CN105274164A - Preparation method of galactooligosaccharides - Google Patents

Abstract

The invention relates to a method of purifying low-content galactooligosaccharides, comprising following steps: lactose dissolution, enzymatic reaction, decoloring by enzyme deactivation, desalination by nano-filtration, ion exchange, concentration, and preparation of high-purity galactooligosaccharide syrup. The high-purity galactooligosaccharide syrup is roughly desalinated by means of filtration by nano-filtration membranes before the ion exchange so as to remove most salt ions, electric conductivity of feed liquid is substantially reduced, the consumption of acid-bases in the production of galactooligosaccharides is lowered, fewer waste acid liquid and waste basic liquid is generated, and production cost reduction and environmental pollution reduction facilitated.

Description

A kind of preparation method of oligomeric galactose

Technical field

The present invention relates to a kind of preparation method of oligomeric galactose, be specifically related to desalting method in oligomeric galactose saccharifying, belong to sugared industrial technical field.

Background technology

Oligomeric galactose (GOS) is the oligosaccharides of 1-4 galactosyl on the galactosyl side of lactose molecule connects.The foundation of infant's intestinal microflora relies on the oligomeric galactose component in breast milk to a great extent.The oligomeric galactose not still multiplicaiton factor of bifidus bacillus in enteron aisle, also has and improves metabolism of fat, promotes the effects such as calcium absorption.Oligomeric galactose product on current domestic and international market all synthesizes with biological enzyme substantially.

First adopt enzymatic production in oligomeric galactose production process, the crude enzyme liquid utilizing fermentation to produce afterwards and lactose carry out enzyme reaction.In crude enzyme liquid, itself is containing a large amount of salt ions, constantly regulates PH thus to increase a large amount of salt ions in the process of enzyme reaction simultaneously.In oligomeric galactose process, conductance generally can reach more than 5000us/cm.The existence of salt ion causes conductance superelevation, causes the increase of product purity reduction and ash content simultaneously.Therefore, in later stage treating process, carry out desalination just seem particularly necessary.

It is generally adopt ion-exchange-resin process to carry out desalination that oligomeric galactose produces upper desalination reduction conductance.General in the production process of sugar products, from the conductance of the general charging feed liquid of sequence of handing at below 1000us/cm, and in oligomeric galactose production process, saccharification terminates the general 5000u/cm of rear conductance, more than 10000us/cm time indivedual.Therefore, for oligomeric galactose is produced, the shortcoming adopting ion-exchange-resin process to carry out desalination is that product loss is large, and acid and alkali consumption is large, cost is high.The regeneration ring festival-gathering of resin simultaneously produces a large amount of spent acid and waste lye, causes the pollution of environment.

Film is the material with selective separation function.The material of film can be divided into macromolecular material and the large class of inorganic materials two.Macromolecular material mainly contains cellulose family, poly-maple class, polyamide-based, polyolefine, fluorinated etc.; Inorganic materials mainly contains pottery, metal, glass, molecular sieve etc.According to the difference (or aperture) of its molecular weight cut-off, film can be divided into microfiltration membrane, ultra-filtration membrane, nanofiltration membrane and reverse osmosis membrane.

Nanofiltration membrane is the functional semi-permeable membranes of one allowing solvent molecule or some low molecular weight solutes or low price ion permeable.The aperture of nanofiltration membrane at more than 1nm, general 1-2nm.Retain organic molecular weight and be approximately about 150-500, the ability retaining solvability salt is between 2-98%, to the desalination of monovalent anion salts solution lower than high-valence anion salts solution.Be used to organism and the colourity of removing surface water, remove underground water hardness, part removes solvability salt, fruit juice concentrate and the useful matter etc. be separated in medicine.

Summary of the invention

Summary of the invention

The present invention is directed to the deficiencies in the prior art, optimize and utilize nanofiltration membrane to the method for carrying out desalination in oligomeric galactose production process.

The technical solution used in the present invention is:

A desalting method in oligomeric galactose preparation process, comprises the following steps:

1) fermentation enzyme

(1) will the inclined-plane seed of Bacillus circulans be preserved, be inoculated in LB solid medium, cultivate 12-24h for 30-33 DEG C;

(2) the inclined-plane seed activated is transferred in LB liquid nutrient medium, proceeds in LB liquid seed culture medium after 30-33 DEG C of 4-8h shaking culture.30-33 DEG C of 4-8h shaking culture, obtains seed liquor;

(3) seed liquor is proceeded in fermented liquid cultivate, obtain fermented liquid.Culture condition is: culture temperature 30-33 DEG C, obtains the crude enzyme liquid containing beta-galactosidase enzymes after incubation time 30-50h.

2) enzyme reaction

β-tilactase is proceeded to lactose solution enzymatic conversion reaction, and reaction conditions is: concentration of substrate 20-55%, temperature 30-55 DEG C, PH5.0-7.0, enzyme concentration 50-500u/g* lactose.

3) to go out enzyme and decolouring

Add feed liquid dry weight 0.1-5% gac, feed temperature is elevated to 70-100 DEG C, insulation 10-30 minute, then removes employing ceramic membrane gac.

4) nanofiltration desalination: adopt molecular weight to be that the daltonian nano-filtration membrane equipment of 150-500 carries out filtration desalination, collects trapped fluid and carries out lower procedure.

5) from friendship

Trapped fluid after nanofiltration desalination reduces conductance through ion exchange resin, is: concentration 30% conductance 0-100us/cm from friendship requirement.

6) concentrated

Vacuum concentration, obtains the oligomeric galactose that syrup concentration is 70-80%;

Preferably, enzyme concentration 50-60u/g* lactose;

Preferably, gac addition is feed liquid dry weight 2-3%.

beneficial effect

1, the present invention adopts method simple, without phase transformation and chemical reaction, and safety, reliability is high;

2, method provided by the invention first carrying out thick desalination and remove most salt ion by the mode that nanofiltration is filtered and then carry out carrying out smart desalination from friendship before handing over.This method reduce the loss of soda acid, reduce the generation of spent acid solution and waste lye, be conducive to reducing the destruction for environment.

Embodiment

For making the present invention easier to understand, set forth specific embodiments of the invention further below, but institute of the present invention protection domain is not limited thereto.β-tilactase in following examples is that Bacillus circulans CGMCCNo.8864 fermentation obtains.

embodiment 1

One, fermentation enzyme

(1) will the inclined-plane seed of Bacillus circulans be preserved, be inoculated in LB solid medium, cultivate 12-24h for 30-33 DEG C;

(2) the inclined-plane seed activated is transferred in LB liquid nutrient medium, proceeds in LB liquid seed culture medium after 30-33 DEG C of 4-8h shaking culture.30-33 DEG C of 4-8h shaking culture, obtains seed liquor;

(3) seed liquor proceeded in fermented liquid and cultivate, 30-33 DEG C of incubation time 30-50h, obtains fermented liquid;

(4) fermented liquid carried out micro-filtration or centrifugally remove thalline, obtaining liquid β-tilactase.

Two, enzyme reaction

100 grams of lactose are dissolved in water, are adjusted to concentration 45%, 95-100 DEG C insulation 20min.Add β-tilactase according to enzyme concentration 50u/g* lactose, regulate PH5.5-6.0,40 DEG C of reaction 100h.

Three, decolouring and desalination

Add 4 grams of gacs and be warming up to 90 DEG C, insulation 30min.Adopt filtering accuracy to be that the nanofiltration membrane of molecular weight 200Da is filtered after ceramic membrane filter removal activity charcoal, collect trapped fluid.Feed liquid reduces conductance through ion exchange resin, is: concentration 30% conductance 0-100us/cm from friendship requirement.Feed liquid is concentrated into 75%, obtains concentration 75%, the oligomeric galactose syrup that content is greater than 57%.

embodiment 2

One, fermentation enzyme

(1) will the inclined-plane seed of Bacillus circulans be preserved, be inoculated in LB solid medium, cultivate 12-24h for 30-33 DEG C;

(2) the inclined-plane seed activated is transferred in LB liquid nutrient medium, proceeds in LB liquid seed culture medium after 30-33 DEG C of 4-8h shaking culture.30-33 DEG C of 4-8h shaking culture, obtains seed liquor;

(3) seed liquor proceeded in fermented liquid and cultivate, 30-33 DEG C of incubation time 30-50h, obtains fermented liquid;

(4) fermented liquid carried out micro-filtration or centrifugally remove thalline, obtaining liquid β-tilactase.

Two, enzyme reaction

1 ton of lactose is dissolved in water, is adjusted to concentration 40%, 95-100 DEG C insulation 20min.Add β-tilactase according to enzyme concentration 100u/g* lactose, regulate PH5.5-7.0,45 DEG C of reaction 120h.

Three, decolouring and desalination

Add 40Kg gac and be warming up to 70-80 DEG C, insulation 30min.Ceramic membrane filter removal activity charcoal, feed liquid after filtration precision is that the daltonian nanofiltration membrane of molecular weight 300 is filtered, and collects trapped fluid and reduces conductance through ion exchange resin, is: concentration 30% conductance 0-100us/cm from friendship requirement.Use multiple-effect evaporator by feed liquid vacuum concentration to 70%, obtain concentration 70%, the oligomeric galactose syrup that content is greater than 57%.

Claims (5)

1. the desalting method in oligomeric galactose preparation process, is characterized in that, said method comprising the steps of: lactose-dissolve-add enzyme reaction-enzyme decolouring-nanofiltration desalination of going out-and from friendship-concentrated-high-purity oligomate syrup.

2. enzyme according to claim 1, for having the β-tilactase of transglycosylation.

3. production method as claimed in claim 1, it is characterized in that, in described nanofiltration desalination step, the filtering accuracy of nanofiltration membrane is 150-500 dalton.

4. enzyme according to claim 1, prepare through following steps:

(1) will the inclined-plane seed of Bacillus circulans be preserved, be inoculated in LB solid medium, cultivate 12-24h for 30-33 DEG C;

(2) the inclined-plane seed activated is transferred in LB liquid nutrient medium, proceeds to after 30-33 DEG C of 4-8h shaking culture in LB liquid seed culture medium,

30-33 DEG C of 4-8h shaking culture, obtains seed liquor;

(3) seed liquor proceeded in fermented liquid and cultivate, 30-33 DEG C of incubation time 30-50h, obtains fermented liquid;

(4) fermented liquid carried out micro-filtration or centrifugally remove thalline, obtaining liquid β-tilactase.

5., according to claim 1, described enzyme is by Bacillus circulans CGMCCNo.8864 fermentation enzyme.