JPH03224500A - Production of xylose - Google Patents

Abstract

PURPOSE:To efficiently obtain the subject xylose of high purity at an industrially low cost by carrying out acid hydrolysis of the core layer of a babassupalm in a specified condition. CONSTITUTION:The core layer of a babassupalm is hydrolyzed in 0.1-3 N mineral acid at 100-130 deg.C, preferably 120 deg.C and at the ordinary pressure or an applied pressure, and the resultant liquid layer is subsequently subjected to the active carbon treatment, the ion-exchange resin treatment, etc., thus carrying out separation and purification of the objective compound. In addition, before the above-mentioned hydrolysis, impurities are preferably removed by boiling the raw material in water or a dilute acid of <=0.1N.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention uses the core layer of Babassu coconut shell as a raw material and applies specific hydrolysis conditions to produce high-purity xylose industrially at low cost and efficiently. Concerning how to manufacture well.

[Prior Art] Conventionally, xylose has been produced from natural plant materials containing large amounts of cellulose and various hemicelluloses in addition to xylan (for example, monocotyledonous plants such as oat, corn, or cottonseed, and beech, poplar, and birch). Hydrolysis using mineral acids, organic acids, or enzymatic agents as starting materials from dicotyledonous plants such as deciduous trees (e.g., deciduous trees, etc.) and waste organic raw materials from the valve and paper industry (wastes such as sulfite valves, kraft valves, semi-chemical valves, etc.) Attempts have been made to obtain this method. Furthermore, since these hydrolysates contain many types of saccharides and other impurities, methods such as fermentation removal of impurities using yeast have been used to purify them.

[Problems to be Solved by the Invention] Generally, these starting materials are composed of various polysaccharides, so in addition to the target xylose, the obtained hydrolyzed sugar solution also contains pentose sugars such as arabinose and glucose,
Hexoses such as mannose and galactose and acetic acid are produced.

Therefore, it is extremely difficult to separate each component from this mixture and recover xylose with high purity, which requires a lot of cost and time.

On the other hand, as a method for producing xylose without contamination with other impurities as mentioned above, there is a method using the outer skin layer or core layer of the Babassu coconut shell as a raw material and using an enzyme agent (Japanese Patent Publication No. 56-50960). However, this method requires pretreatment steps such as de)nognonin and alkaline extraction of xylan, as well as post-treatment to separate the enzymatic hydrolyzate into xylose, a neutral component, and polyanionic substances, which are acidic components, including uronic acid. However, there were problems in that the process to obtain only xylose was complicated, and it was expensive and time consuming.

In addition, using natural products as raw materials for boat fishing poses problems regarding the stability of raw material supply. For example, if cottonseed husks are used as raw materials (Japanese Patent Publication No. 43-122371), due to the decrease in the utility value of cottonseed oil, there will be problems in the future. However, there is a problem with the stable supply of raw materials.In addition, in the plants used as raw materials, the state of existence of xylan is as follows.
They differ depending on their origin, and their behavior towards heat and chemicals also differs depending on the molecular weight of the xylan itself and the state of bonding with lignin and cellulose.

As a raw material for the production of xylose, the core layer of the Babasu coconut shell is rich in bexilan content compared to other raw materials, as stated in Japanese Patent Publication No. 56-50960, and the raw wood grows naturally in large quantities in South America such as Brazil, so it is used as a raw material. Excellent supply stability. However, from the viewpoint of producing only xylose, the above-mentioned patented production method requires a complicated process and is not necessarily advantageous in terms of cost.

Therefore, the present invention aims to produce high-purity xylose industrially at low cost and simply by using the core layer of Babassu coconut shell as a raw material.

In addition, the Babassupalm referred to in this invention refers to Babassupalm, Orbignya palm, which is classified as a plant of the palm family.
There are names such as rtianaBarb-Rodr, and the nuclear layer refers to the part called Enclcarpo that envelops the seed.

[Means for Solving the Problems] In the present invention, the core layer of Babassu coconut shell, which has excellent raw material supplyability, is used, and the hydrolysis conditions are 0.1 to 3.
．． using 0N mineral acid at 100130°C, preferably 1
Boil at around 20°C under normal pressure or pressure. This makes it possible to suppress the production of glucose, arabinose and oligosaccharides and to produce highly pure xylose.

Furthermore, in order to use Babasu coconut shell as a raw material for the core layer, if the above hydrolysis is performed after a pretreatment step of adding water or a dilute acid of 0.1N or less and boiling it to wash away impurities dissolved in the liquid,
It was also discovered that highly purified xylose could be obtained.

Separation and purification of xylose from the obtained hydrolyzate is achieved by treatment with activated carbon, treatment with an ion exchange resin, crystallization, etc.

This will be described in detail below using examples and the like.

[Experimental Example 1 Production of xylose-containing liquid by co-sulfuric acid treatment (1) The core layer of the Babassu coconut shell was taken out and reduced to a particle size of 0.5 using a Willey mill.
A powder was obtained by pulverizing the powder to about 2.0 mm.

A sample of 8 and 00 g (10 series) of this powder (dry product) was added to 100 ml of 0-50% (v/v) (approximately O-18 N) sulfuric acid in an Erlenmeyer flask with a stopper, and the mixture was heated at 120°C for 1 hour.
An attempt was made to elute xylose in an autoclave at atmospheric pressure for 60 minutes. The acid concentration of each series is shown in Table 1.

After the heat treatment, the hydrolyzate was filtered using glass fiber filter paper to separate solid matter and filtrate. The solid matter was washed with water until the washing solution became neutral, dried at 105° C. for 5 hours, and weighed. The filtrate was neutralized with barium hydroxide to pH 6,56,9, the resulting barium sulfate was removed by filtration, the filtrate was concentrated, freeze-dried, and weighed. Table 2 shows the mass balance of eluates and solids for each sulfuric acid concentration of the Babassu coconut shell core layer powder.

The yield of eluate relative to the raw material was determined using experimental system D-F (sulfuric acid concentration 1
．． The best efficiency of 40% or more was obtained at 0 to 5.0% (V/V).

In order to investigate the sugar composition of the eluate, it was developed on a silica gel TLC plate (MERCK Art, 5554), and surprisingly, experimental system C-E (sulfuric acid concentration 0.5-2.
It was found that only xylose was produced in the sample treated with 0% (V/V) sulfuric acid concentration (Figure 1). In addition, in experimental system 0-B (sulfuric acid concentration O ~ 0.2% (V/V)), a large amount of arabinose impurities derived from other hemicelluloses contained in the Babassu coconut shell core layer were contained, and in experimental system F~
(It has been shown that at sulfuric acid concentrations of 5.0 to 50.0% (V/V), glucose derived from cellulose is produced, and that highly pure xylose can only be obtained at sulfuric acid concentrations between this range. Ta.

Next, the total sugar content of each eluate was determined by the orcinol sulfuric acid method, and the reducing sugar content was determined by the Nelson-Somogi method, and the results are shown in Table 3. The ratio of total sugar amount is experimental system A-F (sulfuric acid concentration 0.1-5.
0% (v/v)), a value of around 60% was obtained, and the amount of reducing sugar was determined by the experimental system C-F (sulfuric acid concentration 0.5-5.0% (v/v)).
), a value of around 55% was obtained. In addition, when converting the degree of polymerization of sugars contained in the eluate using the value of total sugar amount/reducing sugar amount, it is approximately 1 in experimental system C-G (sulfuric acid concentration 1.0 to 10.0% (v/v)). , it can be seen that almost all of the eluted sugars have been broken down to monosaccharides. Furthermore, it was revealed that in the experimental system H1 (sulfuric acid concentration 20.0 to 50.0% (v/v)), the excessive decomposition reaction of sugar was progressing.

The yield of sugar in the eluate relative to the raw material was 23% or more in experimental systems D to F (sulfuric acid concentration 1.0 to 5.0% (V/V)) (Table 4).

Above, the yield of sugar content in the eluate relative to the raw material, the purity of xylose,
As a result of considering all the experimental results regarding sugar content and hydrolysis system, the experimental system was as follows: E (sulfuric acid concentration 1.0.2.0% (V/
It was revealed that the eluate obtained by the treatment in (V)) did not contain any contaminant sugars and that xylose could be obtained in high yield.

Table 1 Table 1 (Weight is calculated as dry weight) Table ＼ Table [Experiment Example 2] Xylose syrup in mM Experimental system of Experiment Example 1 The lyophilized product of a portion is also simply expressed as the eluate.) 1. OOg
Dissolve in 10ml of water, add 50ml of coconut shell activated carbon (Wako Pure Chemical Industries)
mg was added and treated at 4'O'C for 60 minutes. Activated carbon was removed by filtration, and the volume of the treated solution was adjusted to 10 ml. This 5
．． 00ml of strongly acidic ion exchange resin GC120()l”
) Type 1-1.5ml and strongly basic ion exchange resin lR4
Purification was performed by passing through a 10C0)l-) type 1-1.5mlO column.

As a result of testing the sugar purity of the syrup at each purification stage using the orcinol sulfuric acid method, the final treated product was 92.8% in the experimental system.
90.2% (Table 5), and when the sugar composition was examined by HPLC, only a xylose peak was detected in each case.

The results are shown in Figure 2. Note that the HPLC conditions are mobile phase: niacetonitrile:water = 80:20 flow rate: 0.5ml
/min Column: TO3OHAm1de 80 (4.6mm
IDx 25cm) Temperature 280°C Detector: TO5O) I R1-8012 Device: T
O5OH5C-8010 Sample injection amount: 20 μI (acetonitrile: sample aqueous solution = 80:20) Table 4 also shows the yield of sugar to raw material in each purification step. The yield of xylose based on the raw material in the final treated product was approximately 21%.

Table 5 [Experimental Example 3] Production of xylose-containing liquid including pretreatment (2
) Babassu coconut core layer powder (dried) 8. OOg (3 series 0-2, A-2, B-2) was used as a sample, and O~0.2% (v/v) (approximately 0~0.0.
In addition to 100 ml of water or dilute sulfuric acid solution of 120
Pretreatment was carried out in an autoclave under pressure of 1 atm at 0.degree. C. for 60 minutes, and the eluate was removed by filtration. 4.00 g (in terms of dry matter) of each of the solids obtained was used as a raw material for producing the following xylose-containing liquid. The sulfuric acid concentration in the pretreatment of each experimental system is based on the experimental systems shown in Table 1 with the same alphabetical symbol. In other words, water was used in the ○-2 experimental system, and 0 was used in the A-2 experimental system.
．． 1% and 0.2% dilute sulfuric acid was used in the B-2 experimental system.

4.00 g (dry weight) of the solids treated under each pretreatment condition was placed in a stoppered Erlenmeyer flask with 50 m of 1% (v/v) sulfuric acid.
1, and an attempt was made to elute xylose in an autoclave at 120° C. and a pressure of 1 atm for 60 minutes. Table 6 shows the results of determining the mass balance of eluate and solid matter.

Examination of the sugar composition of the eluate by TLC revealed that only xylose was produced (Figure 3).

In addition, as a result of measuring the total sugar amount and reducing sugar amount in the same manner as in Experimental Example 1, the ratio of total sugar amount was as shown in Table 7 for experimental system 0-2.
In A-2, it was around 80%, which was an improvement of around 20% compared to experimental systems A to F obtained in Experimental Example 1 in which no pretreatment was performed. Sulfuric acid concentration (0.2% (V/
In V)'), there was a large loss of xylose in the pretreatment step, and no improvement in purity was observed.

This result shows that pretreatment has the effect of reducing the consumption of activated carbon and ion exchange resin used in subsequent purification, and that with appropriate pretreatment conditions, the value of total sugar content/reducing sugar content is approximately 1. This shows that almost all of the produced sugars are monosaccharides.

As shown in Table 4, the sugar yield relative to the raw material was determined for experimental system ○-2.
is the highest at approximately 24%, and the pretreatment is with water or 0.1% (V/
It is clear that a method using sulfuric acid of grade V) is better.

Table 6 [Experimental Example 4] Xylose Production (3) Based on the previous experimental examples, an attempt was made to scale up xylose production. Add tap water to 300.0 g of powder (dry equivalent) to make a total volume of 1500 ml, and place in a 2 L polypropylene container at 120°C and pressurized (1 atm gauge pressure).
Processed for 60 minutes. A residue of 289.8 g (in terms of dry matter) was obtained by filtration, and 1% (V/V) sulfuric acid (approximately 0.36 N) was added to the residue to make a total volume of 1500 ml.
It was treated under pressure at 0°C for 60 minutes. Filter to remove residue;
Slaked lime was added to the filtrate to neutralize it, and the resulting calcium sulfate was removed by filtration. The filtrate was concentrated, the precipitate was removed by filtration again, and treated with activated carbon and ion exchange resin according to the method described in Experimental Example 2 to obtain syrup, and a portion of this was subjected to HPLC analysis.
The sugar composition was analyzed. The results are shown in Figure 4. The remaining syrup is concentrated and dried to a solid content of 8 with a sugar purity of 91.2%.
1.4g was obtained. Calculating the yield of sugar to raw materials is 24.
It was 7%.

[Effects of the Invention] Conventionally, when producing xylose from plant materials, there were problems with the formation of contaminant sugars and the generation of acetic acid due to high temperature treatment (130° C. or higher). The present inventors have determined that the by-product of acetic acid is 100~
They discovered that this can be avoided by setting the temperature as low as 130°C, and that high-purity xylose can be produced by simply selecting the sulfuric acid treatment conditions using Babassu coconut shell kernels as a raw material. Babasu palm grows naturally in large quantities in South America, and the core layer in particular accounts for 58% of the palm, but it is of little use and is an untapped resource with excellent supply stability as a raw material. Moreover, the simplicity of the inherent process makes it possible to produce high purity xylose at low cost, making it extremely useful industrially.

[Brief explanation of drawings]

FIG. 1 shows the sugar composition of the eluate obtained by treating the core layer of Babasu coconut shell with sulfuric acid at various concentrations, determined by TLC. Figures 2 (A), (B), and (C) show the sugar compositions determined by IPLC of the xylose standard sample, the experimental sample, and the purified product using activated carbon and ion exchange resin of E. FIG. 3 shows the sugar composition by TLC of the eluate obtained by treatment with 1% (V/V) sulfuric acid after pretreatment. FIGS. 4(A) and 4(B) show the sugar compositions of the xylose standard sample and the syrup obtained by the method of Experimental Example 4 by HPLC. Developing solvent: ethyl acetate; pyrite: Qt acid: water = 5: 5
; l: Color former: Anilino-phthalic acid color former σ, Uromenun diagram Developing solvent: Ethylpyridine acetate; Acetic acid; Water =: 5 ;! i:1; Figure 4

Claims (2)

[Claims] (1) A liquid phase is obtained by treating the core layer of Babasu coconut shell in 0.1-3.0N mineral acid at 100,130°C under normal pressure or under pressure, and the xylose contained in this liquid phase is separated and purified. A method for producing high-purity xylose, characterized by: (2) The core layer of the Babassu coconut shell is pretreated to separate impurities that dissolve in water or a dilute acid solution of 0.1N or less. Method.