Investigation of growth modes of the lithoautotrophic bacterium Cupriavidus necator
(2018) KMBM01 20181Applied Microbiology
Biotechnology
- Abstract
- The microorganism Cupriavidus necator is a very interesting bacterium that has been established as a model microorganism for its capability to produce polyhydroxyalkanoates, more specifically polyhydroxybutyrate (PHB), a potential precursor/raw material for bioplastics. Lately, the scientific community has raised interest in the chemolithoautotrophic nature of C. necator as it can be grown using CO2 and H2 as its only carbon and energy sources, respectively. Alternatively, it can also be grown under organoautotrophic conditions, where formic acid is used as substrate that is further metabolized in the cell to obtain CO2 and reduced NADPH. The organoautotrophic growth mode is presumably similar to lithoautotrophic growth, as both modes only... (More)
- The microorganism Cupriavidus necator is a very interesting bacterium that has been established as a model microorganism for its capability to produce polyhydroxyalkanoates, more specifically polyhydroxybutyrate (PHB), a potential precursor/raw material for bioplastics. Lately, the scientific community has raised interest in the chemolithoautotrophic nature of C. necator as it can be grown using CO2 and H2 as its only carbon and energy sources, respectively. Alternatively, it can also be grown under organoautotrophic conditions, where formic acid is used as substrate that is further metabolized in the cell to obtain CO2 and reduced NADPH. The organoautotrophic growth mode is presumably similar to lithoautotrophic growth, as both modes only differ in the initial step of substrate assimilation. An initial attempt to characterize growth under organoautotrophic conditions was performed and it was observed that the biomass yield was almost three times lower than using fructose as substrate for heterotrophic mode. Furthermore, growth under anaerobic conditions was explored as an alternative to avoid the potential explosion risk from mixtures of hydrogen and oxygen. It was found that respiration, either using oxygen or nitrate as electron acceptor, is needed for ATP production in C. necator and thus to support growth. To facilitate growth and reoxidation of NADH also under anaerobic conditions a new strain was generated in which the ethanol fermentation pathway was introduced. A preliminary characterization of the fermentative capacity of this strain showed that no ethanol was produced when grown organoautotrophically. (Less)
- Popular Abstract
- Exploring the use of a bacteria to reduce atmospheric CO2 levels
The emission of greenhouse gases such as carbon dioxide (CO2) and methane (CH4) that trap heat in the atmosphere, has escalated in the last 50 years. This has led to a temperature increase on Earth by 1 °C since 1880 and it is believed to increase further if these gas emissions are not reduced. One of the main sources for heat-trapping pollution is the burning of fossil fuels for electricity and alternatives are therefore needed in the near future. Another possibility to reduce atmospheric CO2 is to capture the gas and convert it to sustainable products. But the question on everyone’s mind is, can microorganisms help us reduce the impact on global warming caused by human... (More) - Exploring the use of a bacteria to reduce atmospheric CO2 levels
The emission of greenhouse gases such as carbon dioxide (CO2) and methane (CH4) that trap heat in the atmosphere, has escalated in the last 50 years. This has led to a temperature increase on Earth by 1 °C since 1880 and it is believed to increase further if these gas emissions are not reduced. One of the main sources for heat-trapping pollution is the burning of fossil fuels for electricity and alternatives are therefore needed in the near future. Another possibility to reduce atmospheric CO2 is to capture the gas and convert it to sustainable products. But the question on everyone’s mind is, can microorganisms help us reduce the impact on global warming caused by human activities? The answer is yes.
In this project, the bacteria Cupriavidus necator has been studied. This microorganism is capable of consuming atmospheric carbon dioxide when hydrogen is also supplied. Thus, the cultivation of this microorganism could help reducing the high levels of carbon dioxide present in the atmosphere nowadays. Furthermore, this awesome microorganism can naturally produce a polymer that can be used as raw material to produce bioplastics. Plastics are another big problem in today’s society since every year, 8 million metric tons of plastic end up in our oceans. If bioplastics replaced traditional plastics, the use of petroleum would be reduced and most importantly less plastic waste would be produced since certain bioplastics can be biodegraded in nature. Can you imagine using carbon dioxide to produce bioplastics? That is precisely the potential for this microorganism!
To enable growth on carbon dioxide as the sole carbon source, C. necator also requires oxygen and hydrogen. Unfortunately, it is potentially dangerous to carry out experiments with these gases since mixing of hydrogen and oxygen in the wrong proportions can result in an explosion. To avoid this, safer alternatives using formic acid that can be taken up by the bacteria and converted to CO2 inside the cell have been explored in this project both under aerobic and anaerobic conditions using oxygen and nitrate respiration, respectively. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/8950772
- author
- Perruca Foncillas, Raquel LU
- supervisor
- organization
- alternative title
- Karakterisering av den litoautotrofa bakterien Cupriavidus necator under olika tillväxtförhållanden
- course
- KMBM01 20181
- year
- 2018
- type
- H2 - Master's Degree (Two Years)
- subject
- keywords
- applied microbiology, teknisk mikrobiologi
- language
- English
- id
- 8950772
- date added to LUP
- 2018-06-18 15:46:46
- date last changed
- 2018-06-18 15:46:46
@misc{8950772,
abstract = {{The microorganism Cupriavidus necator is a very interesting bacterium that has been established as a model microorganism for its capability to produce polyhydroxyalkanoates, more specifically polyhydroxybutyrate (PHB), a potential precursor/raw material for bioplastics. Lately, the scientific community has raised interest in the chemolithoautotrophic nature of C. necator as it can be grown using CO2 and H2 as its only carbon and energy sources, respectively. Alternatively, it can also be grown under organoautotrophic conditions, where formic acid is used as substrate that is further metabolized in the cell to obtain CO2 and reduced NADPH. The organoautotrophic growth mode is presumably similar to lithoautotrophic growth, as both modes only differ in the initial step of substrate assimilation. An initial attempt to characterize growth under organoautotrophic conditions was performed and it was observed that the biomass yield was almost three times lower than using fructose as substrate for heterotrophic mode. Furthermore, growth under anaerobic conditions was explored as an alternative to avoid the potential explosion risk from mixtures of hydrogen and oxygen. It was found that respiration, either using oxygen or nitrate as electron acceptor, is needed for ATP production in C. necator and thus to support growth. To facilitate growth and reoxidation of NADH also under anaerobic conditions a new strain was generated in which the ethanol fermentation pathway was introduced. A preliminary characterization of the fermentative capacity of this strain showed that no ethanol was produced when grown organoautotrophically.}},
author = {{Perruca Foncillas, Raquel}},
language = {{eng}},
note = {{Student Paper}},
title = {{Investigation of growth modes of the lithoautotrophic bacterium Cupriavidus necator}},
year = {{2018}},
}