JPS63219386A - Production of sugaralcohol - Google Patents

Abstract

PURPOSE:To produce a sugaralcohol solution to be readily purified without causing by-products, by treating yeast belonging to the genus Candida immobilized to a carrier with a mixed saccharide solution of substrate saccharide and hydrogen donor saccharide. CONSTITUTION:Yeast such as Candida tropicalis or Candida utilis, belonging to the genus Candida is cultivated and the yeast is immobilized to a ceramic carrier, a gelatinous carrier such as gelatinized polyacrylamide or gelatinized alginic acid or a polyurethane foam carrier. The immobilized yeast packed into a reactor is reacted with a mixed saccharide solution comprising a substrate saccharide such as glucose or mannose, a hydrogen donor saccharide such as glucose or galactose and a nutritive source for yeast by passing the solution through the reactor. Consequently a sugaralcohol corresponding to the substrate saccharide is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for producing sugar alcohols using immobilized yeast.

(Prior Art and its Problems) In recent years, many methods have been attempted for producing useful substances using immobilized microorganisms, and a typical example is a method for producing ethanol from glucose using yeast.

In addition, attempts to produce sugar alcohols by reducing sugars have been reported, but it has not been possible to obtain a large amount of the desired product without producing by-products.

(Means for Solving the Problem) As a result of investigating various methods for producing sugar alcohols using microorganisms, the present inventors have determined that the present inventors can reduce the Sugars that act as hydrogen donors necessary for reactions (hereinafter referred to as hydrogen-donating sugars)
The present invention has been completed based on the discovery that the amount of sugar alcohol produced can be dramatically improved by adding the sugar mixture and treating the sugar mixture with yeast immobilized on a carrier such as ceramic.

That is, the present invention involves culturing yeast belonging to the genus Cansida, immobilizing the yeast on a ceramic carrier, gel-like carrier, polyurethane foam carrier, etc., filling a reactor with the immobilized yeast, and dissolving the substrate sugar, hydrogen-donating sugar, and yeast. A sugar alcohol corresponding to the substrate sugar is obtained by retaining or passing through a sugar mixture consisting of nutritional sources while air or oxygen is aerated.

As a result of screening by the present inventors, it was found that yeasts belonging to the genus Cansida are suitable as yeasts with a high ability to produce sugar alcohols to be used in the present invention. Examples of the yeast belonging to the genus Cansida include Cansida toro and caris, Cansida euteris, and derivative strains thereof.

The culture conditions for these yeasts are similar to those for generally known fermentation of sugars. For example, the growth medium for Cansida tropicalis is 3% xylose and 0.0% yeast extract.
A medium based on 3% potassium phosphate, 1.5% potassium phosphate, 0.3% diammonium phosphate, and 0.1% magnesium sulfate is preferable, and pli 5.0. Culture at 30°C for 48 hours. It can be cultured by The cultured yeast is collected,
It is washed and subjected to the next adsorption immobilization or entrapment immobilization.

As the substrate sugar, any carbohydrate that can be assimilated by yeast can be used, but for example, pentose or hexose is preferable in order to obtain the desired sugar alcohol in good yield.
Among them, xylose, arabinose, and ribose are more preferable as substrate sugars. As hydrogen-donating sugars, pentose and hexamonosaccharides are preferred, and glucose, mannose, and galactose are more preferred; by combining one type of each of these substrate sugars and hydrogen-donating sugars, the desired sugar alcohol can be efficiently obtained. Can be done.

The method for preparing the immobilized yeast used in the present invention can be carried out in the same manner as the generally known method for immobilizing microbial cells. For example, a method for adsorbing and immobilizing yeast on ceramics is to
m, inner diameter 2c+n, height 1.5c+++ 4 to 8 cylindrical ceramics stacked, or 1g of cylindrical ceramics with the same outer diameter and inner diameter and 6 to 8 cm in height, each in a reactor for immobilization. After placing the cultured yeast in a carrier (diameter: 5 awa x height: 20 cm), the cultured yeast is injected from the top together with the medium used for culture, and the yeast cells are adsorbed and immobilized on the carrier. Furthermore, for example, when polyacrylamide is to be immobilized, acrylamide monomer, N,N'-methylenebisacrylamide, β-dimethylaminopropionitrile, and potassium persulfate are added to yeast suspended in physiological saline. In addition, entrapping immobilization is achieved by leaving it at room temperature to gel. In addition, carrageenan gels, alginic acid gels, photocurable resins, polyurethane foams, etc. can also be used as the carrier in the present invention.

To explain in detail the method for producing sugar alcohol using immobilized yeast of the present invention, for example, a culture solution obtained by culturing Cansida Toro and Callis etc. by shaking culture etc. is treated with a carrier such as ceramic by the method described above. The immobilized yeast is prepared using the method described above, and this is packed into, for example, a three-phase fluidized bed column. The sugar mixture as a reaction solution is, for example, a solution in which yeast extract, monopotassium phosphate, diammonium phosphate, magnesium sulfate, manganese sulfate, etc. are dissolved to a concentration of 0.001 to 2%, respectively, in plI3 to 5. A substrate sugar and a hydrogen-donating sugar are added to a buffer solution adjusted to . As the substrate sugar, one of glucose, mannose, galactose, xylose, arabinose, ribose,
Select one of glucose, mannose, and galactose as the hydrogen-donating sugar, and add 1 to 20% of each of these.
Dissolve the sugar in the above-mentioned buffer solution to a concentration of , and prepare a sugar mixture. The sugar mixture is heated to 25-50°C in advance, preferably 30-30°C.
The above-mentioned immobilized yeast kept at 5° C. is placed in a column filled with the yeast, and the reaction is allowed to occur while air or oxygen is aerated from the bottom of the column. This reaction can be carried out in a batch manner or in a continuous manner, for example in a batch manner, it is carried out by replacing the product liquid with a fresh sugar mixture every 24 hours. In addition, in the case of a continuous method, for example, the sugar mixture is continuously pumped into a column filled with yeast, similar to that used in the batch method, using a peristaltic pump, and the product liquid is poured from the other side of the reaction column at the same rate as the injection rate. This is done by draining. Column temperature control and sugar mixture p II:I! You can get even better results by doing one section frequently.

The actual state of the present invention will be illustrated below with reference examples and examples.

Reference example 1. An aqueous solution consisting of 3% xylose, 0.3% yeast extract, 1.5% potassium phosphate, 0.3% diammonium phosphate, and 0.1% magnesium sulfate.
．． 100 ml of the medium adjusted to 0 was placed in a 500 ml Sakaro flask, and a loopful of one strain of Cancita tropicalis IF0 061 preserved on a glucose polypeptone agar medium was inoculated.

This was cultured at 30°C for 48 hours, and the resulting yeast cells were grown in the medium for 9 hours. After washing with water, the yeast cells were suspended in the same medium as above and placed in a three-phase flow molding column. (diameter 5 marks height 20 cm) was adsorbed and immobilized on a ceramic carrier.

Example 1゜Reference Example 1.0 A three-phase fluidized bed column packed with immobilized yeast was kept at 30°C, and added with 3% xylose and 4% glucose.
%, yeast extract 0.1%, monopotassium phosphate 0.3%,
Diammonium phosphate 0°3%, magnesium sulfate 0.
A sugar mixture adjusted to PTI 4.0 was added to an aqueous solution consisting of 0.01% manganese sulfate and 0.05% manganese sulfate, and after holding for 24 hours while aerating air, the resulting solution was drawn out, and the sugar mixture was again filled and the same procedure was carried out. The operation was repeated. The amount of xylitol produced was 1.5 g/100 ml of produced liquid.

Example 2゜Example 1. Using a similar device and the same sugar mixture, the sugar mixture was continuously supplied at 8 ml/hr and the amount of xylitol produced in the effluent was measured, and it was 1.5 g/100 ml.
Product liquid and Example 1. The yield was similar.

(Effects of the Invention) According to this method, complicated by-products are not produced as in so-called fermentation methods, and a sugar alcohol solution that is easy to purify can be obtained.

Claims (4)

[Claims] (1) A method for producing a sugar alcohol, which comprises treating a sugar mixture of two types of sugars, a substrate sugar and a hydrogen-donating sugar, with yeast belonging to the genus Cansida immobilized on a carrier. (2) The manufacturing method according to claim 1, wherein the carrier is a ceramic, polyacrylamide gel, κ-carrageenan gel, alginate gel, photocurable resin, or polyurethane foam. (3) A patent claim in which the substrate sugar is any one selected from the group of glucose, mannose, galactose, xylose, arabinose, and ribose, and the hydrogen-donating sugar is any one selected from the group of glucose, mannose, and galactose. The manufacturing method described in Scope 1. (4) The production method according to claim 1, wherein the immobilized yeast treatment method is intermittent or continuous.