need for developing n ... | 2016 | 27527841 |
| industrial acetogenic biocatalysts: a comparative metabolic and genomic analysis. | synthesis gas (syngas) fermentation by anaerobic acetogenic bacteria employing the wood-ljungdahl pathway is a bioprocess for production of biofuels and biocommodities. the major fermentation products of the most relevant biocatalytic strains (clostridium ljungdahlii, c. autoethanogenum, c. ragsdalei, and c. coskatii) are acetic acid and ethanol. a comparative metabolic and genomic analysis using the mentioned biocatalysts might offer targets for metabolic engineering and thus improve the produc ... | 2016 | 27458439 |
| a high gas fraction, reduced power, syngas bioprocessing method demonstrated with a clostridium ljungdahlii ota1 paper biocomposite. | we propose a novel approach to continuous bioprocessing of gases. a miniaturized, coated-paper strip, high gas fraction, biocomposite absorber has been developed using slowly shaken horizontal anaerobic tubes. concentrated clostridium ljungdahlii ota1 was used as a model system. these gas absorbers demonstrate elevated co mass transfer with low power input, reduced liquid requirements, elevated substrate consumption, and increased product secretion compared to shaken suspended cells. concentrate ... | 2016 | 26927418 |
| use of magnetic nanoparticles to enhance bioethanol production in syngas fermentation. | the effect of two types of nanoparticles on the enhancement of bioethanol production in syngas fermentation by clostridium ljungdahlii was examined. methyl-functionalized silica and methyl-functionalized cobalt ferrite-silica (cofe2o4@sio2-ch3) nanoparticles were used to improve syngas-water mass transfer. of these, cofe2o4@sio2-ch3 nanoparticles showed better enhancement of syngas mass transfer. the nanoparticles were recovered using a magnet and reused five times to evaluate reusability, and i ... | 2016 | 26773957 |
| metabolic modeling of synthesis gas fermentation in bubble column reactors. | a promising route to renewable liquid fuels and chemicals is the fermentation of synthesis gas (syngas) streams to synthesize desired products such as ethanol and 2,3-butanediol. while commercial development of syngas fermentation technology is underway, an unmet need is the development of integrated metabolic and transport models for industrially relevant syngas bubble column reactors. | 2015 | 26106448 |
| carbon dioxide reduction by mixed and pure cultures in microbial electrosynthesis using an assembly of graphite felt and stainless steel as a cathode. | carbon dioxide (co2) reduction to multi-carbon compounds at the cathode using chemolithoautotrophs is an emerging application of microbial electrosynthesis (mes). in this study, co2 reduction in mes was investigated at hydrogen evolving potentials, separately by a mixed culture and clostridium ljungdahlii, using a graphite felt and stainless steel assembly as cathode. the mixed culture reactor produced acetate at the maximum rate of 1.3 mm d(-1), along with methane and hydrogen at -1.1 v/ag/agcl ... | 2015 | 26066971 |
| physiological response of clostridium ljungdahlii dsm 13528 of ethanol production under different fermentation conditions. | in this study, cell growth, gene expression and ethanol production were monitored under different fermentation conditions. like its heterotrophical abe-producing relatives, a switch from acidogenesis to solventogenesis of clostridium ljungdahlii during the autotrophic fermentation with co/co2 could be observed, which occurred surprisingly in the late-log phase rather than in the transition phase. the gene expression profiles indicated that aor1, one of the putative aldehyde oxidoreductases in it ... | 2015 | 25496952 |
| converting carbon dioxide to butyrate with an engineered strain of clostridium ljungdahlii. | microbial conversion of carbon dioxide to organic commodities via syngas metabolism or microbial electrosynthesis is an attractive option for production of renewable biocommodities. the recent development of an initial genetic toolbox for the acetogen clostridium ljungdahlii has suggested that c. ljungdahlii may be an effective chassis for such conversions. this possibility was evaluated by engineering a strain to produce butyrate, a valuable commodity that is not a natural product of c. ljungda ... | 2014 | 25336453 |
| enhancement of bioethanol production in syngas fermentation with clostridium ljungdahlii using nanoparticles. | in this study, nanoparticles were used to enhance bioethanol production in syngas fermentation by clostridium ljungdahlii. six types of nanoparticles were tested: palladium on carbon, palladium on alumina, silica, hydroxyl-functionalized single-walled carbon nanotubes, alumina, and iron(iii) oxide. of these, silica nanoparticles at a concentration of 0.3 wt% were the best at enhancing gas-liquid mass transfer. the hydrophilic surfaces of silica nanoparticles were modified with hydrophobic functi ... | 2014 | 24703605 |
| kinetic studies on fermentative production of biofuel from synthesis gas using clostridium ljungdahlii. | the intrinsic growth, substrate uptake, and product formation biokinetic parameters were obtained for the anaerobic bacterium, clostridium ljungdahlii, grown on synthesis gas in various pressurized batch bioreactors. a dual-substrate growth kinetic model using luong for co and monod for h2 was used to describe the growth kinetics of the bacterium on these substrates. the maximum specific growth rate (μ(max) = 0.195 h(-1)) and monod constants for co (k s,co = 0.855 atm) and h2 (k(s,h2) = 0.412 at ... | 2014 | 24672390 |
| characterizing acetogenic metabolism using a genome-scale metabolic reconstruction of clostridium ljungdahlii. | the metabolic capabilities of acetogens to ferment a wide range of sugars, to grow autotrophically on h2/co2, and more importantly on synthesis gas (h2/co/co2) make them very attractive candidates as production hosts for biofuels and biocommodities. acetogenic metabolism is considered one of the earliest modes of bacterial metabolism. a thorough understanding of various factors governing the metabolism, in particular energy conservation mechanisms, is critical for metabolic engineering of acetog ... | 2013 | 24274140 |
| rna-seq-based comparative transcriptome analysis of the syngas-utilizing bacterium clostridium ljungdahlii dsm 13528 grown autotrophically and heterotrophically. | clostridium ljungdahlii dsm 13528 represents a promising platform organism for production of a whole variety of different biofuels and biochemicals from syngas. although the publication of its genome gave us the first possibility to understand the molecular mechanism for carbon utilization, reports on the profiling of the transcriptome were unavailable. in this study, rna-seq-based global transcriptome analysis was performed to compare the transcriptomes of c. ljungdahlii grown on co-co2 with th ... | 2013 | 24056499 |
| evaluation of clostridium ljungdahlii dsm 13528 reference genes in gene expression studies by qrt-pcr. | clostridium ljungdahlii dsm 13528 is a promising platform organism for biofuel production from syngas. gene expression analysis permits a better understanding of the important molecular biological characteristics of this organism, such as carbon fixation and solvent adaptation. normalization is a prerequisite for accurate gene expression analysis, but until now, no valid reference genes have been proposed for quantitative real-time polymerase chain reaction (qrt-pcr) analysis of c. ljungdahlii d ... | 2013 | 23651807 |
| a genetic system for clostridium ljungdahlii: a chassis for autotrophic production of biocommodities and a model homoacetogen. | methods for genetic manipulation of clostridium ljungdahlii are of interest because of the potential for production of fuels and other biocommodities from carbon dioxide via microbial electrosynthesis or more traditional modes of autotrophy with hydrogen or carbon monoxide as the electron donor. furthermore, acetogenesis plays an important role in the global carbon cycle. gene deletion strategies required for physiological studies of c. ljungdahlii have not previously been demonstrated. an elect ... | 2013 | 23204413 |
| biocatalytic reduction of short-chain carboxylic acids into their corresponding alcohols with syngas fermentation. | short-chain carboxylic acids generated by various mixed- or pure-culture fermentation processes have been considered valuable precursors for production of bioalcohols. while conversion of carboxylic acids into alcohols is routinely performed with catalytic hydrogenation or with strong chemical reducing agents, here, a biological conversion route was explored. the potential of carboxydotrophic bacteria, such as clostridium ljungdahlii and clostridium ragsdalei, as biocatalysts for conversion of s ... | 2013 | 23172270 |
| tracing carbon monoxide uptake by clostridium ljungdahlii during ethanol fermentation using (13)c-enrichment technique. | conversion of synthesis gas (co and h2) to ethanol can be an alternative, promising technology to produce biofuels from renewable biomass. to distinguish microbial utilization of carbon source between fructose and synthesis gas co and to evaluate biological production of ethanol from co, we adopted the (13)c-enrichment of the co substrate and hypothesized that the residual increase in δ(13)c of the cell biomass would reflect the increased contribution of (13)c-enriched co. addition of synthesis ... | 2013 | 22940807 |