Chemistry: molecular biology and microbiology – Process of utilizing an enzyme or micro-organism to destroy... – Resolution of optical isomers or purification of organic...
Reexamination Certificate
2001-12-20
2004-04-27
Saucier, Sandra E. (Department: 1651)
Chemistry: molecular biology and microbiology
Process of utilizing an enzyme or micro-organism to destroy...
Resolution of optical isomers or purification of organic...
C435S253300
Reexamination Certificate
active
06727088
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a process for preparation of (R)-1,2-propanediol from racemic 1,2-propanediol, using a microorganism which has ability to assimilate (S)-1,2-propanediol as a single carbon source.
(R)-1,2-propanediol prepared by the present invention is very important and useful as an intermediate in preparing optically active compounds, such as pharmaceuticals, agrochemicals and physiologically active compounds.
PRIOR ART
In regard to a chemical method for preparation of an optically active 1,2-propanediol, a method by reduction of hydroxy acetone using BINAP catalyst by Kitamura et al. (Tetrahedron Lett., 32,4163-4166 (1991)) and a method by asymmetric hydrolysis using Co-Salen catalyst by Jacobsen et al. (Science, 277, 936-938 (1997) are known. But in order to prepare 1,2-propanediol with optically high purity by these methods, expensive chemical catalyst is necessary and therefore, these methods are hardly said to be an industrially economical method.
In regard to a biological method, a method for preparation of (R)-1,2-propanediol by asymmetric reduction of 1-hydroxy-2-propanone and 1-hydroxy-2-butanone using glycerol dehydrogenase is known (Journal of Organic Chemistry, 51, 25-36(1986)).
Further, a method of preparation for optically active 1,2-propanediol by stereoselectively oxidative degradation using resting cells of microorganisms belonging to a genus Pseudomonas strain by Nikaido et al. (Japanese patent publication A 6-30790). According to this method, as mentioned in the example thereof, after separately cultivating a large amount of microorganisms having ability to stereoselectively degrade 1,2-propanediol and changing thus obtained cells into resting cells, the cells must be subjected to the optical resolution.
The present inventors also reported a method of preparing optically active 1,2-diols and halogenohydrines using oxidative dehalogenation enzyme, namely halohydrin dehydro-dehalogenase derived from Alcaligenes sp. DS-S-7G (Tetrahedron: Asymmetry, 5, 239-246 (1994), Japanese patent publication A 7-147993).
However, in the above mentioned biological methods, co-enzyme such as NAD or NADP is necessary and the regeneration (recycling) of it becomes its reaction rate-limiting factor. These methods are not said to be an economical process for preparation of optically active 1,2-propanediol and therefore, the development of a more effective and practical method has been desired.
DETAILED DESCRIPTION OF INVENTION
The object of the present invention is to provide a more economical and technically simpler method of preparing (R)-1,2-propanediol from racemic 1,2-propanediol comparing with the known methods mentioned above.
The present inventors have searched microorganisms having ability to assimilate (S)-1,2-propanediol preferentially and further, to grow by assimilating (S)-1,2-propanediol as a single carbon source. As a result the present inventors have succeeded in isolating the objective microorganisms and have completed the present invention.
Namely, the present invention relates to a process for preparation of (R)-1,2-propanediol which is characterized in cultivating a microorganism belonging to genus Pseudomonas or genus Alcaligenes which has ability to assimilate (S)-1,2-propanediol as a single carbon source, in a culture medium containing racemic 1,2-propanediol as a single carbon source or a complete synthetic medium containing racemic 1,2-propanediol as a single carbon source, assimilating (S)-1,2-propanediol and then isolating the remaining (R)-1,2-propanediol from the culture broth.
The microorganisms used in the present invention (abbreviated as the present microorganisms), for example Pseudomonas sp. DS-SI-5, Pseudomonas nitroreducens DS-S-RP8 and Alcaligenes sp. DS-S-7G have also ability to assimilate (R)-3-halogeno-1,2-propanediol and in case of the assimilation thereof, hydrogen halide of the same amount as (R)-3-halogeno-1,2-propanediol which is assimilated is released (Japanese patent publication B 4-73999, Japanese patent publication A 2001-149090). Thus, the present microorganisms are strains showing stereoselective dehalogenation ability against halogenohydrin compounds.
Furthermore, although Pseudomonas sp. DS-SI-5 has not ability to assimilate 4-chloro-1,3-butanediol, this strain shows stereoselective dehalogenation activity against (S)-4-chloro-1,3-butandiol to produce (S)-hydroxy-&ggr;-butyrolactone (Japanese patent publication A 2001-120296).
Furthermore, Pseudomonas sp. DS-SI-5 does not have ability to assimilate 1,3-propanediol, 3-amino-1,2-propanediol, 1,2-butanediol, 1,2-pentanediol and 1,2-hexanediol.
Moreover, the present inventors have found that the present microorganisms have ability to stereoselectively assimilate (S)-1,2-propanediol, can grow in the complete synthetic medium containing racemic 1,2-propanediol as a single carbon source and makes non-assimilated (R)-1,2-propanediol remain in the culture broth.
ENBODYMENT OF INVENTION
The present invention relates to a process for preparation of (R)-1,2-propanediol from racemic 1,2-propanediol, by preferentially assimilating (S)-1,2-propanediol, using a microorganism belonging to genus Pseudomonas or genus Alcaligenes which has ability to assimilate (S)-1,2-propanediol as a single carbon source, and by isolating remaining (R)-1,2-propanediol from the culture broth.
Illustratively, first the present microorganisms are cultivated in the complete synthetic medium containing racemic 1,2-propanediol or 3-chloro-1,2-propanediol as a single carbon source, inorganic nitrogen compounds such as various ammonium salts or nitrates as nitrogen source and a small amount of metal salt or phosphate, or in a usual nutrient medium containing organic carbon subsatances and nitrogen substances such as a bouillon medium or a peptone medium and inorganic nutrient sources to prepare seed microorganisms.
Then, a small amount of thus obtained culture broth or microorganism is inoculated with a medium containing racemic 1,2-propanediol as a single source (abbreviated as the medium used in the present invention) and the medium is cultivated to isolate remaining (R)-1,2-propanediol from the culture broth.
Namely, by preferentially assimilating (S)-1,2-propanediol from racemic 1,2-propanediol using the present microorganisms, non-assimilated (R)-1,2-propanediol is made remain in the culture broth and is isolated.
The cultivation is preferably carried out at optimum pH and at optimum temperature, for example at pH 4-10, preferably 5-9, at the temperature of 15-50° C., preferably 20-37° C. In case that pH value gradually decreases with progress of the assimilation, it is necessary to adjust pH in the solution to optimum pH by adding an alkaline substance. The solution is preferably controlled in optimum pH range by using a substance which can be usually used as an acid-neutralizing agent, such as an aqueous alkali carbonate solution such as a calcium carbonate solution, a sodium carbonate solution, a potassium carbonate solution, or an ammonium carbonate solution, an aqueous alkaline hydroxide solution such as a sodium hydroxide solution, a potassium hydroxide solution or a calcium hydroxide solution, or an aqueous ammonia solution.
The concentration of the substrate, namely racemic 1,2-propanediol as carbon source in the medium is preferably 1-15% (v/v), and the substrate may be added at once in the initial stage or in several times.
The cultivation is usually aerobically carried out under stirring or agitation, or under aerobical agitating-cultivation, and the cultivation time depends on the substrate-concentration and other cultural condition, but is preferably completed in 24-120 hours.
When the remaining amount of the substrate, namely racemic 1,2-propanediol becomes 50% comparing with the initial concentration of the substrate by gas chromatography etc., the cultivation is preferably quenched, or the end point may be preferably determined with the measurement of optical purity on the optically active compound in the medium. Namely, exactly when (S)-1,2-propanediol in the s
Idogaki Hideaki
Nakagawa Atsushi
Suzuki Toshio
Ueda Miki
Daiso Co. Ltd.
Saucier Sandra E.
Wenderoth , Lind & Ponack, L.L.P.
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