A Life with Acetogens, Thermophiles, and Cellulolytic Anaerobes

Ljungdahl, Lars G.

doi:10.1146/annurev.micro.091208.073617

Cited by 65 publications

(48 citation statements)

References 81 publications

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“…The reductive acetyl-CoA pathway, or Wood-Ljungdahl (WL) pathway, was discovered and elucidated in acetogenic bacteria-anaerobic bacteria, which form acetate from H 2 and CO 2 -mainly in the laboratories of Harland G. Wood and Lars G. Ljungdahl (Ljungdahl & Wood 1969, Ljungdahl 1986, Drake et al 2008, Ljungdahl 2009). It is a relatively simple pathway in which two molecules of CO 2 are combined directly in a noncyclic way to acetyl-CoA.…”

Section: Reductive Acetyl-coa Pathwaymentioning

confidence: 99%

Beyond the Calvin Cycle: Autotrophic Carbon Fixation in the Ocean

Hügler

Sievert

2011

Annu. Rev. Mar. Sci.

527

486

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Organisms capable of autotrophic metabolism assimilate inorganic carbon into organic carbon. They form an integral part of ecosystems by making an otherwise unavailable form of carbon available to other organisms, a central component of the global carbon cycle. For many years, the doctrine prevailed that the Calvin-Benson-Bassham (CBB) cycle is the only biochemical autotrophic CO2 fixation pathway of significance in the ocean. However, ecological, biochemical, and genomic studies carried out over the last decade have not only elucidated new pathways but also shown that autotrophic carbon fixation via pathways other than the CBB cycle can be significant. This has ramifications for our understanding of the carbon cycle and energy flow in the ocean. Here, we review the recent discoveries in the field of autotrophic carbon fixation, including the biochemistry and evolution of the different pathways, as well as their ecological relevance in various oceanic ecosystems.

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Section: Reductive Acetyl-coa Pathwaymentioning

confidence: 99%

Beyond the Calvin Cycle: Autotrophic Carbon Fixation in the Ocean

Hügler

Sievert

2011

Annu. Rev. Mar. Sci.

527

486

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“…Clostridium organisms (e.g., C. leptum and C. coccoides) in the human intestinal microbiota provide a number of health benefits and immune protection (8). The genus Clostridium also includes organisms of importance to detoxification, remediation, and the carbon cycle, such as acetogens, which use the Wood-Ljungdahl pathway to fix CO 2 and generate enormous quantities of acetate and which are responsible for fixing ϳ20% of the CO 2 on earth (9). Several Clostridium species (e.g., C. acetobutylicum, C. pasteurianum, C. thermocellum, and C. beijerinckii) have found important biotechnological applications in the production of chemicals.…”

Section: Introductionmentioning

confidence: 99%

The Clostridium Sporulation Programs: Diversity and Preservation of Endospore Differentiation

Al-Hinai

Jones

Papoutsakis

2015

Microbiol Mol Biol Rev

156

190

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SUMMARY Bacillus and Clostridium organisms initiate the sporulation process when unfavorable conditions are detected. The sporulation process is a carefully orchestrated cascade of events at both the transcriptional and posttranslational levels involving a multitude of sigma factors, transcription factors, proteases, and phosphatases. Like Bacillus genomes, sequenced Clostridium genomes contain genes for all major sporulation-specific transcription and sigma factors ( spo0A , sigH , sigF , sigE , sigG , and sigK ) that orchestrate the sporulation program. However, recent studies have shown that there are substantial differences in the sporulation programs between the two genera as well as among different Clostridium species. First, in the absence of a Bacillus -like phosphorelay system, activation of Spo0A in Clostridium organisms is carried out by a number of orphan histidine kinases. Second, downstream of Spo0A, the transcriptional and posttranslational regulation of the canonical set of four sporulation-specific sigma factors (σ F , σ E , σ G , and σ K ) display different patterns, not only compared to Bacillus but also among Clostridium organisms. Finally, recent studies demonstrated that σ K , the last sigma factor to be activated according to the Bacillus subtilis model, is involved in the very early stages of sporulation in Clostridium acetobutylicum , C. perfringens , and C. botulinum as well as in the very late stages of spore maturation in C. acetobutylicum . Despite profound differences in initiation, propagation, and orchestration of expression of spore morphogenetic components, these findings demonstrate not only the robustness of the endospore sporulation program but also the plasticity of the program to generate different complex phenotypes, some apparently regulated at the epigenetic level.

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“…So far, a variety of renewable resources, such as wheat straw, corn stover and corn Wber, has been employed for the production of butanol [19,23]. Since no microorganism currently can eYciently hydrolyze lignocellulosic biomass to produce butanol, both physical-chemical pretreatment [28,36] and enzymatic hydrolysis [31,33,34] are required.…”

Section: Introductionmentioning

confidence: 99%

Butanol production by Clostridium beijerinckii ATCC 55025 from wheat bran

Liu

et al. 2010

J Ind Microbiol Biotechnol

176

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Wheat bran, a by-product of the wheat milling industry, consists mainly of hemicellulose, starch and protein. In this study, the hydrolysate of wheat bran pretreated with dilute sulfuric acid was used as a substrate to produce ABE (acetone, butanol and ethanol) using Clostridium beijerinckii ATCC 55025. The wheat bran hydrolysate contained 53.1 g/l total reducing sugars, including 21.3 g/l of glucose, 17.4 g/l of xylose and 10.6 g/l of arabinose. C. beijerinckii ATCC 55025 can utilize hexose and pentose simultaneously in the hydrolysate to produce ABE. After 72 h of fermentation, the total ABE in the system was 11.8 g/l, of which acetone, butanol and ethanol were 2.2, 8.8 and 0.8 g/l, respectively. The fermentation resulted in an ABE yield of 0.32 and productivity of 0.16 g l(-1) h(-1). This study suggests that wheat bran can be a potential renewable resource for ABE fermentation.

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A Life with Acetogens, Thermophiles, and Cellulolytic Anaerobes

Cited by 65 publications

References 81 publications

Beyond the Calvin Cycle: Autotrophic Carbon Fixation in the Ocean

Beyond the Calvin Cycle: Autotrophic Carbon Fixation in the Ocean

The Clostridium Sporulation Programs: Diversity and Preservation of Endospore Differentiation

Butanol production by Clostridium beijerinckii ATCC 55025 from wheat bran

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