阅读说明：本技术 一种海水催化降解多糖的方法和一种复合低聚糖 (Method for catalytically degrading polysaccharide by seawater and composite oligosaccharide ) 是由 蒋建新 张威伟 张献琨 朱莉伟 于 2020-04-16 设计创作，主要内容包括：本发明提供一种海水催化降解多糖的方法和一种复合低聚糖,所述方法包括：以海水为溶剂对甘蔗渣进行预处理,在145～155℃下加热反应120～150min,过滤；将皂荚胚乳片与海水在120～130℃下,进行水合反应90min；将上述过滤得到的甘蔗渣预处理液与水合后的皂荚胚乳片混合,在155～165℃下降解反应20～30min。本发明以海水作为溶剂以及催化剂,通过合适的反应条件,得到了具有更高生物功能特性的2～9个单糖聚合的复合低聚糖,包括甘露低聚糖和低聚木糖,且木四糖和甘露四糖比例明显提高。本发明整个降解过程仅使用海水,未使用新鲜淡水和任何额外催化剂,节省了淡水资源,而且比单一低聚糖生产效率高。(The invention provides a method for degrading polysaccharide by seawater catalysis and a composite oligosaccharide, wherein the method comprises the following steps: pretreating bagasse by using seawater as a solvent, heating and reacting at 145-155 ℃ for 120-150 min, and filtering; carrying out hydration reaction on the gleditsia sinensis endosperm slices and seawater at 120-130 ℃ for 90 min; mixing the bagasse pretreatment solution obtained by filtering with hydrated gleditsia sinensis endosperm slices, and performing degradation reaction at 155-165 ℃ for 20-30 min. According to the invention, seawater is used as a solvent and a catalyst, and the composite oligosaccharide with higher biological functional characteristics and polymerized by 2-9 monosaccharides is obtained through proper reaction conditions, and comprises the mannooligosaccharide and xylooligosaccharide, and the ratio of xylotetraose to mannotetraose is obviously improved. The whole degradation process of the invention only uses seawater, does not use fresh water and any additional catalyst, saves fresh water resources, and has higher production efficiency than single oligosaccharide.)

1. A method for degrading polysaccharide by seawater catalysis is characterized by comprising the following steps:

pretreating bagasse by using seawater as a solvent, heating and reacting at 145-155 ℃ for 120-150 min, and filtering;

carrying out hydration reaction on the gleditsia sinensis endosperm slices and seawater at 120-130 ℃ for 90 min;

mixing the bagasse pretreatment solution obtained by filtering with hydrated gleditsia sinensis endosperm slices, and performing degradation reaction at 155-165 ℃ for 20-30 min.

2. A method according to claim 1, wherein the bagasse accounts for 8-12% by weight of the seawater in the pretreatment process.

3. The method of claim 1, wherein the hydration reaction comprises a 1:0.6 ratio of the pieces of gleditsia sinensis endosperm to seawater.

4. The method according to claim 1, wherein the mass ratio of the bagasse to the gleditsia sinensis endosperm slices is 1: 0.7-0.8.

5. The method according to any one of claims 1 to 4, further comprising the step of adding seawater to perform an enzymolysis reaction to prepare enzymolysis lignin and glucose by using solid residues obtained by bagasse pretreatment as enzymolysis substrates.

6. The method of claim 5, wherein sasanqua saponin is further added to the enzymatic reaction.

7. The method according to claim 6, wherein the specific conditions of the enzymatic hydrolysis reaction include: the concentration of an enzymolysis substrate is 7.5 percent, the dosage of cellulase is 18 FPU/g-cellulose, the concentration of the sasanqua saponin is 0.4g/L, the enzymolysis temperature is 48 ℃, the initial pH of an enzymolysis reaction system is 4.8, and the enzymolysis time is 72 hours.

8. The method according to any one of claims 1 to 7, wherein the bagasse particle size is less than 20 mesh, and the moisture content is less than 10%;

and/or, the gleditsia sinensis endosperm pieces are separated from the gleditsia sinensis seeds by a roasting method, and the impurity content is less than 2%.

9. A complex oligosaccharide obtained by the method of any one of claims 1 to 8.

10. The complex oligosaccharide of claim 9, wherein the complex oligosaccharide comprises greater than 40% mannooligosaccharide and greater than 10% xylooligosaccharide, and wherein the mannooligosaccharide comprises mannobiose, mannotriose, mannotetraose, and mannopentaose.

Technical Field

The invention relates to the field of biomass chemistry and chemical engineering, in particular to a method for degrading polysaccharide by seawater catalysis and a composite oligosaccharide.

Background

The total amount of bioenergy grown annually on earth is over 1400 hundred million tons (dry weight), and biomass is rich in polysaccharides. For example, the seed of Gleditsia sinensis contains approximately 40% galactomannan, the main chain of galactomannan gum is a straight chain polysaccharide formed by connecting beta-D-galactopyranose residues through 1, 4-glycosidic bonds, and the side chain is formed by connecting single alpha-D-galactopyranose residues with C6 of mannopyranose in the main chain through 1, 6-glycosidic bonds. Galactomannan gum is widely used in food and medicine, textile printing and dyeing, energy mining, daily chemical and other industries due to its unique rheological property. Researches in recent years show that the galactomannan degradation product has high functional activity, and can be used for proliferation of dietary fiber and intestinal beneficial flora, improvement of systemic nutrient absorption and the like.

In addition, the total annual production of sugar cane on earth is also high, leaving a large amount of sugar cane bagasse after it is used to produce sucrose. The traditional method for processing the bagasse is used as fuel or is not used for waste, and the utilization rate is low. The bagasse contains about 37.6% of glucan and 21.9% of xylan, makes full use of natural biomass polysaccharide resources, develops products such as functional oligosaccharides and monosaccharides, and has important significance in promoting development of industries such as biomedicine, animal feed, biomass chemicals and the like.

At present, the degradation and utilization of biomass polysaccharide have the following bottlenecks: the biomass structure is compact and difficult to degrade, and the pretreatment cost is high; a large amount of fresh water is needed in the degradation process; the chemical catalyst in the degradation process is difficult to recycle, and the enzyme catalyst is expensive; the degradation product has more by-product impurities, etc.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a method for degrading polysaccharide by seawater catalysis and a composite oligosaccharide.

The invention provides a method for degrading polysaccharide by seawater catalysis, which comprises the following steps:

pretreating bagasse by using seawater as a solvent, heating and reacting at 145-155 ℃ for 120-150 min, and filtering;

carrying out hydration reaction on the gleditsia sinensis endosperm slices and seawater at 120-130 ℃ for 90 min;

mixing the bagasse pretreatment solution obtained by filtering with hydrated gleditsia sinensis endosperm slices, and performing degradation reaction at 155-165 ℃ for 20-30 min.

According to the invention, seawater is used as a solvent and a catalyst, polysaccharides in bagasse and gleditsia sinensis endosperm slices are efficiently degraded through proper pretreatment and degradation reaction conditions, and the seawater and the gleditsia sinensis endosperm slices can promote catalytic degradation reaction of metal ions in the seawater on the polysaccharides through hydration, so that the composite oligosaccharide with higher biological functional characteristics and polymerized by 2-9 monosaccharides is obtained, wherein the composite oligosaccharide comprises mannan oligosaccharide and xylooligosaccharide, and the ratio of xylotetraose to mannan is obviously improved. The whole degradation process only uses seawater, does not use fresh water and any additional catalyst, saves a large amount of fresh water resources, has high and simple process flow, and improves the efficiency compared with the single oligosaccharide production.

Further, in the pretreatment process, the bagasse accounts for 8-12% of the seawater by mass volume.

Further, in the hydration reaction, the mass ratio of the gleditsia sinensis endosperm slices to the seawater is 1: 0.6.

Further, the mass ratio of the bagasse to the gleditsia sinensis endosperm slices is 1: 0.7-0.8.

Furthermore, the method also comprises the step of taking solid residue obtained by pretreating bagasse as an enzymolysis substrate, and adding seawater for enzymolysis reaction to prepare enzymolysis lignin and glucose.

The invention degrades polysaccharide to obtain composite oligosaccharide, and simultaneously co-produces glucose and enzymatic hydrolysis lignin, thereby being beneficial to resource utilization and improving the value added of products. The seawater is used as a bagasse pretreatment solvent in the early stage, so that the degradation and dissolution of hemicellulose are promoted, and favorable conditions are provided for the enzymolysis reaction of pretreated sugarcane residues. In the technical scheme, the sugarcane residue is further subjected to enzymolysis reaction in a seawater system, so that the yield of glucose is more than 80%, and the yield of enzymolysis lignin is more than 95%.

Further, the oil-tea saponin is also added in the enzymolysis reaction.

In the technical scheme, the added oil tea saponin can improve the concentration of a biomass enzymolysis conversion substrate and reduce the dosage of enzyme.

In a preferred embodiment of the present invention, the specific conditions of the enzymatic hydrolysis reaction include: the concentration of an enzymolysis substrate (namely solid residue obtained by pretreating bagasse) is 7.5%, the dosage of cellulase is 18 FPU/g-cellulose, the concentration of sasanqua saponin is 0.4g/L, the enzymolysis temperature is 48 ℃, the initial pH of an enzymolysis reaction system is 4.8, and the enzymolysis time is 72 hours.

The bagasse grain size is less than 20 meshes, and the moisture content is less than 10%.

The gleditsia sinensis endosperm slices are separated from gleditsia sinensis seeds by a baking and frying method, and the impurity content is less than 2%.

The gleditsia sinensis is an ecological and economic tree seed, the gleditsia sinensis seed contains rich galactomannan, the bagasse is industrial solid waste, and the bagasse contains rich xylan and glucan, so that the gleditsia sinensis is an ideal raw material for preparing oligosaccharide and sugar platform products. The seawater contains abundant sodium, potassium, magnesium, calcium and chlorine elements, has a high-efficiency catalytic action on degradation of polysaccharide, and also contains microelements such as iron, copper, zinc, manganese, selenium and the like required by animals and microorganisms. The raw materials used in the invention are all green and cheap ideal raw materials.

In a preferred embodiment of the present invention, the method for the seawater-catalyzed degradation of polysaccharides comprises the following steps:

hydration reaction: stirring and hydrating the gleditsia sinensis endosperm slices and seawater at the mass ratio of 1:0.6 at 120-130 ℃ for 90min, and performing three-roller tabletting and crushing on the hydrated gleditsia sinensis endosperm slices for later use;

pretreatment reaction: adding seawater into bagasse until the mass fraction of the bagasse is 10% (w/v), heating and reacting at 150 ℃ for 120-150 min, cooling and filtering after the reaction is finished, and respectively reserving filtrate and solid residue for later use;

the mass ratio of the raw material bagasse to the gleditsia sinensis endosperm slices is 1: 0.7-0.8;

polysaccharide degradation reaction: mixing the filtrate obtained by bagasse pretreatment with hydrated gleditsia sinensis endosperm slices, heating to react at 155-165 ℃ for 20min, cooling after the reaction is finished, adding 2% resin to perform metal ion adsorption for 30min, performing vacuum concentration, and performing spray drying to obtain composite oligosaccharide;

and (3) carrying out enzymolysis reaction: taking bagasse pretreated solid residues as an enzymolysis substrate, carrying out enzymolysis in a seawater reaction system, wherein the concentration of the enzymolysis substrate is 7.5%, the dosage of cellulase is 18 FPU/g-cellulose, the concentration of sasanqua saponin is 0.4g/L, the temperature is 48 ℃, the initial pH of the enzymolysis reaction system is 4.8, the enzymolysis time is 72 hours, the enzymolysis reaction is finished, filtering is carried out, filter residues are dried to obtain enzymolysis lignin, and the filtrate is glucose solution.

Wherein, the hydration reaction and the pretreatment reaction have no fixed sequence, can be carried out simultaneously, or can be carried out one first and then the other;

the polysaccharide degradation reaction and the enzymolysis reaction also have no fixed sequence, and can be carried out simultaneously, or one of the polysaccharide degradation reaction and the enzymolysis reaction can be carried out first and then the other polysaccharide degradation reaction and the enzymolysis reaction can be carried out.

The invention also provides a composite oligosaccharide, which is prepared by any one of the methods.

Furthermore, the content of the manna oligosaccharide in the compound oligosaccharide is more than 40%, the content of the xylo-oligosaccharide is more than 10%, and the manna oligosaccharide comprises manna disaccharide, manna trisaccharide, manna tetrasaccharide and manna pentasaccharide.

According to the invention, seawater is used as a solvent and a catalyst, polysaccharides in bagasse and gleditsia sinensis endosperm slices are efficiently degraded through proper pretreatment and degradation reaction conditions, and the seawater and the gleditsia sinensis endosperm slices can promote catalytic degradation reaction of metal ions in the seawater on the polysaccharides through hydration, so that 2-9 monosaccharide polymerized composite oligosaccharides with higher biological functional characteristics are obtained, wherein the composite oligosaccharides comprise mannan oligosaccharide and xylooligosaccharide, and the ratio of xylotetraose to mannan is obviously improved. The whole degradation process only uses seawater, does not use fresh water and any additional catalyst, saves a large amount of fresh water resources, has high and simple process flow, and improves the efficiency compared with the single oligosaccharide production.

Drawings

FIG. 1 is a process flow diagram of seawater degradation of polysaccharides in an embodiment of the present invention.

Detailed Description

The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention. The examples do not show the specific techniques or conditions, according to the technical or conditions described in the literature in the field, or according to the product specifications. The reagents or instruments used are conventional products available from regular distributors, not indicated by the manufacturer.

In the following examples, bagasse is ground by a dry method, sieved by an industrial vibrating screen and sieved by a 20-mesh sieve, and the moisture content is less than 10%;

the Gleditsia sinensis endosperm sheet is separated from Gleditsia sinensis seed by parching, and the impurity is less than 2%.