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Caloramator Boliviensis, a New Thermoanaerobe with Interesting Metabolic Properties

Crespo, Carla LU (2012)
Abstract (Swedish)
Popular Abstract in English

Among the forms of life found in extreme environments (e.g. high temperatures ‘thermo’ and oxygen deficient ‘anaerobe’), the thermoanaerobic bacteria emerge as a highly evolved and interesting subject of study. Bacteria living as microbial mats in decaying plant material possess a great potential not only to degrade complex biomass but also to produce special chemicals. In the present study we discovered a new bacterium ‘Caloramator boliviensis’ that lives at high temperature in decaying wood. More interestingly, C. boliviensis digests the main components of plant biomass and produces bioethanol and other valuable chemicals.

By operating at high temperatures, the ethanol production... (More)
Popular Abstract in English

Among the forms of life found in extreme environments (e.g. high temperatures ‘thermo’ and oxygen deficient ‘anaerobe’), the thermoanaerobic bacteria emerge as a highly evolved and interesting subject of study. Bacteria living as microbial mats in decaying plant material possess a great potential not only to degrade complex biomass but also to produce special chemicals. In the present study we discovered a new bacterium ‘Caloramator boliviensis’ that lives at high temperature in decaying wood. More interestingly, C. boliviensis digests the main components of plant biomass and produces bioethanol and other valuable chemicals.

By operating at high temperatures, the ethanol production technology becomes simplified thereby contributing towards a cost effective process. In addition, the conversion of plant biomass into ethanol is one of the hopes for solving the energy crisis in the future.



The proposal of using thermoanaerobic bacteria for industrial ethanol production dates from long ago. Therefore, some bacteria related to C. boliviensis are under study. Ethanol production by the novel C. boliviensis was evaluated at laboratory scale and high ethanol yields were obtained using various sugars. The ability of C. boliviensis to produce ethanol lies in its genetic information that commands processes to occur inside the cell. Understanding those processes, their balance and regulation allows us to determine the real potential of C. boliviensis to produce ethanol. It is important to mention that in nature, no microorganisms have been identified that possess all of the characteristics necessary for the optimal ethanol production, so one may have to genetically engineer C. boliviensis for this purpose. Genetic engineering of C. boliviensis to maximize ethanol production leads to additional research. However, a solid basis for understanding the natural occurring ethanol formation by C. boliviensis is settled and as a result of the present study future genetic engineering of C. boliviensis is prospected. (Less)
Abstract
A novel ethanol-producing thermoanaerobe Caloramator boliviensis 45BT (=DSM 22065T, =CCUG 57396T) was isolated from a hot spring of the Bolivian highlands. C. boliviensis possesses the ability to utilize a wide range of substrates and can efficiently convert hexoses and pentoses into ethanol with concomitant production of acetate, carbon dioxide and hydrogen as by-products of fermentation. However, under different cultivation conditions C. boliviensis yields lactate, butyrate, propanediol, succinate and formate. A branched metabolism and an interesting catabolic flexibility are characteristics of C. boliviensis. An usual mixed acid fermentation could be directed to a glucose-based acetogenic, homolactic or homoethanolic metabolism. In... (More)
A novel ethanol-producing thermoanaerobe Caloramator boliviensis 45BT (=DSM 22065T, =CCUG 57396T) was isolated from a hot spring of the Bolivian highlands. C. boliviensis possesses the ability to utilize a wide range of substrates and can efficiently convert hexoses and pentoses into ethanol with concomitant production of acetate, carbon dioxide and hydrogen as by-products of fermentation. However, under different cultivation conditions C. boliviensis yields lactate, butyrate, propanediol, succinate and formate. A branched metabolism and an interesting catabolic flexibility are characteristics of C. boliviensis. An usual mixed acid fermentation could be directed to a glucose-based acetogenic, homolactic or homoethanolic metabolism. In addition, redistribution of end-products led to a lactate-based butyrate formation described for the first time for a member of the Caloramator genus. The flexibility to switch between metabolic pathways in order to balance the electron and carbon flow makes C. boliviensis an interesting candidate for metabolic engineering to maximize ethanol productivity.



Based on the interesting characteristics described above, the fermentative metabolism of C. boliviensis was also evaluated at genome level. The draft genome of C. boliviensis (3.2 Mb, G+C 32 mole%) encompasses 2896 predicted protein-coding genes, the larger number of genes match to the transport and metabolism of amino acids and carbohydrates. Although, C. boliviensis displays potential for producing ethanol, before developing a full process, limitations such as substrate and product concentrations, nutrients requirement, reaction rates and metabolic shifts must be overcome. Nevertheless, the genome functional annotation provides a platform for future metabolic engineering strategies to improve ethanol titres and productivities and to increase the understanding of the physiology of C. boliviensis. (Less)
Please use this url to cite or link to this publication:
author
supervisor
opponent
  • Prof. Enfors, Sven-Olof, Department of Biotechnology, Royal Institute of Technology, Stockholm, Sweden
organization
publishing date
type
Thesis
publication status
published
subject
keywords
Caloramator boliviensis, catabolic flexibility, ethanol production, butyrate-based lactate, wide substrate utilization range, metabolic shift, carbon and electron balance, functional genome annotation
pages
142 pages
publisher
Biotechnology, Lund University
defense location
Lecture hall B, Center of Chemistry and Chemical Engineering, Getingevägen 60, Lund University, Faculty of Engineering
defense date
2012-10-31 10:30
ISBN
978-91-89627-85-7
language
English
LU publication?
yes
id
bd41cb9e-b588-4c33-ab34-d129803bb021 (old id 3125425)
date added to LUP
2012-10-10 11:10:32
date last changed
2016-09-19 08:45:15
@phdthesis{bd41cb9e-b588-4c33-ab34-d129803bb021,
  abstract     = {A novel ethanol-producing thermoanaerobe Caloramator boliviensis 45BT (=DSM 22065T, =CCUG 57396T) was isolated from a hot spring of the Bolivian highlands. C. boliviensis possesses the ability to utilize a wide range of substrates and can efficiently convert hexoses and pentoses into ethanol with concomitant production of acetate, carbon dioxide and hydrogen as by-products of fermentation. However, under different cultivation conditions C. boliviensis yields lactate, butyrate, propanediol, succinate and formate. A branched metabolism and an interesting catabolic flexibility are characteristics of C. boliviensis. An usual mixed acid fermentation could be directed to a glucose-based acetogenic, homolactic or homoethanolic metabolism. In addition, redistribution of end-products led to a lactate-based butyrate formation described for the first time for a member of the Caloramator genus. The flexibility to switch between metabolic pathways in order to balance the electron and carbon flow makes C. boliviensis an interesting candidate for metabolic engineering to maximize ethanol productivity. <br/><br>
<br/><br>
Based on the interesting characteristics described above, the fermentative metabolism of C. boliviensis was also evaluated at genome level. The draft genome of C. boliviensis (3.2 Mb, G+C 32 mole%) encompasses 2896 predicted protein-coding genes, the larger number of genes match to the transport and metabolism of amino acids and carbohydrates. Although, C. boliviensis displays potential for producing ethanol, before developing a full process, limitations such as substrate and product concentrations, nutrients requirement, reaction rates and metabolic shifts must be overcome. Nevertheless, the genome functional annotation provides a platform for future metabolic engineering strategies to improve ethanol titres and productivities and to increase the understanding of the physiology of C. boliviensis.},
  author       = {Crespo, Carla},
  isbn         = {978-91-89627-85-7},
  keyword      = {Caloramator boliviensis,catabolic flexibility,ethanol production,butyrate-based lactate,wide substrate utilization range,metabolic shift,carbon and electron balance,functional genome annotation},
  language     = {eng},
  pages        = {142},
  publisher    = {Biotechnology, Lund University},
  school       = {Lund University},
  title        = {Caloramator Boliviensis, a New Thermoanaerobe with Interesting Metabolic Properties},
  year         = {2012},
}