Clostridium acetobutylicum: Difference between revisions
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[http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6W9T-4B84WBR-2&_user=4429&_coverDate=04%2F30%2F2004&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000059602&_version=1&_urlVersion=0&_userid=4429&md5=1983232403654aed9fef726e9018531c#bib1 P. Durre and C. Hollergschwandner, Initiation of endospore formation in Clostridium acetobutylicum, Anaerobe 10 (2004), pp. 69–74.] | [http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6W9T-4B84WBR-2&_user=4429&_coverDate=04%2F30%2F2004&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000059602&_version=1&_urlVersion=0&_userid=4429&md5=1983232403654aed9fef726e9018531c#bib1 P. Durre and C. Hollergschwandner, Initiation of endospore formation in Clostridium acetobutylicum, Anaerobe 10 (2004), pp. 69–74.] | ||
[http://iai.asm.org/cgi/content/abstract/56/4/926 Gimenez, J.A. and H. Sugiyama. 1988. Comparison of toxins of Clostridium butyricum and Clostridium botulinum type E. Infection and Immunity 56:926-929.] | |||
Edited by Mark Hower, student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano | Edited by Mark Hower, student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano |
Revision as of 00:52, 3 May 2007
A Microbial Biorealm page on the genus Clostridium acetobutylicum
![](/images/e/e8/Clostridium.jpg)
Classification
Higher order taxa
Bacteria (Domain); Firmicutes (Phylum); Clostridia (Class); Clostridiales (Order); Clostridiaceae (Family); Clostridium (Genus)
Species
Clostridium acetobutylicum
Clostridium acetobutylicum ATCC 824 is considered the type strain.
NCBI: Taxonomy |
Description and significance
Clostridium acetobutylicum is a Gram positive bacillus. C. acetobutylicum is a soil dwelling and mesophilic with optimal temperatures of 10-65C.It is anaerobic and saccharolytic capable of producing a number of different commercially useful products; most notably acetone, ethanol and butanol.
It was first isolated between 1912 and 1914. Chaim Weizmann cultured the bacteria to be used to produce acetone, ethanol and butanol (ABE method) which was used to produce TNT and gunpowder in the first World War. Following WWI, the ABE process was widely used until the 1950's when petrochemical processes were more cost-effective due to the cost and availability of petroleum fuel sources.
The recent fossil fuel crisis has spurred more research into C. acetobutylicum and the utilization of the ABE process.
Describe the appearance, habitat, etc. of the organism, and why it is important enough to have its genome sequenced. Describe how and where it was isolated.
Include a picture or two (with sources) if you can find them.
Genome structure
The genome of Clostridium acetobutylicum ATCC 824 has been sequenced. This is the model strain for solvent-producing bacteria. It consists of one circular chromosome with 3,940,880 bp. The chromosome contains 11 operons coding for ribosomes, each of which is near the oriC and oriented in the direction of the leading strand of the replication fork. This is a characteristic commonly observed known as gene dosage, in which highly transcribed genes are placed near the oriC. There is little strand bias with approximately 51.5% of genes being transcribed from forward strand and 49.5% from the complementary strand.
In addition, the genome consists of one megaplasmid involved with solvent production and aptly named pSOL1. pSOL1 contains 192,000 bp and codes for 178 polypeptides. Examination of the plasmid indicates no obvious bias in the coding strand. pSOL1 contains four genes which are vital for alcohol and acetone production and the loss of this plasmid contributes to degeneration of the strain after many vegetative transfers or being maintained in a continuous culture. Further, mutants lacking these genes and unable to produce solvent resume acetone and alcohol production upon complementation of the genes via plasmids.
Examination of other strains of the organism such as ATCC 4259 have demonstrated that solvent producing genes again exist on the plasmid, named pWEIZ. Degeneration of the strain due to serial culturing is likely due to loss of this plasmid. Interestingly, these degenerate strains also do not sporulate spurring the idea that genes involved in sporulation also exist on the plasmid.
Describe the size and content of the genome. How many chromosomes? Circular or linear? Other interesting features? What is known about its sequence? Does it have any plasmids? Are they important to the organism's lifestyle?
Cell structure and metabolism
![](/images/thumb/5/50/Metabolism.jpeg/300px-Metabolism.jpeg)
Cell structure and development is characterized by the development of an endospore when exposed to unfavorable conditions.
The pathways which produce solvents are those most notable in C. acetobutylicum. Acetone, acetate, butanol, butyrate, and ethanol are all made from acetyl-CoA.
Mutants which do not produce acetone or alcohol, such as mutant M5 of strain C. acetobutylicum ATCC 824 have been shown to lack of three enzymes in vitro: butyraldehyde dehydrogenase (BYDH), acetoacetate decarboxylase(AADC), and acetoacetyl-coenzyme A:acetate/butyrate:coenzyme A-transferase (CoAT). These enzymes are coded for on the plasmid within the sol operon by the following genes: AADC (adc), CoAT (ctfA, ctfB) and BYDH (aad).
In addition, C. acetobutylicum codes for many proteins that aid in the breakdown of xylan, levan, pectin, starch, and other polysaccharides. Interestingly, while the presence of genes which commonly code for cellusomes, protein complexes which breakdown crystalline cellulose, has been detected, the organism is unable to grow solely on cellulose substrates.
Nitrogen fixation operon is conserved see article 1.
Describe any interesting features and/or cell structures; how it gains energy; what important molecules it produces.
Ecology
Describe any interactions with other organisms (included eukaryotes), contributions to the environment, effect on environment, etc.
Pathology
C. acetobutylicum is completely benign to both plants and animals, however, many other species in the Clostridium genus are known pathogens, including: Clostridium difficile, Clostridium botulinum, Clostridium tetani, and Clostridium perfringen. In particular, C. botulinum and C. tetani, produce some of the most deadly neurotoxins known.
C. acetobutylicum has been found in the human colon, however, it is primarily not known to be a part of normal human flora. In addition, because the organism does not appear to be toxic to mammals through the production of intracellular or extracellular substances the organism would have to be present in enormous quantities to produces any threat.
The only issue of pathology with C. acetobutylicum is acquiring genes from pathogenic Clostridium such as C. tetani or C. botulinum. While there are no reported cases of C. acetobutylicum acquiring these genes, there have been incidents in the literature in which other Clostridium species have caused infant botulism with toxins very similar to those present in C. botulinum. The similarity of the toxins suggest that the normally non-toxigenic Clostridium strain acquired genes from C. botulinum.
How does this organism cause disease? Human, animal, plant hosts? Virulence factors, as well as patient symptoms.
Application to Biotechnology
Does this organism produce any useful compounds or enzymes? What are they and how are they used?
Current Research
Enter summaries of the most recent research here--at least three required
References
Taxonomy:NCBI
Cornillot E, Soucaille P. Solvent forming genes in Clostridia. Nature. 1996;380:489.
Edited by Mark Hower, student of Rachel Larsen and Kit Pogliano