Chemistry: molecular biology and microbiology – Micro-organism – tissue cell culture or enzyme using process... – Preparing compound containing saccharide radical
Reexamination Certificate
1993-08-03
2001-09-04
Lankford, Jr., Leon B. (Department: 1651)
Chemistry: molecular biology and microbiology
Micro-organism, tissue cell culture or enzyme using process...
Preparing compound containing saccharide radical
C435S147000, C435S155000, C435S252000
Reexamination Certificate
active
06284499
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method for producing L-sorbose by using microorganisms and an apparatus for culturing microorganisms suitable for such a method.
BACKGROUND OF THE INVENTION
L-Sorbose is one of the naturally occurring ketohexoses, which is contained in juice of the rowan tree, etc., and it is an important substance as a raw material in vitamin C synthesis. L-Sorbose is produced by fermentation wherein D-sorbitol is oxidized by microorganisms, for example, bacteria of the genus Gluconobacter.
According to a conventional fermentation production of L-sorbose, a yield of conversion of the raw material, D-sorbitol, into L-sorbose is at highest about 93%, and there are formed considerable amounts of by-products such as 5-ketofructose, D-fructose, 2-ketogluconic acid, etc. In order to reduce the raw material cost of vitamin C, it is requested to increase the yield of conversion of D-sorbitol into L-sorbose more than that in a conventional process and to inhibit formation of the above by-products to as little as possible.
In our European Patent Application No. 233050 (A2), there is disclosed that L-sorbose can be produced in a higher yield from D-sorbitol by microbiological oxidation using a microorganism which belongs to the genus Gluconobacter and which is decreased in the ability to grow with D-sorbitol as the single carbon source compared with that of its parent strains.
By the way, when the concentration of D-sorbitol in a culture medium goes up to over about 5% during and after the growth phase of the microorganisms, they are inhibited due to both high concentrations of the substrate (D-sorbitol) and the product (L-sorbose), which results in delay of the rate of oxidation. Accordingly, it is necessary to control the concentration of D-sorbitol below about 5%. However, when the concentration of the substrate is taken as a rate-determining step, there is a problem that the formation of by-products (fructose, 2-ketogluconic acid, etc.) is increased.
In addition, in this type of a production method, sometimes, a culture exhaust gas containing oxygen in a high concentration is recovered by a compressor, and it is circulated and reused in a culture liquid to save resources. In this case, carbon dioxide gas generated by respiration of the microorganisms is accumulated in the exhaust gas and, when the concentration of carbon dioxide gas goes up to over 10%, the growth rate of the microorganisms and the rate of oxidation are strongly inhibited. Accordingly, in a conventional method, there is employed carbon dioxide gas removing means using an adsorbent such as sodium hydroxide, activated charcoal, etc. However, when such means are employed, there are many problems such as increase in the production cost because of necessity of an adsorption column, an adsorbent and the like and further necessity of maintenance thereof.
Japanese Patent Kokoku No. 61-5709 discloses a method and an apparatus for culturing microorganisms such as fungi. In this publication, a gas enriched with oxygen is prepared from air by adsorbing nitrogen therein, and is used to control the partial pressure of carbon dioxide gas in a culture tank as well as to control the concentration of dissolved oxygen in a culture liquid.
OBJECTS OF THE INVENTION
One object of the present invention is to improve a conversion rate of D-sorbitol into L-sorbose in the production of L-sorbose by microbiological oxidation.
Another object of the present invention is to improve a yield of L-sorbose per batch by properly controlling a concentration of D-sorbitol during and after the growth phase to oxidize a high concentration of D-sorbitol into L-sorbose in a short period of time.
Another object of the present invention is to simplify facilities and maintenance thereof in the production of L-sorbose.
Still another object of the present invention is to reduce the production cost of L-sorbose by removing carbon dioxide gas in a culture exhaust gas to be reused without using any adsorbent to control the partial pressure of carbon dioxide gas properly.
These objects as well as other objects and advantages of the present invention will become apparent to those skilled in the art from the following description with reference to the accompanying drawings.
REFERENCES:
patent: 4413058 (1983-11-01), Arcuri et al.
patent: 0092771 (1983-11-01), None
patent: 175607 (1986-03-01), None
patent: 233050 (1987-08-01), None
Slave et al., Chemical Abstracts 100:173185a, 1984.
Zolotarev et al., Chemical Abstracts 88:188179z, 1978.
Yamada et al., Chemical Abstracts 91:106578 p, 1979.
Mori et al., J. Chem. Eng. Japan, vol. 14, No. 1, 1981, pp. 65-70.
Kintaka Kazuhiko
Kishimoto Katsumitsu
Yoshinaga Hiroyuki
BASF - Aktiengesellschaft
Davidson Davidson & Kappel LLC
Lankford , Jr. Leon B.
LandOfFree
Method for producing L-sorbose and apparatus for culturing... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for producing L-sorbose and apparatus for culturing..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for producing L-sorbose and apparatus for culturing... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2513809