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Rhodothermus marinus - A New Potential Biorefinery Organism

Mukti, Israt Jahan (2018) MOBN03 20172
Degree Projects in Molecular Biology
Popular Abstract
The amazing Thermophile Rhodothermus marinus

Thermophiles are microorganisms i.e. bacteria and archea that thrive between the temperature 41ºC to 122ºC. As they can grow at extremely high temperatures, they are also known as extremophiles. Mostly, they are found on geothermally heated places like hot springs or deep sea hydrothermal vents.

Rhodothermus marinus is a thermophilic bacterium, interesting for its potential high value products (enzymes, carotenoids and exopolysaccharides) and was isolated from a submarine hotspring at 2-4 m depth in Isafjardardjup, NW Iceland. The species is a Gram-negative, rod shaped, oxygen and sodium chloride demanding reddish bacterium which grows optimally at 65˚C. The bacterium is able to utilize... (More)
The amazing Thermophile Rhodothermus marinus

Thermophiles are microorganisms i.e. bacteria and archea that thrive between the temperature 41ºC to 122ºC. As they can grow at extremely high temperatures, they are also known as extremophiles. Mostly, they are found on geothermally heated places like hot springs or deep sea hydrothermal vents.

Rhodothermus marinus is a thermophilic bacterium, interesting for its potential high value products (enzymes, carotenoids and exopolysaccharides) and was isolated from a submarine hotspring at 2-4 m depth in Isafjardardjup, NW Iceland. The species is a Gram-negative, rod shaped, oxygen and sodium chloride demanding reddish bacterium which grows optimally at 65˚C. The bacterium is able to utilize many complex carbon sources.

The thermophilic bacterium R. marinus is able to use a wide range of sugars (glucose, arabinose, mannose, galactose) and produce an array of complex carbohydrate (polysaccharides) degrading enzymes, which has made it a promising organism. It also produces interesting products, such as extracellular polysaccharides or exopolysaccharides (EPS) and carotenoids (organic red pigments). These capabilities and the robustness as a thermophile attracted the interests of researchers. Even though the organism has gathered interest so far, too little is known about how to cultivate the bacterium, which hampers the development. The aim of this study was to develop a cultivation technology for R. marinus strain MAT 493, thereby developing its potential in biorefinery applications. This is done by evaluating obtained cell mass and production of the two target products i.e. EPSs and/or carotenoids as success indicators.

Bacteria need a wide range of growth factors for their growth. In this study, a defined growth medium was optimized without any complex ingredients like yeast extract or beef extract. The bacterium was able to grow with a doubling time of 2.83 h in the optimized defined medium (ODM) containing 0.5 % glucose. The maximum amount of EPS was produced during fed batch cultivation and was hetero-polysaccharide polymers composed of arabinose, glucose, mannose and xylose, with one additional detected monosaccharide that remains unidentified. The production of EPSs and carotenoids on ODM were both highly correlated with bacterial growth and consumption of supplied sugar.

The ODM and the developed cultivation technology for R. marinus MAT 493 simplifies further study of this bacterium. The findings are also supporting the potential of this bacterium as a successful biorefinery organism.

Master’s Degree Project in Molecular Biology 60 credits 2018
Department of Biology, Lund University

Advisor: Eva Nordberg Karlsson
Professor, Division of Biotechnology, Lund University (Less)
Please use this url to cite or link to this publication:
author
Mukti, Israt Jahan
supervisor
organization
course
MOBN03 20172
year
type
H2 - Master's Degree (Two Years)
subject
language
English
id
8960338
date added to LUP
2018-10-16 14:50:33
date last changed
2018-10-16 14:50:33
@misc{8960338,
  author       = {{Mukti, Israt Jahan}},
  language     = {{eng}},
  note         = {{Student Paper}},
  title        = {{Rhodothermus marinus - A New Potential Biorefinery Organism}},
  year         = {{2018}},
}