| clostridium carboxidivorans sp. nov., a solvent-producing clostridium isolated from an agricultural settling lagoon, and reclassification of the acetogen clostridium scatologenes strain sl1 as clostridium drakei sp. nov. | a novel solvent-producing, anaerobic clostridium, strain p7(t), was isolated from sediment from an agricultural settling lagoon after enrichment with co as the substrate. the metabolism of this gram-positive, motile, spore-forming rod was primarily acetogenic. acetate, ethanol, butyrate and butanol were the end-products of metabolism. strain p7(t) grew on co, h(2)/co(2), glucose, galactose, fructose, xylose, mannose, cellobiose, trehalose, cellulose, starch, pectin, citrate, glycerol, ethanol, p ... | 2005 | 16166714 |
| fermentation of biomass-generated synthesis gas: effects of nitric oxide. | the production of renewable fuels, such as ethanol, has been steadily increasing owing to the need for a reduced dependency on fossil fuels. it was demonstrated previously that biomass-generated synthesis gas (biomass-syngas) can be converted to ethanol and acetic acid using a microbial catalyst. the biomass-syngas (primarily co, co(2), h(2), and n(2)) was generated in a fluidized-bed gasifier and used as a substrate for clostridium carboxidivorans p7(t). results showed that the cells stopped co ... | 2007 | 17171719 |
| clostridium nitrophenolicum sp. nov., a novel anaerobic p-nitrophenol-degrading bacterium, isolated from a subsurface soil sample. | an obligate anaerobic, mesophilic, motile and endospore-forming bacterium, designated 1d(t), was isolated from a subsurface soil sample. the young culture of strain 1d(t) was gram-positive and formed oval spores that were central in position. based on the biochemical, chemotaxonomic and physiological data, strain 1d(t) appears to be a member of the genus clostridium. strain 1d(t) was found to be capable of degrading p-nitrophenol (pnp) at a concentration of 0.5 mm under anaerobic conditions as r ... | 2007 | 17684276 |
| carbon metabolism of the moderately acid-tolerant acetogen clostridium drakei isolated from peat. | a moderately acid-tolerant, malodorous bacterium, strain fp, was isolated from peat that had a pore water ph of c. 4.2. the 16s rrna gene sequence of fp was closely related to that of acetogens clostridium drakei, clostridium scatologenes, and clostridium carboxidivorans. the dna-dna reassociation values obtained with dna from fp and that of these three acetogens approximated 80%, 64%, and 59%, respectively, indicating that fp was a new strain of c. drakei. fp had broad ph and temperature ranges ... | 2008 | 18710398 |
| 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 |
| genome sequence of the solvent-producing bacterium clostridium carboxidivorans strain p7t. | clostridium carboxidivorans strain p7(t) is a strictly anaerobic acetogenic bacterium that produces acetate, ethanol, butanol, and butyrate. the c. carboxidivorans genome contains all the genes for the carbonyl branch of the wood-ljungdahl pathway for co(2) fixation, and it encodes enzymes for conversion of acetyl coenzyme a into butanol and butyrate. | 2010 | 20729368 |
| genomic analysis of carbon monoxide utilization and butanol production by clostridium carboxidivorans strain p7. | increasing demand for the production of renewable fuels has recently generated a particular interest in microbial production of butanol. anaerobic bacteria, such as clostridium spp., can naturally convert carbohydrates into a variety of primary products, including alcohols like butanol. the genetics of microorganisms like clostridium acetobutylicum have been well studied and their solvent-producing metabolic pathways characterized. in contrast, less is known about the genetics of clostridium spp ... | 2010 | 20885952 |
| 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 |
| reduction of acetone to isopropanol using producer gas fermenting microbes. | gasification-fermentation is an emerging technology for the conversion of lignocellulosic materials into biofuels and specialty chemicals. for effective utilization of producer gas by fermenting bacteria, tar compounds produced in the gasification process are often removed by wet scrubbing techniques using acetone. in a preliminary study using biomass generated producer gas scrubbed with acetone, an accumulation of acetone and subsequent isopropanol production was observed. the effect of 2 g/l a ... | 2011 | 21557204 |
| formate production through carbon dioxide hydrogenation with recombinant whole cell biocatalysts. | the biological conversion of co2 and h2 into formate offers a sustainable route to a valuable commodity chemical through co2 fixation, and a chemical form of hydrogen fuel storage. here we report the first example of co2 hydrogenation utilising engineered whole-cell biocatalysts. escherichia coli jm109(de3) cells transformed for overexpression of either native formate dehydrogenase (fdh), the fdh from clostridium carboxidivorans, or genes from pyrococcus furiosus and methanobacterium thermoformi ... | 2014 | 24814397 |
| clostridium carboxidivorans strain p7t recombinant formate dehydrogenase catalyzes reduction of co(2) to formate. | recombinant formate dehydrogenase from the acetogen clostridium carboxidivorans strain p7(t), expressed in escherichia coli, shows particular activity towards nadh-dependent carbon dioxide reduction to formate due to the relative binding affinities of the substrates and products. the enzyme retains activity over 2 days at 4°c under oxic conditions. | 2013 | 23144135 |
| butanol and hexanol production in clostridium carboxidivorans syngas fermentation: medium development and culture techniques. | clostridium carboxidivorans was grown on model syngas (co:h2:co2 [70:20:10]) in a defined nutrient medium with concentrations of nitrogen, phosphate and trace metals formulated to enhance production of higher alcohols. c. carboxidivorans was successfully grown in a limited defined medium (no yeast extract, no mes buffer and minimal complex chemical inputs) using an improved fermentation protocol. low partial pressure of co in the headspace, coupled with restricted mass transfer for co and h2, wa ... | 2015 | 25935391 |
| 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 |
| heterologous expression of the clostridium carboxidivorans co dehydrogenase alone or together with the acetyl coenzyme a synthase enables both reduction of co2 and oxidation of co by clostridium acetobutylicum. | with recent advances in synthetic biology, co2 could be utilized as a carbon feedstock by native or engineered organisms, assuming the availability of electrons. two key enzymes used in autotrophic co2 fixation are the co dehydrogenase (codh) and acetyl coenzyme a (acetyl-coa) synthase (acs), which form a bifunctional heterotetrameric complex. the codh/acs complex can reversibly catalyze co2 to co, effectively enabling a biological water-gas shift reaction at ambient temperatures and pressures. ... | 2017 | 28625981 |
| production of acids and alcohols from syngas in a two-stage continuous fermentation process. | a two-stage continuous system with two stirred tank reactors in series was utilized to perform syngas fermentation using clostridium carboxidivorans. the first bioreactor (bioreactor 1) was maintained at ph 6 to promote acidogenesis and the second one (bioreactor 2) at ph 5 to stimulate solventogenesis. both reactors were operated in continuous mode by feeding syngas (co:co2:h2:n2; 30:10:20:40; vol%) at a constant flow rate while supplying a nutrient medium at different flow rates of 8.1, 15, 22 ... | 2018 | 29348063 |
| effects of zinc on the production of alcohol by clostridium carboxidivorans p7 using model syngas. | renewable energy, including biofuels such as ethanol and butanol from syngas bioconversed by clostridium carboxidivorans p7, has been drawing extensive attention due to the fossil energy depletion and global eco-environmental issues. effects of zinc on the growth and metabolites of c. carboxidivorans p7 were investigated with model syngas as the carbon source. the cell concentration was doubled, the ethanol content increased 3.02-fold and the butanol content increased 7.60-fold, the hexanol cont ... | 2018 | 29204741 |
| hydrogen and carbon dioxide mixed culture fermentation in a hollow-fiber membrane biofilm reactor at 25 °c. | there have been no reports of h2 and co2 mixed-culture fermentation (mcf) at 25 °c in a hollow-fiber membrane biofilm reactor (hfmbr). in this study, h2 and co2 mcf were conducted in an hfmbr at 25 °c producing metabolites including acetate, ethanol, butyrate, and caproate. compared to pure culture fermentation (i.e., clostridium carboxidivorans p7), the mcf in hfmbr at 25 °c produced a higher concentration of caproate in this study (3.4 g/l in batch 1 and 5.7 g/l in batch 2). the dominant gener ... | 2017 | 29091851 |
| deciphering clostridium metabolism and its responses to bioreactor mass transfer during syngas fermentation. | this study used 13c tracers and dynamic labeling to reveal metabolic features (nutrients requirements, pathway delineation and metabolite turnover rates) of clostridium carboxidivorans p7, a model strain for industrial syngas fermentation, and its implication with bioreactor mass transfer. p7 shows poor activity for synthesizing amino acids (e.g., phenylalanine) and thus, needs rich medium for cell growth. the strain has multiple carbon fixation routes (wood-ljungdahl pathway, pyruvate:ferredoxi ... | 2017 | 28855713 |
| glucose bioconversion profile in the syngas-metabolizing species clostridium carboxidivorans. | some clostridia produce alcohols (ethanol, butanol, hexanol) from gases (co, co2, h2) and others from carbohydrates (e.g., glucose). c. carboxidivorans can metabolize both gases as well as glucose. however, its bioconversion profile on glucose had not been reported. it was observed that c. carboxidivorans does not follow a typical solventogenic stage when grown on glucose. indeed, at ph 6.2, it produced first a broad range of acids (acetic, butyric, hexanoic, formic, and lactic acids), several o ... | 2017 | 28803105 |
| enhanced alcohol titre and ratio in carbon monoxide-rich off-gas fermentation of clostridium carboxidivorans through combination of trace metals optimization with variable-temperature cultivation. | bioconversion of c1 gases to produce chemicals has good application prospects. here, the combination of trace metals optimization using a statistical method with variable-temperature cultivation was used to enhance alcohol synthesis during co-rich off-gas fermentation by clostridium carboxidivorans p7. based on atcc medium 1754, the optimum concentration of the trace metals was found to be 5-fold ni2+, co2+, seo42+, and wo42+; 3.48-fold cu2+; 0.55-fold moo42+; 0.5-fold zn2+ and (nh4)2so4·feso4·6 ... | 2017 | 28521234 |
| production of chemicals from c1 gases (co, co2) by clostridium carboxidivorans. | bioprocesses in conventional second generation biorefineries are mainly based on the fermentation of sugars obtained from lignocellulosic biomass or agro-industrial wastes. an alternative to this process consists in gasifying those same feedstocks or even other carbon-containing materials to obtain syngas which can also be fermented by some anaerobic bacteria to produce chemicals or fuels. carbon monoxide, carbon dioxide and hydrogen, which are the main components of syngas, are also found in so ... | 2017 | 28160118 |
| effects of end products on fermentation profiles in clostridium carboxidivorans p7 for syngas fermentation. | clostridium carboxidivorans p7 is a strict anaerobic bacterium capable of converting syngas to biofuels. however, its fermentation profiles is poorly understood. here, various end-products, including acetic acid, butyric acid, hexanoic acid, ethanol and butanol were supplemented to evaluate their effects on fermentation profiles in c. carboxidivorans at two temperatures. at 37°c, fatty acids addition likely led to more corresponding alcohols production. at 25°c, c2 and c4 fatty acids supplementa ... | 2016 | 27459682 |
| carbon monoxide bioconversion to butanol-ethanol by clostridium carboxidivorans: kinetics and toxicity of alcohols. | butanol production from carbon monoxide-rich waste gases or syngas is an attractive novel alternative to the conventional acetone-butanol-ethanol (abe) fermentation. solvent toxicity is a key factor reported in abe fermentation with carbohydrates as substrates. however, in the gas-fermentation process, kinetic aspects and the inhibition effect of solvents have not thoroughly been studied. therefore, different batch bottle experiments were carried out with the bacterial species clostridium carbox ... | 2016 | 26921183 |
| efficient butanol-ethanol (b-e) production from carbon monoxide fermentation by clostridium carboxidivorans. | the fermentation of waste gases rich in carbon monoxide using acetogens is an efficient way to obtain valuable biofuels like ethanol and butanol. different experiments were carried out with the bacterial species clostridium carboxidivorans as biocatalyst. in batch assays with no ph regulation, after complete substrate exhaustion, acetic acid, butyric acid, and ethanol were detected while only negligible butanol production was observed. on the other side, in bioreactors, with continuous carbon mo ... | 2016 | 26810079 |
| graphene oxide and h2 production from bioelectrochemical graphite oxidation. | graphene oxide (go) is an emerging material for energy and environmental applications, but it has been primarily produced using chemical processes involving high energy consumption and hazardous chemicals. in this study, we reported a new bioelectrochemical method to produce go from graphite under ambient conditions without chemical amendments, value-added organic compounds and high rate h2 were also produced. compared with abiotic electrochemical electrolysis control, the microbial assisted gra ... | 2015 | 26573014 |
| 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 |
| conversion of sewage sludge to commodity chemicals via syngas fermentation. | gasification of sewage sludge allows the recovery of energy, and produces a mix of co, co₂and h₂called synthesis gas (or syngas), which can be fermented by acetogenic bacteria to added-value products. this work presents the conversion of syngas to organic acids and alcohols using both pure and mixed cultures. pure culture kinetic experiments with clostridium carboxidivorans p7 resulted in the production of high concentrations of acetate (454 mgc/l) and ethanol (167 mgc/l). the ph was the main fa ... | 2015 | 26204073 |
| complete genome sequence of clostridium carboxidivorans p7(t), a syngas-fermenting bacterium capable of producing long-chain alcohols. | clostridium carboxidivorans p7(t) is an anaerobe that can ferment syngas (mainly co or co2 and h2) to produce acids (acetic and butyric acid), ethanol and long-chain alcohols (butanol and hexanol). here, the first complete genome sequence for c. carboxidivorans p7(t) is presented. this anaerobic bacterium harbors a 5,732,880bp circular chromosome and a 19,902bp mega-plasmid with 4951 and 22 coding dna sequence (cds), respectively. | 2015 | 26193629 |
| incubation at 25 °c prevents acid crash and enhances alcohol production in clostridium carboxidivorans p7. | incubation of carboxydotrophs at 37 °c provides optimal conditions for their growth. however, a fast accumulation of organic acids, specifically acetate, during the exponential growth phase may result in low alcohol production and substrate consumption due to a phenomenon known as "acid crash". the present work investigates growth and productivity of clostridium carboxidivorans p7 at two incubation temperatures. at 37 °c the culture was not able to override the "acid crash", resulting in low eth ... | 2015 | 26046429 |
| formate production through biocatalysis. | the generation of formate from co₂ provides a method for sequestration of this greenhouse gas as well as the production of a valuable commodity chemical and stabilized form of hydrogen fuel. formate dehydrogenases are enzymes with the potential to catalyze this reaction; however they generally favor the reverse process, i.e., formate oxidation. by contrast, the formate dehydrogenase of the acetogen clostridium carboxidivorans has been found to preferentially catalyze the reduction of co₂. this i ... | 2017 | 23841981 |
| physiological response of clostridium carboxidivorans during conversion of synthesis gas to solvents in a gas-fed bioreactor. | clostridium carboxidivorans p7 is one of three microbial catalysts capable of fermenting synthesis gas (mainly co, co(2) , and h(2) ) to produce the liquid biofuels ethanol and butanol. gasification of feedstocks to produce synthesis gas (syngas), followed by microbial conversion to solvents, greatly expands the diversity of suitable feedstocks that can be used for biofuel production beyond commonly used food and energy crops to include agricultural, industrial, and municipal waste streams. c. c ... | 2012 | 22566280 |