Chemistry: molecular biology and microbiology – Micro-organism – tissue cell culture or enzyme using process... – Preparing oxygen-containing organic compound
Reexamination Certificate
2000-04-12
2001-10-16
Prats, Francisco (Department: 1651)
Chemistry: molecular biology and microbiology
Micro-organism, tissue cell culture or enzyme using process...
Preparing oxygen-containing organic compound
C435S157000, C435S155000, C435S105000, C435S072000
Reexamination Certificate
active
06303353
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a method of producing xylitol. Xylitol is useful in the field of food, medicines, and the like.
BACKGROUND ART
The demand for xylitol, which is a sugar alcohol existing in nature, is expected to increase from now on. Xylitol has a lower caloric value than that of sucrose but is sweet as comparable to sucrose. Thus, it is promising as a low caloric sweetener. Furthermore, xylitol is anticariogenic and can be a dental caries-preventing sweetener. Since xylitol does not raise the blood glucose level, it has been used for infusion liquids for treating diabetes.
At present, xylitol is mainly produced in an industrial scale by hydrogenation of D-xylose as described in U.S. Pat. No. 4,008,825. The raw material, D-xylose, can be obtained by hydrolyzing a starting material such as hardwoods, straws, ear stems of corns, crusts of oats, or the other plant-derived materials rich in xylan.
However, D-xylose that is obtained by hydrolyzing the plant materials is disadvantageously expensive because of the high production cost. For example, the yield of the plant material-hydrolyzed product is low, which makes purity of produced D-xylitol low. After the hydrolysis, it is thus necessary to remove the acid used in the hydrolysis and the pigment by the ion exchange treatment. Furthermore, D-xylitol is crystallized to remove other hemicelluloses. Further purification is required to obtain D-xylose that can be used for food. The ion exchange treatment and crystallization results in an increase of the production cost.
In order to solve the above problems, a method of producing xylitol that uses a readily available starting material and that produces a reduced amount of waste matters has been desired. For example, a method of producing xylitol using pentitol as a starting material has been developed. One of the readily available pentitols is D-arabitol that can be produced using yeast (
Can. J. Microbiol
. 31, 1985, 467-471
, J. Gen. Microbiol
. 139, 1993, 1047-1054).
Several methods have been developed for producing xylitol using D-arabitol as a starting material.
Applied Microbiology
, 18, 1969, 1031-1035 reported a method that comprises producing D-arabitol from glucose by fermentation using
Debaryomyces hansenii
ATCC20121, converting D-arabitol thus obtained to D-xylulose using
Acetobacter suboxydans
, and converting D-xylulose to xylitol using
Candida guilliermondii
var. Soya.
EP-A-403392 (applicant: Roquette Freres) and EP-A-421882(applicant: Roquette Freres) each discloses a method which comprises producing D-arabitol by fermentation using an osmotic pressure-resistant yeast, converting D-arabitol thus produced to D-xylulose using a microorganism belonging to the genus Acetobacter, Gluconobacter, or Klebsiella, reacting xylulose thus obtained with glucose (xylose) isomerase to produce a mixture of xylose and xylulose, and converting the thus-formed xylose/xylulose to xylitol by hydrogenation. These publications also disclose a method of preliminarily concentrating xylose in the xylose/xylulose mixture and converting concentrated xylose to xylitol by hydrogenation.
The above-described method of producing xylitol using the D-arabitol above as a starting material enables a high yield production of xylitol. However, it is disadvantageous in requiring plural reaction steps, which makes the process complicated. Thus, the method is not economically satisfactory.
DISCLOSURE OF THE INVENTION
An object of the present invention is to provide a method of producing xylitol using D-arabitol as a starting material and the method achieved by a simple process.
As a result of intensive investigation, the present inventors found microorganisms having the activity to convert D-arabitol to xylitol directly, thereby completing the present invention and solving the above problems.
The present invention relates to a method of producing xylitol comprising the steps of contacting D-arabitol with a microorganism that belongs to the genus Gluconobacter or Acetobacter and is capable of converting D-arabitol to xylitol, and recovering xylitol thus produced.
The present invention also relates to a method of producing xylitol comprising the steps of contacting D-arabitol with a microorganism that belongs to
Gluconobacter suboxydans, Gluconobacter oxydans
, or
Acetobacter xylinum
and is capable of converting D-arabitol to xylitol, and recovering xylitol thus produced.
The present invention further relates to a method of producing xylitol comprising the steps of contacting D-arabitol with a microorganism that belongs to the genus Achromobacter, Agrobacterium, Arthrobacter, Azotobacter, Brevibacterium, Corynebacterium, Erwinia, Flavobacterium, Micrococcus, Nocardia, Planococcus, Pseudomonas, or Rhodococcus and is capable of converting D-arabitol to xylitol, and recovering xylitol thus produced.
Furthermore, the present invention relates to a method of producing xylitol comprising the steps of contacting D-arabitol with a microorganism that belongs to
Achromobacter viscosus, Agrobacterium tumefaciens, Agrobacterium radiobacter, Arthrobacter paraffineus, Arthrobacter hydrocarboglutamicus, Azotobacter indicus, Brevibacterium ketoglutamicum, Corynebacterium fasciens, Erwinia amylovora, Flavobacterium peregrinum, Flavobacterium fucatum
, Micrococcus sp. CCM825
, Nocardia opaca, Planococcus eucinatus, Pseudomonas synxantha
, or
Rhodococcus erythropolis
and is capable of converting D-arabitol to xylitol, and recovering xylitol thus produced.
Moreover, the present invention relates to a method of producing xylitol comprising the steps of contacting D-arabitol with a microorganism that belongs to the genus Morganella, Actinomadura, Actinomyces, or Streptomyces and is capable of converting D-arabitol to xylitol, and recovering xylitol thus produced.
In addition, the present invention relates to a method of producing xylitol comprising the steps of contacting D-arabitol with a microorganism that belongs to
Morganella morganii, Actinomadura madurae, Actinomyces violaceochromogenes, Streptomyces coelicolor, Streptomyces flavelus, Streptomyces griseolus, Streptomyces lividans, Streptomyces olivaceus, Streptomyces tanashiensis, Streptomyces virginiae, Streptomyces antibioticus, Streptomyces cacaoi
, or
Streptomyces lavendulae
and is capable of converting D-arabitol to xylitol, and recovering xylitol thus produced.
The present invention will be described in detail below.
The microorganisms used in the present invention belong to the genus Gluconobacter, Acetobacter, Achromobacter, Agrobacterium, Arthrobacter, Azotobacter, Brevibacterium, Corynebacterium, Erwinia, Flavobacterium, Micrococcus, Nocardia, Planococcus, Pseudomonas, Rhodococcus, Morganella, Actinomadura, Actinomyces, or Streptomyces and are capable of converting D-arabitol to xylitol.
Examples of the above-described microorganisms include
Gluconobacter suboxydans, Gluconobacter oxydans, Acetobacter xylinum, Achromobacter viscosus, Agrobacterium tumefaciens, Agrobacterium radiobacter, Arthrobacter paraffineus, Arthrobacter hydrocarboglutamicus, Azotobacter indicus, Brevibacterium ketoglutamicum, Corynebacterium fasciens, Erwinia amylovora, Flavobacterium peregrinuim, Flavobacterium fucatum
, Micrococcus sp. CCM825
, Nocardia opaca, Planococcus eucinatus, Pseudomonas synxantha, Rhodococcus erythropolis, Morganella morganii, Actinomadura madurae, Actinomyces violaceochromogenes, Streptomyces coelicolor, Streptomyces flavelus, Streptomyces griseolus, Streptomyces lividans, Streptomyces olivaceus, Streptomyces tanashiensis, Streptomyces virginiae, Streptomyces antibioticus, Streptomyces cacaoi
, and
Streptomyces lavendulae.
Specific strains of the microorganisms used in the invention include the following:
Gluconobacter suboxydans
NRRLB-755;
Gluconobacter oxydans
ATCC621;
Gluconobacter oxydans
IAM1842;
Gluconobacter oxydans IAM
1839;
Acetobacter xylinum
ATCC14851;
Achromobacter viscosus
ATCC12448;
Agrobacterium tumefaciens
ATCC2778;
Agrobacterium radiobacter
ATCC4718;
Arthrobacter paraffineus
ATCC15590;
Arthroba
Hashiguchi Ken-ichi
Mihara Yasuhiro
Sugiyama Masakazu
Suzuki Shunichi
Yokozeki Kenzo
Ajinomoto Co. Inc.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Prats Francisco
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