A method for preparing xylitol and L-arabinose from liquid xylitol

Abstract

The invention discloses a method for preparing xylitol and L-arabinose from liquid xylitol, comprising the following steps: (1) diluting a xylose mother liquor, adding a nitrogen source and an inorganic salt, sterilizing, and setting aside; (2) inoculating Candida for fermentation, wherein the Candida can decompose other sugars except arabinose; (3) after the fermentation is completed, centrifuging and filtering the fermentation liquid to obtain a supernatant; (4) desalting the supernatant by passing an ion exchange resin; (5) removing pigment from the supernatant, concentrating and crystallizing it, and separating the crystallized material to obtain xylitol crystals and a xylitol mother liquor; (6) separating the obtained xylitol mother liquor by a chromatographic system to obtain a xylitol phase and an L-arabinose phase; (7) concentrating and crystallizing the obtained L-arabinose phase, and separating the crystallized material to obtain L-arabinose crystals and an L-arabinose liquid. The method of the invention can obtain xylitol with a higher yield, and separate high-purity and high-yield L-arabinose from it.

Description

Technical Field

[0001] The invention relates to the field of biotechnology, and in particular to a method for preparing xylitol and L-arabinose from liquid xylitol. Background Art

[0002] L-arabinose, also known as L-arabinose and L-arabinose, has a molecular formula of C5H 10 O5. L-arabinose can be separated and extracted from pectin substances in plant hemicellulose such as corn cobs, corn husks, peels, bagasse, wheat, rice and apple pulp; it is white in appearance and only half as sweet as sucrose; the naturally occurring arabinose in nature is L-arabinose, which is not metabolized by animals, so L-arabinose is a low-calorie monosaccharide. L-arabinose is a reducing sugar with a similar structure and molecular weight to xylitol. It can non-competitively inhibit the absorption of sucrose by the small intestine and is widely used in the fields of weight loss and "three highs". As a functional sugar ingredient, it has been widely used in various health foods and beverages, and has a good market prospect.

[0003] The main methods for preparing L-arabinose include hydrolysis, microbial method, chemical synthesis, etc. Although the process of preparing L-arabinose by hydrolysis is relatively mature, it is neither suitable nor environmentally friendly if it is used to produce food and medicine. The process of producing rare sugars by microbial method has been widely developed and applied due to its mild operating conditions, environmental protection factors, enzyme specificity and high efficiency. However, the xylitol fermentation broth usually obtained by microbial fermentation of hemicellulose plants (corn cobs) has a complex composition. In addition to the main product xylitol, it also contains many other components, and the process of separating L-arabinitol from it is complicated. Therefore, it is of great significance to develop a new method for preparing L-arabinose. Summary of the invention

[0004] The purpose of the present invention is to provide a method for preparing xylitol and L-arabinose from liquid xylitol, which can obtain xylitol with a higher yield and separate high-purity and high-yield L-arabinose, and the method is simple, easy to operate and easy to industrialize.

[0005] To this end, the present invention adopts the following technical solutions:

[0006] The present invention provides a method for preparing xylitol and L-arabinose from liquid xylitol, comprising the following steps:

[0007] (1) diluting the xylose mother liquor, adding a nitrogen source and an inorganic salt, sterilizing, and setting aside;

[0008] (2) inoculating Candida for fermentation, wherein the Candida can decompose sugars other than arabinose;

[0009] (3) After the fermentation is completed, the fermentation broth is centrifuged and filtered to obtain the supernatant;

[0010] (4) desalting the above clear solution through an ion exchange resin;

[0011] (5) removing pigment from the clear liquid, concentrating and crystallizing the clear liquid, and separating the crystallized material to obtain xylitol crystals and xylitol mother liquor;

[0012] (6) separating the obtained xylitol mother liquor through a chromatography system to obtain a xylitol phase and an L-arabinose phase;

[0013] (7) After the obtained L-arabinose phase is concentrated and crystallized, the crystallized material is separated to obtain L-arabinose crystals and L-arabinose liquid.

[0014] Further, the dilution concentration of the xylose mother liquor is 40-200 g / L;

[0015] Preferably, the concentration is 50-180 g / L;

[0016] More preferably, the concentration is 80-150 g / L.

[0017] Furthermore, the nitrogen source is one or more of peptone, yeast extract, urea and (NH4)2SO4.

[0018] Furthermore, the Candida can utilize xylose to produce xylitol.

[0019] Preferably, the desalination method in step (4) may also be ultrafiltration or further ultrafiltration desalination.

[0020] Furthermore, the method for removing pigment in step (5) is activated carbon decolorization, ion exchange resin decolorization, membrane treatment decolorization and flocculation decolorization.

[0021] Preferably, in step (5), secondary pigment removal is performed followed by concentration and crystallization.

[0022] Furthermore, the chromatography system in step (6) is a chromatography system filled with a resin or molecular sieve that has a separation effect on sugars and alcohols.

[0023] Preferably, the chromatographic system in step (6) is a cross-linked sulfonated styrene divinyl benzene cation exchange (PS-DVB) resin, a calcium-type ion exchange resin, or a combination of the two.

[0024] Furthermore, the L-arabinose mother liquor obtained in step (6) is further concentrated and crystallized after chromatographic separation to obtain L-arabinose crystals.

[0025] Furthermore, the L-arabinose phase obtained in step (6) is returned and mixed with the xylitol mother liquor in step (5), and then further concentrated, crystallized, and separated.

[0026] Furthermore, the L-arabinose liquid obtained in step (7) is further concentrated and recrystallized to obtain L-arabinose crystals.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The process route of the invention is simple and easy to operate. By fermenting xylose with Candida, sugars other than L-arabinose are decomposed and converted into xylitol. After removing the components such as bacteria, inorganic salts, pigments, etc., L-arabinose is separated from the xylitol mother liquor by chromatographic separation technology. While recovering xylitol in the xylitol crystal mother liquor, high-value-added L-arabinose in the xylitol mother liquor is extracted, and the produced L-arabinose crystals are of high quality. The method is easy to industrialize, and L-arabinose has good application prospects in the fields of food and medicine, and can generate good economic value. DETAILED DESCRIPTION

[0029] The following is a further detailed description of the claims of the present invention in conjunction with specific implementation methods, but does not constitute any limitation to the present invention. Any limited modifications made by anyone within the scope of protection of the claims of the present invention are still within the scope of protection of the claims of the present invention.

[0030] Example 1

[0031] A method for preparing xylitol and L-arabinose from liquid xylitol comprises the following steps:

[0032] (1) dilute the xylose mother liquor to a concentration of 200 g / L, add 5 g / L peptone and inorganic salts, sterilize and set aside;

[0033] (2) inoculating Candida for fermentation, wherein the Candida can decompose sugars other than arabinose and convert xylose into xylitol, and the Candida is Candida tropicalis KCCM 50091;

[0034] (3) After the fermentation is completed, the fermentation broth is centrifuged and filtered to obtain the supernatant;

[0035] (4) desalting the above clear solution through a calcium-type ion exchange resin;

[0036] (5) treating the clear liquid with a membrane to remove pigments, then concentrating and crystallizing the clear liquid, and separating the crystallized material to obtain xylitol crystals and xylitol mother liquor;

[0037] (6) separating the obtained xylitol mother liquor through a chromatography system to obtain a xylitol phase and an L-arabinose phase;

[0038] (7) After the obtained L-arabinose phase is concentrated and crystallized, the crystallized material is separated to obtain L-arabinose crystals and L-arabinose liquid.

[0039] Example 2

[0040] A method for preparing xylitol and L-arabinose from liquid xylitol comprises the following steps:

[0041] (1) Dilute the xylose mother liquor to a concentration of 40 g / L, add 3 g / L yeast extract and inorganic salts, sterilize and set aside;

[0042] (2) inoculating Candida for fermentation, wherein the Candida can decompose sugars other than arabinose and convert xylose into xylitol, and the Candida is Candida tropicalis CJ-FID KCTC10457BP;

[0043] (3) After the fermentation is completed, the fermentation broth is centrifuged and filtered to obtain the supernatant;

[0044] (4) desalting the above clear liquid by passing it through a calcium-type ion exchange resin, and further desalting it by ultrafiltration;

[0045] (5) depigmenting the clear liquid by membrane treatment, concentrating and crystallizing the clear liquid, and separating the crystallized material to obtain xylitol crystals and xylitol mother liquor;

[0046] (6) separating the obtained xylitol mother liquor through a chromatography system to obtain a xylitol phase and an L-arabinose phase;

[0047] (7) After the obtained L-arabinose phase is concentrated and crystallized, the crystallized material is separated to obtain L-arabinose crystals and L-arabinose liquid.

[0048] Example 3

[0049] A method for preparing xylitol and L-arabinose from liquid xylitol comprises the following steps:

[0050] (1) dilute the xylose mother liquor to a concentration of 50 g / L, add 3 g / L (NH4)2SO4 and inorganic salts, sterilize and set aside;

[0051] (2) inoculating Candida for fermentation, wherein the Candida can decompose sugars other than arabinose and convert xylose into xylitol, and the Candida is Candida tropicalis KCCM 50091;

[0052] (3) After the fermentation is completed, the fermentation broth is centrifuged and filtered to obtain the supernatant;

[0053] (4) desalting the above clear solution through a calcium-type ion exchange resin;

[0054] (5) depigmenting the clear liquid by membrane treatment, concentrating and crystallizing the clear liquid, and separating the crystallized material to obtain xylitol crystals and xylitol mother liquor;

[0055] (6) separating the obtained xylitol mother liquor through a chromatography system to obtain a xylitol phase and an L-arabinose phase;

[0056] (7) After the obtained L-arabinose phase is concentrated and crystallized, the crystallized material is separated to obtain L-arabinose crystals and L-arabinose liquid.

[0057] Example 4

[0058] A method for preparing xylitol and L-arabinose from liquid xylitol comprises the following steps:

[0059] (1) Dilute the xylose mother liquor to a concentration of 180 g / L, add 5 g / L (NH4)2SO4 and inorganic salts, sterilize and set aside;

[0060] (2) inoculating Candida for fermentation, wherein the Candida can decompose sugars other than arabinose and convert xylose into xylitol, and the Candida is Candida tropicalis CJ-FID KCTC10457BP;

[0061] (3) After the fermentation is completed, the fermentation broth is centrifuged and filtered to obtain the supernatant;

[0062] (4) desalting the above clear solution through a calcium-type ion exchange resin;

[0063] (5) depigmenting the clear liquid by membrane treatment, concentrating and crystallizing the clear liquid, and separating the crystallized material to obtain xylitol crystals and xylitol mother liquor;

[0064] (6) separating the obtained xylitol mother liquor through a chromatography system to obtain a xylitol phase and an L-arabinose phase;

[0065] (7) After the obtained L-arabinose phase is concentrated and crystallized, the crystallized material is separated to obtain L-arabinose crystals and L-arabinose liquid.

[0066] Example 5

[0067] A method for preparing xylitol and L-arabinose from liquid xylitol comprises the following steps:

[0068] (1) dilute the xylose mother liquor to a concentration of 150 g / L, add 4 g / L (NH4)2SO4 and inorganic salts, sterilize and set aside;

[0069] (2) inoculating Candida for fermentation, wherein the Candida can decompose sugars other than arabinose and convert xylose into xylitol, and the Candida is Candida tropicalis KCCM 50091;

[0070] (3) After the fermentation is completed, the fermentation broth is centrifuged and filtered to obtain the supernatant;

[0071] (4) desalting the above clear liquid by passing it through a cross-linked sulfonated styrene divinyl benzene cation exchange (PS-DVB) resin;

[0072] (5) subjecting the clear liquid to secondary depigmentation by membrane treatment, and then concentrating and crystallizing, and separating the crystallized material to obtain xylitol crystals and xylitol mother liquor;

[0073] (6) separating the obtained xylitol mother liquor through a chromatography system to obtain a xylitol phase and an L-arabinose phase;

[0074] (7) After the obtained L-arabinose phase is concentrated and crystallized, the crystallized material is separated to obtain L-arabinose crystals and L-arabinose liquid.

[0075] Example 6

[0076] A method for preparing xylitol and L-arabinose from liquid xylitol comprises the following steps:

[0077] (1) dilute the xylose mother liquor to a concentration of 80 g / L, add 3 g / L (NH4)2SO4 and inorganic salts, sterilize and set aside;

[0078] (2) inoculating Candida for fermentation, wherein the Candida can decompose sugars other than arabinose and convert xylose into xylitol, and the Candida is Candida tropicalis KCCM 50091;

[0079] (3) After the fermentation is completed, the fermentation broth is centrifuged and filtered to obtain the supernatant;

[0080] (4) desalting the above clear solution through an ion exchange resin;

[0081] (5) removing pigment from the clear liquid, concentrating and crystallizing the clear liquid, and separating the crystallized material to obtain xylitol crystals and xylitol mother liquor;

[0082] (6) separating the obtained xylitol mother liquor through a chromatography system to obtain a xylitol phase and an L-arabinose phase;

[0083] (7) After the obtained L-arabinose phase is concentrated and crystallized, the crystallized material is separated to obtain L-arabinose crystals and L-arabinose liquid.

[0084] Example 7

[0085] A method for preparing xylitol and L-arabinose from liquid xylitol comprises the following steps:

[0086] (1) diluting the xylose mother liquor to a concentration of 100 g / L, adding (NH4)2SO4 4 g / L and inorganic salts, sterilizing and setting aside;

[0087] (2) inoculating Candida for fermentation, wherein the Candida can decompose sugars other than arabinose and convert xylose into xylitol, and the Candida is Candida tropicalis KCCM 50091;

[0088] (3) After the fermentation is completed, the fermentation broth is centrifuged and filtered to obtain the supernatant;

[0089] (4) desalting the above clear liquid by passing it through a cross-linked sulfonated styrene divinyl benzene cation exchange (PS-DVB) resin;

[0090] (5) subjecting the clear liquid to secondary depigmentation by membrane treatment, and then concentrating and crystallizing, and separating the crystallized material to obtain xylitol crystals and xylitol mother liquor;

[0091] (6) separating the obtained xylitol mother liquor through a chromatography system to obtain a xylitol phase and an L-arabinose phase;

[0092] (7) After concentrating and crystallizing the obtained L-arabinose phase, separating the crystallized material to obtain L-arabinose crystals and L-arabinose liquid;

[0093] (8) The obtained L-arabinose liquid is further concentrated and recrystallized to obtain L-arabinose crystals, which are mixed with the L-arabinose crystals obtained above.

[0094] Comparative Example 1

[0095] Compared with Example 1, the difference is that the xylose mother liquor is diluted to a concentration of 20 g / L, and no nitrogen source and inorganic salt are added.

[0096] Comparative Example 2

[0097] Compared with Example 2, the difference is that the xylose mother liquor is diluted to a concentration of 350 g / L, and no nitrogen source and inorganic salt are added.

[0098] Comparative Example 3

[0099] Compared with Example 3, the difference is that the fermentation supernatant obtained in step (3) is directly recrystallized to separate the xylitol phase and the L-arabinose phase.

[0100] The yields of xylitol and L-arabinose were calculated and the results are shown in Table 1.

[0101] Table 1 Yields of xylitol and L-arabinose (%)

[0102] sample Xylitol yield (%) L-arabinose yield (%) Example 1 73.5 18.3 Example 2 71.2 17.6 Example 3 76.4 18.9 Example 4 78.1 19.2 Example 5 77.6 18.5 Example 6 76.7 19.6 Example 7 80.1 18.6 Comparative Example 1 36.8 7.5 Comparative Example 2 46.3 10.4 Comparative Example 3 52.7 12.2

[0103] The xylitol and L-arabinose prepared in the examples of the present invention are significantly higher than those in the comparative examples. The purpose of the present invention is to obtain L-arabinose from xylitol. By adopting the process of the present invention, the conversion rate of xylitol can be controlled within a suitable range, so that a higher yield of L-arabinose can be separated therefrom.

[0104] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A method for preparing xylitol and L-arabinose from liquid xylitol, wherein the yield of xylitol prepared by the method is 80.1%, characterized in that: The steps include: (1) diluting the xylose mother liquor to a concentration of 100 g / L, adding (NH4)2SO4 4 g / L and inorganic salts, sterilizing and setting aside; (2) inoculating Candida for fermentation, wherein the Candida can decompose sugars other than arabinose and convert xylose into xylitol, and the Candida is Candida tropicalis KCCM 50091; (3) After the fermentation is completed, the fermentation broth is centrifuged and filtered to obtain the supernatant; (4) desalting the above clear solution through a cross-linked sulfonated styrene divinyl benzene cation exchange resin PS-DVB; (5) subjecting the clear liquid to secondary depigmentation by membrane treatment, and then concentrating and crystallizing, and separating the crystallized material to obtain xylitol crystals and xylitol mother liquor; (6) separating the obtained xylitol mother liquor through a chromatography system to obtain a xylitol phase and an L-arabinose phase; (7) After concentrating and crystallizing the obtained L-arabinose phase, separating the crystallized material to obtain L-arabinose crystals and L-arabinose liquid; (8) The obtained L-arabinose liquid is further concentrated and recrystallized to obtain L-arabinose crystals, which are mixed with the L-arabinose crystals obtained above.