Formation and characterization of non-growth states in <it>Clostridium thermocellum</it>: spores and L-forms
<p>Abstract</p> <p>Background</p> <p><it>Clostridium thermocellum</it> is an anaerobic thermophilic bacterium that exhibits high levels of cellulose solublization and produces ethanol as an end product of its metabolism. Using cellulosic biomass as a feedsto...
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| Format: | Article |
| Language: | English |
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BMC
2012-08-01
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| Series: | BMC Microbiology |
| Online Access: | http://www.biomedcentral.com/1471-2180/12/180 |
| _version_ | 1830206179385540608 |
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| author | Mearls Elizabeth B Izquierdo Javier A Lynd Lee R |
| author_facet | Mearls Elizabeth B Izquierdo Javier A Lynd Lee R |
| author_sort | Mearls Elizabeth B |
| collection | DOAJ |
| description | <p>Abstract</p> <p>Background</p> <p><it>Clostridium thermocellum</it> is an anaerobic thermophilic bacterium that exhibits high levels of cellulose solublization and produces ethanol as an end product of its metabolism. Using cellulosic biomass as a feedstock for fuel production is an attractive prospect, however, growth arrest can negatively impact ethanol production by fermentative microorganisms such as <it>C. thermocellum</it>. Understanding conditions that lead to non-growth states in <it>C. thermocellum </it>can positively influence process design and culturing conditions in order to optimize ethanol production in an industrial setting.</p> <p>Results</p> <p>We report here that <it>Clostridium thermocellum</it> ATCC 27405 enters non-growth states in response to specific growth conditions. Non-growth states include the formation of spores and a L-form-like state in which the cells cease to grow or produce the normal end products of metabolism. Unlike other sporulating organisms, we did not observe sporulation of <it>C. thermocellum</it> in low carbon or nitrogen environments. However, sporulation did occur in response to transfers between soluble and insoluble substrates, resulting in approximately 7% mature spores. Exposure to oxygen caused a similar sporulation response. Starvation conditions during continuous culture did not result in spore formation, but caused the majority of cells to transition to a L-form state. Both spores and L-forms were determined to be viable. Spores exhibited enhanced survival in response to high temperature and prolonged storage compared to L-forms and vegetative cells. However, L-forms exhibited faster recovery compared to both spores and stationary phase cells when cultured in rich media.</p> <p>Conclusions</p> <p>Both spores and L-forms cease to produce ethanol, but provide other advantages for <it>C. thermocellum</it> including enhanced survival for spores and faster recovery for L-forms. Understanding the conditions that give rise to these two different non-growth states, and the implications that each has for enabling or enhancing <it>C. thermocellum</it> survival may promote the efficient cultivation of this organism and aid in its development as an industrial microorganism.</p> |
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| institution | Directory Open Access Journal |
| issn | 1471-2180 |
| language | English |
| last_indexed | 2024-12-18T04:08:24Z |
| publishDate | 2012-08-01 |
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| series | BMC Microbiology |
| spelling | doaj.art-675123c2718843039499472e1c77089e2022-12-21T21:21:32ZengBMCBMC Microbiology1471-21802012-08-0112118010.1186/1471-2180-12-180Formation and characterization of non-growth states in <it>Clostridium thermocellum</it>: spores and L-formsMearls Elizabeth BIzquierdo Javier ALynd Lee R<p>Abstract</p> <p>Background</p> <p><it>Clostridium thermocellum</it> is an anaerobic thermophilic bacterium that exhibits high levels of cellulose solublization and produces ethanol as an end product of its metabolism. Using cellulosic biomass as a feedstock for fuel production is an attractive prospect, however, growth arrest can negatively impact ethanol production by fermentative microorganisms such as <it>C. thermocellum</it>. Understanding conditions that lead to non-growth states in <it>C. thermocellum </it>can positively influence process design and culturing conditions in order to optimize ethanol production in an industrial setting.</p> <p>Results</p> <p>We report here that <it>Clostridium thermocellum</it> ATCC 27405 enters non-growth states in response to specific growth conditions. Non-growth states include the formation of spores and a L-form-like state in which the cells cease to grow or produce the normal end products of metabolism. Unlike other sporulating organisms, we did not observe sporulation of <it>C. thermocellum</it> in low carbon or nitrogen environments. However, sporulation did occur in response to transfers between soluble and insoluble substrates, resulting in approximately 7% mature spores. Exposure to oxygen caused a similar sporulation response. Starvation conditions during continuous culture did not result in spore formation, but caused the majority of cells to transition to a L-form state. Both spores and L-forms were determined to be viable. Spores exhibited enhanced survival in response to high temperature and prolonged storage compared to L-forms and vegetative cells. However, L-forms exhibited faster recovery compared to both spores and stationary phase cells when cultured in rich media.</p> <p>Conclusions</p> <p>Both spores and L-forms cease to produce ethanol, but provide other advantages for <it>C. thermocellum</it> including enhanced survival for spores and faster recovery for L-forms. Understanding the conditions that give rise to these two different non-growth states, and the implications that each has for enabling or enhancing <it>C. thermocellum</it> survival may promote the efficient cultivation of this organism and aid in its development as an industrial microorganism.</p>http://www.biomedcentral.com/1471-2180/12/180 |
| spellingShingle | Mearls Elizabeth B Izquierdo Javier A Lynd Lee R Formation and characterization of non-growth states in <it>Clostridium thermocellum</it>: spores and L-forms BMC Microbiology |
| title | Formation and characterization of non-growth states in <it>Clostridium thermocellum</it>: spores and L-forms |
| title_full | Formation and characterization of non-growth states in <it>Clostridium thermocellum</it>: spores and L-forms |
| title_fullStr | Formation and characterization of non-growth states in <it>Clostridium thermocellum</it>: spores and L-forms |
| title_full_unstemmed | Formation and characterization of non-growth states in <it>Clostridium thermocellum</it>: spores and L-forms |
| title_short | Formation and characterization of non-growth states in <it>Clostridium thermocellum</it>: spores and L-forms |
| title_sort | formation and characterization of non growth states in it clostridium thermocellum it spores and l forms |
| url | http://www.biomedcentral.com/1471-2180/12/180 |
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