WO2018116270A1 - Process for producing glucose and fructose from sucrose and separation of the glucose and fructose thereof - Google Patents

Abstract

The present invention relates to a process for the hydrolysis of a disaccharide or an oligosaccharide or a combination thereof to produce corresponding monosaccharide(s); wherein the process comprises treating the disaccharide or oligosaccharide or combination thereof with polystyrene-divinylbenzene sulphonic acid (PSDVBSA). The present invention particularly relates to a process for producing glucose and fructose from sucrose and separating glucose and fructose thereof.

Description

"PROCESS FOR PRODUCING GLUCOSE AND FRUCTOSE FROM SUCROSE AND SEPARATION OF THE GLUCOSE AND FRUCTOSE THEREOF"

This application claims the benefit of Indian provisional application number, 201641044078, filed on December 23, 2016 which is hereby incorporated by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to a process for the hydrolysis of a disaccharide or an oligosaccharide or a combination thereof to produce corresponding monosaccharide(s); wherein the process comprises treating the disaccharide or oligosaccharide or combination thereof with polystyrene-divinylbenzene sulphonic acid

(PSDVBSA). The present invention particularly relates to a process for producing glucose and fructose from sucrose and separating glucose and fructose thereof.

BACKGROUND OF THE INVENTION

Sucrose, commonly known as table sugar, is a disaccharide composed of an a-D- glucose molecule and a β-D-fructose molecule linked by an a-1, 2-glycosidic bond.

The glucose and fructose units are joined by an ether bridge in a-1 on the glucose and β-2 on the fructose orientation.

When sucrose is hydro lyzed, it forms a 1 : 1 mixture of glucose and fructose. It is called invert sugar because the angle of the specific rotation of the plain polarized light changes from a positive to a negative value due to the presence of the optical isomers of the mixture of glucose and fructose sugars.

At many times, individual glucose and fructose are required. However, the present processes available for obtaining glucose and fructose require enzyme invertase, sucrase or homogeneous acid catalyst. These available processes for separation of glucose and fructose are expensive.

The enzymatic process is highly selective, but it has several drawbacks that increases processing cost, it also includes slow enzymatic reaction, use of buffering solutions to maintain pH, narrow operating temperatures, strict feed purification requirements and periodic replacement of the enzyme due to irreversible deactivation. The most commonly used chemical catalysts for hydrolysis of sucrose to glucose and fructose belongs to two principal groups, homogeneous acid-base catalysts and heterogeneous acid-base catalysts. However, homogeneous acid-base reaction involves the extensive removal of acids and bases for recovering glucose and fructose.

EP3004126 Al teaches the manufacture of a fructoside-containing product from a glucose-rich feedstock, comprising isomerizing glucose to fructose by contacting the glucose-rich feedstock in an alcoholic medium with a basic isomerization catalyst (acidic zeolites and acidic ion exchange resins) at a temperature of at least 75 °C and pressure 2 to 25 bar, to yield a fructose-containing product; and reacting fructose-containing product obtained, with an alcohol in the presence of an acid catalyst to yield a fructoside- containing product.

US2813810A disclosed the separation of D-glucose and D-fructose from invert sugar or sucrose with equal parts of D-glucose and D-fructose by shaking with ketone containing a small amount of water, in the presence of a cation exchange resin.

US 4263052 A disclosed a process for obtaining fructose solutions or solid fructose. A raw material containing sucrose and/or similar fructofuranosides was hydrolyzed to fructose and glucose and treated with a calcium base (e.g. calcium oxide or hydroxide) to precipitate calcium-sugar complexes. The precipitate was slurred in water and then treated with phosphoric acid to liberate (e.g. at a pH of 5.5 to 9) a fructose solution of high purity (i.e. de-complex the calcium-fructose complex), with precipitation of useful calcium phosphate salts.

Thus, there is a need to develop an alternate process for hydrolyzing sucrose to glucose and fructose in equimolar concentration and then separating glucose and fructose thereof.

SUMMARY OF THE INVENTION

Accordingly, the present invention provides a process for producing glucose and fructose from sucrose comprising hydrolyzing the sucrose with polystyrene based solid acid catalyst (SAC).

In another aspect, the present invention provides a process for the hydrolysis of a disaccharide or an oligosaccharide or a combination thereof to produce corresponding monosaccharide(s); wherein the process comprises treating the disaccharide or oligosaccharide or combination thereof with polystyrene-divinylbenzene sulphonic acid (PSDVBSA) in an aqueous medium.

In yet another aspect, the present disclosure provides a process for separating glucose and fructose produced from sucrose. The process comprises: neutralizing the reaction mixture with anion exchange resin; treating the neutralized solution with charcoal; concentrating the charcoal treated solution to about 80-95 wt % to get syrup; dissolving the syrup in ethanol; adding solid glucose to the ethanolic solution until the solution become supersaturated; filtering the solid glucose obtained, and to get fructose- rich filtrate, thereafter supersaturating fructose-rich filtrate by adding pure fructose; and isolating pure fructose from the fructose-rich filtrate by crystallization.

Before the methods of the present disclosure are described in greater detail, it is to be understood that the methods are not limited to particular embodiments described, as such may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting, since the scope of the methods will be limited only by the appended claims.

Where a range of values is provided, it is understood that each intervening value, to the tenth of the unit of the lower limit unless the context clearly dictates otherwise, between the upper and lower limit of that range and any other stated or intervening value in that stated range, is encompassed within the methods. The upper and lower limits of these smaller ranges may independently be included in the smaller ranges and are also encompassed within the methods, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the methods.

Certain ranges are presented herein with numerical values being preceded by the term "about." The term "about" is used herein to provide literal support for the exact number that it precedes, as well as a number that is near to or approximately the number that the term precedes. In determining whether a number is near to or approximately a specifically recited number, the near or approximating unrecited number may be a number which, in the context in which it is presented, provides the substantial equivalent of the specifically recited number. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the methods belong. Although any methods similar or equivalent to those described herein can also be used in the practice or testing of the methods, representative illustrative methods and materials are now described.

All publications and patents cited in this specification are herein incorporated by reference as if each individual publication or patent were specifically and individually indicated to be incorporated by reference and are incorporated herein by reference to disclose and describe the methods and/or materials in connection with which the publications are cited. The citation of any publication is for its disclosure prior to the filing date and should not be construed as an admission that the present methods are not entitled to antedate such publication by virtue of prior invention. Further, the dates of publication provided may be different from the actual publication dates which may need to be independently confirmed.

It is noted that, as used herein and in the appended claims, the singular forms "a",

"an", and "the" include plural referents unless the context clearly dictates otherwise. It is further noted that the claims may be drafted to exclude any optional element. As such, this statement is intended to serve as antecedent basis for use of such exclusive terminology as "solely," "only" and the like in connection with the recitation of claim elements, or use of a "negative" limitation.

It is appreciated that certain features of the methods, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the methods, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination. All combinations of the embodiments are specifically embraced by the present invention and are disclosed herein just as if each and every combination was individually and explicitly disclosed, to the extent that such combinations embrace operable processes and/or devices/systems/kits. In addition, all sub-combinations listed in the embodiments describing such variables are also specifically embraced by the present methods and are disclosed herein just as if each and every such sub-combination was individually and explicitly disclosed herein. As will be apparent to those of skill in the art upon reading this disclosure, each of the individual embodiments described and illustrated herein has discrete components and features which may be readily separated from or combined with the features of any of the other several embodiments without departing from the scope or spirit of the present methods. Any recited method can be carried out in the order of events recited or in any other order which is logically possible.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows chromatogram of sucrose hydrolysis to glucose and fructose by polystyrene-divinylbenzene sulphonic acid (PSDVBSA);

FIG. 2 shows reusability of PSDVBSA for sucrose hydrolysis in batch process;

FIG. 3 shows chromatogram of sucrose hydrolysis by PSDVBSA for up-scaling batch process;

FIG. 4 shows chromatogram of sucrose hydrolysis by PSDVBSA in continuous stirrer tank reactor (CSTR) process;

FIG. 5 shows chromatogram of glucose separated from glucose and fructose mixture obtained from sucrose hydrolysis reaction; and

FIG. 6 shows chromatogram of fructose separated from fructose-enrich mother liquor after glucose separation.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides a process for the hydrolysis of a disaccharide or an oligosaccharide or a combination thereof to produce corresponding monosaccharide(s); wherein the process comprises treating the disaccharide or oligosaccharide or combination thereof with polystyrene-divinylbenzene sulphonic acid (PSDVBSA) in an aqueous medium.

Examples of disaccharide include, but are not limited to, sucrose, lactose, and cellobiose. In certain embodiments, the disaccharide is selected from a group comprising sucrose, lactose, cellobiose and combination thereof.

Examples of disaccharide include, but are not limited to, inulin, gluco- oligo saccharide, fructo-oligosaccharide, xylo-oligosaccharide and galacto- oligosaccharide. In certain embodiments, the oligosaccharide is selected from a group comprising inulin, gluco-oligosaccharide, fructo-oligosaccharide, xylo-oligosaccharide, galacto-oligosaccharide and a combination thereof.

Examples of monosaccharide include, but are not limited to, glucose, fructose, galactose and xylose. In certain embodiments, the monosaccharide is selected from a group comprising glucose, fructose, galactose, xylose and a combination thereof.

The present invention provides a process for producing glucose and fructose from sucrose comprising hydrolyzing the sucrose with polystyrene based solid acid catalyst (SAC). In certain embodiments, the polystyrene based acid catalyst is polystyrene- divinylbenzene sulphonic acid (PSDVBSA).

The rate of reaction and yield depends on several parameters like reaction temperature, amount of catalyst used, sugar (sucrose) concentration, pH of the reaction mixture and speed of agitation.

The reaction medium can be an aqueous medium or an organic solvent medium or a mixture thereof. The organic solvent can be an alcohol or mixture of alcohols. Examples of alcohol include, but are not limited to, methanol, ethanol, propanol, isopropanol, butanol and a mixture thereof.

The concentration of sucrose in the reaction mixture may be from about 20 wt % to about 60 wt % based on the total volume of reaction mixture. In certain embodiments, the concentration of sucrose is about 30 wt % to about 40 wt % or about from about 45 wt % to about 55 wt %. In a further embodiment, the concentration of sucrose is about 37 wt %.

The catalyst, PSDVBSA, used in the reaction may present in an amount of from about 2.5 wt % to about 20 wt % based on the total volume of reaction mixture. In certain embodiments, it is from about 5 wt % to about 15 wt % or about 10 wt%.

In certain embodiments, the reaction time is from about 1-6 h. In certain embodiments, it is about 1-5 h or about 1-4 h or about 1-3 h or about 1-2 h or about 1.5 h or about 1 h.

In certain embodiments, the reaction temperature is about 50-70 °C. In a further embodiment, the temperature is about 50 °C or about 55 °C or about 60 °C or about 65 °C about 70 °C. In certain embodiments, the temperature is about 70 °C. If the reaction temperature is above 70 °C, it may result in high rate of sulfate leaching from the catalyst, PSDVBSA. Also, for heterogeneous catalytic driven reactions high viscous solutions may limit reaction to go forward due to mass transfer (diffusional) limitations.

In the present process, pH of the reaction medium can be about 0.5-5. In certain embodiments, it is about 1-3. In a further embodiment, the pH is 1 or 1.5 or 2 or 2.5 or 3.

In certain embodiments, the present invention provides a process for producing glucose and fructose from sucrose comprising hydrolyzing the sucrose with PSDVBSA in an aqueous medium; wherein

• concentration of sucrose is from about 20 wt % to about 60 wt % based on the total volume of reaction mixture pH of the reaction medium is about 1- 3;

• PSDVBSA is present in an amount of from about 2.5 wt % to about 10 wt % based on the total volume of reaction mixture;

• reaction temperature is about 50-70 °C; and

• reaction time is about 1-6 h.

In certain embodiments, the effect of speed of agitation on the rate of reaction is determined. The speed of agitation promotes reaction by decreasing viscosity of solutions, enhances inter and intra particle mass transfer, and promotes reaction rates. The speed of agitation is varied from 50 rpm to 500 rpm. It is observed that the sucrose conversion remained same in 1 h time at different speed of agitations (50, 100, 200, 300, 400 and 500 rpm). However, speed of agitation of 200 rpm is resulted in uniform mixing.

The present disclosure also provides a process for the separation of glucose and fructose produced in the above process as described herein. The process comprises the steps of:

a) neutralizing the reaction mixture with anion exchange resin;

b) treating the neutralized solution with charcoal;

c) concentrating the charcoal treated solution to about 80-95 wt % to get sugar syrup;

d) dissolving the sugar syrup in ethanol;

e) adding solid glucose to the ethanolic solution until the solution become supersaturated; and f) filtering the solid glucose obtained in step e), and to get fructose- rich filtrate; and

g) supersaturating fructose -rich filtrate by adding pure fructose; and h) isolating pure fructose from the fructose-rich filtrate by crystallization.

The neutralization and charcoal treatment of reaction mixture can be done using any methods known in the art. In certain embodiments, the reaction mixture is passed through a column filled with anion exchange resin (exchange capacity 1.2 meq/ml), and same size other column filled with active charcoal. Both the columns are maintained at a temperature of about 40 °C by passing hot water through the jacket of the column. The feed flow rate of each column may be about 3-10 ml/min. In certain embodiments, the feed flow rate is about 5 ml/min. After the treatment, the solution obtained may be filtered to remove any unwanted or undesired particles from the solution. In certain embodiments, the solution is filtered through filtered sinter disk.

Then, the solution obtained is concentrated to get syrup. In certain embodiments, the solution is concentrated to a solid content of about 70-95 wt % and aqueous content of 0-30 wt %. In certain embodiments, the solid content is about 90 wt % and aqueous content is about 10 wt %. Any method known in the art can be employed for the concentration. In certain embodiments, the solution is concentrated under vacuum at temperature of about 40-60 °C and at a vacuum pressure of 8 mbar.

The concentrated solution (syrup) is then dissolved in ethanol in such a way that the final ethanol concentration is about 90-95 % with respect to water. Once the syrup is dissolved, a supersaturated solution is prepared by adding dry solid glucose to the solution. The solution is then incubated at temperature of about 50-70 °C for 0.5-2 h. In certain embodiments, the solution is incubated at temperature of about 60 °C for an hour. The supersaturated solution is prepared in such a way that the total concentration of glucose in the supersaturated solution is about 70-90 wt % with respect to the total sugar and water present, and concentration of total sugar in the supersaturated solution is about 95 wt %.

Thereafter, the temperature is reduced to about 10-30 °C. In certain embodiments, the temperature is reduced to about 20 °C or 25 °C or 30 °C. Then the solution is incubated for about 4-6 h with constant stirring. Thereafter, the solid (glucose) obtained is filtered and dried. Then, the mother liquor (fructose -rich filtrate) collected is supersaturated by adding solid fructose to it and incubated at about 50-70 °C for 0.5-2 h. In certain embodiments, it is incubated at about 70 °C for complete dissolution of the fructose added. The supersaturated solution is prepared in such a way that the total concentration of fructose in the supersaturated solution is about 85-95 wt % with respect to the total sugar and water present, and concentration of total sugar in the supersaturated solution is about 90-97 wt %.

The supersaturated solution is then azeotropically distilled to get sugar syrup. The sugar syrup so obtained is seeded with fructose crystals. Then ethanol was added and heated at about 50-70 °C in a crystallizer until a homogeneous solution is obtained. The homogeneous solution is then subjected to azeotropic distillation at a temperature of about 60-70 °C for about 3-6 h. Thereafter, the crystallization is initiated and collected fructose crystals. The fructose crystals can be collected by any method known in the art. In certain embodiments, the fructose crystals are isolated by centrifugation, washed with ethanol and then dried. The liquid syrup obtained after centrifugation, sent to main stream of fructose crystallizer for second stage of fructose crystallization process.

The present disclosure is further described with reference to the following examples, which are only illustrative in nature and should not be construed to limit the scope of the present disclosure in any manner.

EXAMPLES

Example 1:

Different experiments were carried out for sucrose hydrolysis at different process parameters. Each experiment was conducted twice and the results (average value) were shown in Table 1 below. It was observed the maximum sucrose conversion was attained at a temperature of 70 °C. It was also clear that with the increase in the reaction temperature from 50 to 70 °C, conversion of sucrose to glucose and fructose was increased. Sucrose conversion below 50 °C was very low. If the reaction temperature was above 70 °C, it may result in high rate of sulfate leaching from the cation exchange resin. It was also observed that the rate of reaction was very high (0.032 min^"1 for 1 h reaction time) at 70 °C. The catalyst (PSDVBSA) loading on the sucrose conversion showed that increase in catalyst loading between 2.5 to 7.5 wt.% did not show greater impact on sucrose hydrolysis reaction rate.

It was also observed that an increase in sugar concentration did not show greater impact on sucrose conversions. This may be due to the fact that higher concentration of sugar in the solution may adsorb on to the catalyst surface resulting in lower conversions.

Table 1

Example 2: Experimental validation at optimum process conditions

37.5 g of sucrose was taken and made up to volume 100 ml using water as solvent. The prepared solution was incubated at 70 °C under uniform stirring until sugar solution is completely dissolved. Cation exchange resin (polystyrene-divenylbenzene sulhonic acid, particle size 0.3-1.2 mm, 10 gm, exchange capacity 1.8meq/ml,) was added to the reaction mixture. Initial concentration of the sugar solution was taken, and samples were collected at different time intervals to measure the rate of sucrose conversion. The pH of the solution was maintained below 1.5 for faster reaction rates. The speed of agitation was kept at 200 rpm to maintain uniform mixing. Complete conversion of sucrose to glucose and fructose was observed in 1 h 15 min. Glucose and fructose were found to obtain in 1: 1 ratio. The hydro lyzed product was analyzed by HPLC and glucose fructose chromatogram are shown in FIG. 1.

Example 3: Catalyst reusability study for sucrose hydrolysis reaction The catalyst reusability studies were performed at the following conditions. Sugar solution of 50 wt. % in 100 ml solution was taken and heated to 70 °C under uniform stirring. About 10 g of PSDVBSA was loaded for sucrose hydrolysis reaction. The reaction was continued, under the same reaction conditions as depicted in example 1 , for 2 hours. The resin used was washed and reused for new set of sucrose hydrolysis reaction under the same reaction conditions as described above. Then, rate of reaction was calculated for each set of reaction using same catalyst. In the same manner, the resin was reused up to eleven cycles and no significant activity loss was observed. PSDVBSA was used up to 11 cycles with no significant loss of activity and rate of reaction. The sucrose hydrolysis reaction rate of reused resin dropped down after 12 cycles which is shown in the FIG. 2.

Example 4: Scale-up of sucrose hydrolysis reaction at the optimum process conditions

To validate the batch process that it is scalable at the optimum process conditions, sucrose hydrolysis reaction was investigated by scaling up to ten times. For this study,

1000 ml of 50 wt. % sugar solution was taken and heated to 70 °C until the sugar was completely dissolved. Then, 100 g of PSDVBSA was added to the solution. pH of the solution was maintained at 1.5, and speed of agitation was maintained at 200 rpm.

Sucrose conversion was monitored with time. Complete conversion of sucrose to glucose and fructose was observed in 1 h 30 min. (shown in FIG. 3).

Example 5: Production of glucose and fructose in a continuous stirred tank reactor

(CSTR)

The batch process of sucrose hydrolysis reaction was tested for continuous process in a CSTR reactor under the same reaction conditions as depicted in example 4. The scale-up reaction was done using 2 x 1.4 liter jacketed CSTR tank, connected serially such a way that first tank outlet is feed as second tank inlet. Inside temperature of CSTR was maintained with hot water stream supplied to jacket of the reactors. Overhead stirrer was connected for uniform mixing of the solution. In both the reactors, 375 gm sucrose was dissolved in water to a final reaction volume of 1 liter of each reactor with uniform stirring by overhead stirrer at the speed of 200 rpm. The temperature of both the reactors were adjusted and maintained to 70 °C by passing hot water stream through the reactor jacket. Once the temperature attained 70 °C, 100 gm of PSDVBSA was added and incubated for 90 minutes by contentious stirring. At the same time 37.5 wt. % feed solution was prepared by dissolving 4.9 kg of sucrose in 13 liter water. Continuous feed of sucrose solution initiated after 90 minutes adjusting inlet and outlet flow rate of 1.3 min/rnl and feed process was continued for a week. Outlet sample was analyzed in regular interval and conversion of sucrose was checked by HPLC and the final conversion obtained in collector vessels was shown in FIG. 4.

Example 6: Separation glucose from invert sugar obtained in batch/continuous process

The said glucose-fructose solution obtained in batch or continuous process (example 5 & example 6) was passed through a column (100 x 5 cm) filled with anion exchange resin (exchange capacity 1.2 meq/ml) followed by same size other column filled with active charcoal. Both the column temperatures were maintained at 40 °C by passing hot water through the jacket of the column. The feed flow rate of each column was maintained at a rate of 5 ml/min. In this process, 15 liters of glucose fructose solution (36.6 % brix) was neutralized and treated with charcoal to remove undesired color. The solution obtained was filtered through 0.45 μηι filtered sinter disk to remove particle contamination from glucose-fructose solution. The filtrate containing aqueous glucose and fructose mixture was concentrated to a solid content of 90 wt. % and aqueous content of 10 wt % under vacuum. The vacuum evaporation parameters were as follows: Temperature 60 °C; and vacuum pressure 8 mbar.

The glucose fructose syrup obtained after concentration was used for separation of glucose from the mixture. In this process, 222.g of glucose fructose syrup (200 gm solid content and 22.2 gm water content) was taken in a 1.5 L jacketed stir tank reactor and jacket temperature maintained to 60 °C by passing hot water. Then, 422 ml of anhydrous ethanol was added to the reactor with constant stirring by overhead stirrer at a speed of 200 rpm, until it dissolves completely. The final ethanol concentration was 95 % with respect to water. Once the invert sugar was dissolved, supersaturated solution was prepared by adding 200 gm pure dry solid glucose to the solution and incubated at 60° C for an hour with constant stirring. The supersaturated glucose was prepared in such a way that the total sugar molality was reached to 95 wt. % and glucose molality was reached to 71 wt. % with respect to the total sugar and water. After an hour, the temperature was reduced to 25 °C and incubated for 6 hours with constant stirring. Finally, the solid was filtered with 11 μηι cut off filter paper and dried at 60 °C in an oven. The yield obtained was 92 % with respect to total glucose (shown in Table 2) and purity of the glucose obtained was 99.8 % (shown in FIG. 5).

Table 2

Example 7: Separation of fructose from fructose enriched ethanol solution by crystallization

The process for separation of fructose was performed from the mother liquor, obtained by separation of glucose from invert sugar as described in Example 6. The compositions of mother liquor are: fructose: 99.45 gm, glucose: 24.35 gm, water: 22.2 gm and ethanol: 332.9 gm (or volume 422 ml). A supersaturated solution was prepared by adding 409.5 gm of solid fructose to the mother liquor and incubated at 70 °C for an hour for complete dissolution of the added fructose. The final compositions of supersaturated mother liquors were: Fructose: 508.95 gm, Glucose: 24.35 gm, water: 22.2 gm and ethanol: 422 ml. The supersaturated solution was prepared in such a way that total molality of sugar solution was reached to 96 wt. % and fructose molality was reached to 91.6 wt % with respect to total sugar and water. The final ethanol concentration in the solution was 95 % with respect to water. Then the solution was concentrated by vacuum evaporation to reduce water content by ethanol distillation. The azeotropic ethanol distillate was dehydrated with molecular sieves and reused for fructose crystallization process. The sugar syrup obtained after ethanol distillation was seeded with 100 mg of anhydrous fructose crystal. Then, anhydrous ethanol (1045 ml) was added and resolved the sugar syrup at 65 °C in a crystallizer equipped with vacuum distillation set up. Once the solution became homogeneous, 500 mbar vacuum was applied to remove azeotropic ethanol slowly from the mixture by incubating at 65 °C for 5 hours. The crystallization process was initiated after an hour and crystallization process was terminated at the final weight of 755 gm after 5 hours. The fructose crystals were recovered by centrifugation and washed with anhydrous ethanol and dried in an oven at 60 °C. The liquid syrup obtained after the centrifugation, was sent to main stream of fructose crystallizer for second stage of fructose crystallization process. The purity of fructose obtained was almost 100% (shown in FIG. 6) and the yield was 70 % with respect to the total fructose (Table 3).

Table 3

Advantages of The Present Process:

• The process is eco-friendly, fast, simple and scalable • The reagent used for separation is non-toxic and easily recoverable

• The process developed with SAC has high selectivity towards conversion

• Same catalyst can be used for isomer separation and chemical conversion

• The process is less prone to contamination

Although the foregoing invention has been described in some detail by way of illustration and example for purposes of clarity of understanding, it is readily apparent to those of ordinary skill in the art in light of the teachings of this invention that certain changes and modifications may be made thereto without departing from the spirit or scope of the appended claims.

Accordingly, the preceding merely illustrates the principles of the invention. It will be appreciated that those skilled in the art will be able to devise various arrangements which, although not explicitly described or shown herein, embody the principles of the invention and are included within its spirit and scope. Furthermore, all examples and conditional language recited herein are principally intended to aid the reader in understanding the principles of the invention and the concepts contributed by the inventors to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions. Moreover, all statements herein reciting principles, aspects, and embodiments of the invention as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, it is intended that such equivalents include both currently known equivalents and equivalents developed in the future, i.e., any elements developed that perform the same function, regardless of structure. The scope of the present invention, therefore, is not intended to be limited to the exemplary embodiments shown and described herein. Rather, the scope and spirit of present invention is embodied by the appended claims.

Claims

The Claim:

1. A process for the hydrolysis of a disaccharide or an oligosaccharide or a combination thereof to produce corresponding monosaccharide(s); wherein the process comprises treating the disaccharide or oligosaccharide or combination thereof with polystyrene-divinylbenzene sulphonic acid (PSDVBSA) in an aqueous medium.

2. The process as claimed in claim 1, wherein the disaccharide is selected from a group comprising sucrose, lactose, cellobiose and combination thereof.

3. The process as claimed in claim 1, wherein the oligosaccharide is selected from a group comprising inulin, gluco-oligosaccharide, fructo-oligosaccharide, xylo- oligo saccharide, galacto-oligosaccharide and a combination thereof.

4. The process as claimed in claim 1, wherein monosaccharide is selected from a group comprising glucose, fructose, galactose, xylose and a combination thereof.

5. The process as claimed in claim 1, wherein concentration of sucrose is from about 20 wt % to about 60 wt % based on the total volume of reaction mixture.

6. The process as claimed in claim 1, wherein PSDVBSA is present in an amount of from about 2.5 wt % to about 20 wt % based on the total volume of reaction mixture.

7. The process as claimed in claim 6, wherein PSDVBSA is present in an amount of about 5-10 wt % based on the total volume of reaction mixture.

8. The process as claimed in claim 1, wherein the reaction temperature is about 20- 90 °C.

9. The process as claimed in claim 1, wherein the reaction temperature is about 50- 70 °C.

10. The process as claimed in claim 1, wherein the reaction time is about 1-6 h.

11. The process as claimed in claim 1 , wherein the reaction mixture has a pH of about 0.5-5.

12. The process as claimed in claim 11, where the reaction mixture has a pH of about 1-3.

13. A process for the separation of glucose and fructose produced in the process as claimed in claim 1 ; wherein the process comprises the steps of:

a) neutralizing the reaction mixture with anion exchange resin; b) treating the neutralized solution with charcoal;

c) concentrating the charcoal treated solution to about 80-95 wt % to get sugar syrup;

d) dissolving the sugar syrup in ethanol;

e) adding solid glucose to the ethanolic solution until the solution become supersaturated; and

f) filtering the solid glucose obtained in step e), and to get fructose- rich filtrate; and

g) supersaturating fructose -rich filtrate by adding pure fructose; and h) isolating pure fructose from the fructose -rich filtrate by crystallization.

14. The process as claimed in claim 13, wherein ethanol concentration is about 90- 95%, and supersaturated solution is prepared by incubating the mixture at about 50-70 °C for 0.5-2 h.

15. The process as claimed in claim 13, wherein concentration of glucose in the supersaturated solution is about 70-90 wt % with respect to the total sugar and water present; and concentration of total sugar in the supersaturated solution is about 95 wt %.

16. The process as claimed in claim 15, wherein temperature of the supersaturated solution is allowed to about 10-30 °C to initiate crystallization of the glucose.

17. The process as claimed in claim 13, wherein isolation of the fructose from the fructose-rich filtrate comprises the steps of:

adding solid fructose to the fructose-rich filtrate until the solution become supersaturated;

concentrating the supersaturated solution to obtain sugar syrup;

seeding the sugar syrup with solid fructose and initiating crystallization; and

isolating fructose crystals.

18. The process as claimed in claim 17, wherein ethanol concentration is about 90- 95%, and supersaturated solution is prepared by incubating the mixture at about 50-70 °C for 0.5-2 h.

19. The process as claimed in claim 17, wherein concentration of fructose in the supersaturated solution is about 85-95 wt % with respect to the total sugar and water present; and concentration of total sugar in the supersaturated solution is about 90-97 wt %.

20. The process as claimed in claim 17, wherein the seeded syrup is heated at about 50-70°C until the solution become homogeneous.

21. The process as claimed in claim 20, wherein the homogeneous solution is azeotropically distilled before the initiation of crystallization.