Cryogenic Science and Technology
To clarify the behavior of organisms and matter at loe temperature environments
for industrial application
Objectives of Research
In the cryogenic science and technology at HNIRI, we are promoting seeds
and application for industry based on the research in which we have been
investigating to clarify the phenomena and properties exhibiting by life
and matter at low temperature. We aim to be an international Center of
Excellence (COE) that specialize low temperature science and technologies
in near future.
Our low temperature research contains low temperature biotechnology,
functional materials at low temperature and cold energy system. Organisms
living at cold regions such as Hokkaido, Canada and northern part of Europe,
exhibits characteristic function and owns many bio-materials adopted to
low temperature like enzyme. In the low temperature biotechnology, we are
studying the relationship between the function exhibiting at low temperature
and bio-materials from the view points of gene engineering, structural
biology and enzyme chemistry for industrial application. In functional
materials at low temperature, we are intending to promote to apply materials
as high performance and energy materials by using their excellent electrical,
magnetical, optical and crystalographical properties exhibiting at low
temperature. In cold energy system, we are analyzing the mass and heat
transfer at low temperature together with molecular analysis, to realize
the industrial processes such as storage, transport and utilization processes
of cold heat.
Cryogenic science and technology includes many research subject,
such as basic mesurement and control of cryogenic, and crystalline growth
mechanism of ice induced by ice nucleation protein, which usually require
cooperative research in various research fields. HNIRI is promoting those
researches widely and effectively by organizing fundamental technology
and scientific knowledge in each fields.
Low Temperature Biotechnology
To learn the strategy of organisms living in cold
environments
Objectives of the research
Low temperature is a severe environmental condition for organisms. However,
still many organisms are living in cold environments. They have specific
physiological functions to cope with and adapt to low temperature.
Our objectives of this research are to clarify the specific functions
of cold-adapted organisms, to elucidate the adaptation mechanisms, and
to utilize these organisms and functions to our living and industries.
In order to attain these objectives, we isolate useful microorganisms,
animals and plants from cold environments. Then we separate and characterize
specific substances responsible for cold-adaptation. These substances are
cold-active enzymes, cold-shock proteins, antifreeze proteins, ice-nucleation
proteins, unsaturated fatty acids in membrane, etc.
Cold-adapted organisms and related specific substances may have future
applications in many technologies, such as waste and wastewater treatment
in cold regions, enzymes for detergents, food processing, bioconversions
under mild conditions, etc.
Biotechnology Using Microorganisms
Application of Useful Cold-Adapted Microorgasnisms for Industries
・Microorganisms Producing Both Polysaccharide and PHB
Psychrotrophic microorganism, Deleya marina, that accumulates poly-β-
hydroxybutyrate (PHB) in the cells and produces polysaccharide in the medium
was isolated from a nursery tank used for the forced cultivation of kelp.
It will be quite useful for production of these substances because cost-effective
medium and wide temperature range are available for the cultivation.
| Electron microphotograph of microorganism producing both
polysaccharide and PHB (Deleya marina) |
|
PHB (Left) and polysaccharide (right) obtained from Deleya
marina |
・A bacterium exhibiting extraordinarily high catalase activity
A bacterium, Vibrio rumoiensis S-1., exhibiting extraordinarily
high catalase activity was isolated from a drain pool of a plant in Hokkaido.
The catalase activity of the isolate is much greater than that of ordinary
microorganisms. Application of newly isolated bacterium will provide an
effective mean of decomposing H2O2 contained in industrial
waste such as that produced in the semiconductor and food industries.
・Production of Polyunsaturated Fatty Acids by Bacteria
Polyunsaturated fatty acids (PUFA) have unique biological activities, such
as prevention of blood platelet aggregation, and are used as medicine and
additives of healthy foods. PUFAs are extracted mostly from
fish oil, but they are originally produced by microorganisms, mainly
by psychrophilic and psychrotrophic microorganisms. Therefore, these
microorganisms would be the sources of DHA /EPA production in the future.
We have succeeded in the cloning of gene clusters responsible for shyntheses
of DHA and EPA in bacteria.
In addition, we found that culture broth prepared from the extract
of fish processing wastes stimulated the bacterial growth and increased
in PUFA contents in bacteria.
Structural Biology
To clarify function of a protein on a structural basis
・Structure-Function Relationship
Organisms living in cold environment produce some proteins which exhibit
special functions as a result of cold-adaptation. The ice-nucleation protein
(INP) and antifreeze protein (AFP) are extra members of such cold-adapted
proteins, the former has been thought to function as an active core producing
ice crystal effectively and the latter to interact complementary with the
prism plane of ice crystal so as to depress the freezing pointy non-colligatively.
Because of such unique functions, INP and AFP have been regarded to possess
high potential for industrial applications (ex. artificial rain). However,
the detailed molecular basis of these functions has not been provided so
that it does not lead to a new material production.
Our group employ multinuclear multidimensional NMR spectroscopy to provide
the molecular basis of the functions of INP and AFP. Recently, we have
succeeded to elucidate a local conformation of INP named "hairpin-loop"
(right top figure), which is supposed to repeat tandemly to construct overall
structure. In addition, we have determined the structure of the N-terminal
globular domain with a linker portion (denoted RD3Nl) of TypeIII AFP dimer,
in which the ice-binding site of the two domains are supposed to bind to
the ice surface simultaneously. All these structural basis will lead to
the future industrial applications.
|
A model structure of an antifreeze protein dimer named RD3
|
|
A possible local conformation of ice-nucleation protein.
|
Superpositions of NMR structure of antifreeze protein RD3Nl
|
Biotechnology and Molecular Biology
Cold-Active Enzymes and Genes Related to Cold Adaptation, Their Funtions
and Production.
・Screening and Utilization of Cold-Active Enzymes
Enzymes active at a low temperature have been isolated from cold-adapted
microorganisms and characterized. Isolation of their genes is in process
in order to improve their enzymatic activity and stability by genetic engineering.
Some cold-adapted microorganisms producing a cold-active protease or
a lipase, were isolated from soil and sea water in cold environments. These
cold-active enzymes would have the advantage of high catalytic activity
at a low temperature and thus be useful in food and chemical industries;
i.e. as effective detergent additives suitable for washing in cold tap
water.
The enzymes produced by cold-adapted microorganisms
・Isolation of Cold-Inducible Genes
Genes induced by cold have been screened and their function, structure,
and induction mechanism have been elucidated.
The genes corresponding to protein synthesis and unsaturation of
fatty acids, a major component of membranes, have been isolated so far.
This study aims to know survival mechanisms of living species at a low
temperature by analysis of the cold-related genes. The cold-inducible promoters
would be applied for large-scale production of cold-active enzyme and biological
substances.
Industrial
Technology at Low Temperature
Industrial and Energy Applications for Low Temperature Materials
Objectives of the research
Low temperature technologies are currently used in several common industrial
processes such as energy management and food preservation. Many other industrial
applications for cold media are being developed including gas separation,
pulverization of soft material, cooling of super-computers and the so-called
"atom technology" by using cold media such as liquid gas. We have many
cold energy resources such as LNG, ice and snow in cold region and cooling
media made for the purpose of storage of surplus electricity. In this research
area, the priority interests are to develop highly efficient transportation
and storage technologies, and to expand the use of cold energy resources
for energy saving. In order to realize these goals, two main areas for
research are identified as keys, namely, developments of new media having
high latent heats which can retain and transport cold energy with high
energy density, and the elucidation of dynamics which occurs at low temperature
in terms of molecular level. Some new materials show interesting phase
change phenomena under low temperature. These materials may be found as
a new industrial applications through a study of their properties and performances.
We are conducting R & D on a new integrated energy system and
on materials functioning at low temperature including the use of gas hydrates,
to create a new industrial technology.
Functional Material at Low Temperature, "Gas
Hydrate"
・Engineering Applications of Gas Hydrates
Methane gas is an important clean energy. A huge amount of methane
was discovered as gas hydrates in the word including sea areas around Japan.
Gas hydrates are also studied in a deep sea disposal of carbon dioxide
for suppressing the global warming. Gas hydrates have very interesting
properties; high gas concentration, large latent heat, and so on. We are
studying engineering applications as well as fundamental properties of
gas hydrates.
A polarizing microscopic photograph showing methane hydrates enclosed
in ice. The decomposition of methane hydrates is suppressed by ice even
at an atmospheric pressure.
Studies on Cold Energy Processes
Studies on Energy Transportation, Storage and Relating Processes at Low
Temperature
・Studies on Novel Phase Change Materials for Cold Energy Storage
Fundamental properties of gas hydrates are studied: rates and mechanisms
of formation and decomposition processes, thermal properties, and so on.
These studies are carried out to develop new technologies of natural gas
storage and transportation, and cold thermal energy storage. Also, studies
on cold energy using micro cupsule are carrying out.
Cooling test unit using gas hydrate
・Studies on the relaxation time of molecular at low temperature
A crushing prosess is widely used in industries, and there are some materials
having difficulty for crushing. However, it become easier to crush at low
temperature conditions. This study aims to determine optimum temperature
condition by observing motions of molecular.
・Humidity Controling Technology Under Freezing Point for Long Term Storage
of Fresh Vegetables
The humidity controlling technology under freezing point will be one of
key technologies for long term storage of fresh vegetables. Water supplying
with small droplet to the atmosphere of storage room promises an effective
humidity controlling technology without ice deposition problem. This project
is doing under cooperation with universities and companies in Hokkaido.
Besides, investigations on cold energy storage and efficient energy conversion
is performed on.
Testing Shed for Long Term Storage of Vegitables
Research on Low Temperature Materials
・Synthesis of photo-functional polymers by ring-opening polymerization
induced by metal nano-particles
We have developed a synthesis method of patterned polymer thin film by
ring-opening polymerization of cyclic silicon compound induced by metal
nano-particles. We have been studying photo-functional polymers synthesized
by this method.
・Research on magnetoresistance materials
The magnetoresistance (MR) properties of sputtered Co-Ag thin films
have been studied. The evolution of the MR properties and the phase
separation in this sputtered Co-Ag system were investigated in relation
to the annealing condition and the RE-doping. Experimental results
showed that the doping of either Ce, Tb or Sm enhanced the MR response
of the Co-Ag films, while Nd depressed the response.
・Research on thermoelectric semiconductors
Thermoelectric energy conversion can convert a thermal energy to electrical
one or vice vase, by using semiconductors. Development of new and high
performance thermoelectric semiconductors can be attributed to a waste
heat recovery field and so on. In this study, we have focused on the material
research for the low temperature application below 300 K. We have discovered
that the Ag-Te-Se compound is one of the new high ZT materials. We have
studied the application the clathrate compounds to thermoelectrics also.
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