KR910007613B1 - Method for producing of l-lysine - Google Patents

Abstract

A process for preparing L-lysine by continuous concn. and crystallization comprises: (a) adjusting the culture broth contg. lysine to pH 2.5 with H2SO4; (b) absorbing it into cation exchange resin, D iason SK-1B resin; (c) washing the resin with desalting water; (d) dissoluting it with 2N-ammonium hydroxide to obtain the soln. contg. high density lysine; (e) decoloring the obtd. soln. and preconcentrating; (f) continous concentrating it and crystallizing to obtain the final product. The recovery rate of lysine from the culture broth is about 90%.

Description

Method for preparing L-lysine by continuous concentration and crystallization

The present invention relates to a method for continuously concentrating and crystallizing a lysine fermentation broth, and more particularly, by adsorbing a lysine fermentation broth to a cation exchange resin (Diaion SK-1B, Duolite C20N), and eluting the high concentration portion obtained by elution. The present invention relates to a method for producing L-lysine for continuous crystallization while adding hydrochloric acid.

L-lysine is a kind of essential amino acid widely used for feed or medicine, and has been industrially produced by direct fermentation using microorganisms. In this conventional method, a fermentation broth is obtained by using alone or a mixture of sugarcane, beet, and high text molasses using Brevibacterium or Corynebacterium strains, so that many impurities including cells and pigments are contained. In order to adsorb only the lysine component in the fermentation broth to the resin, the pH was adjusted to 1.5-4.0 with hydrochloric acid or sulfuric acid. At this time, the cells in the fermentation broth may be removed depending on the need, but if not removed, it is convenient to adsorb the resin upstream.After the adsorption, the resin is washed with deionized water to remove the cells and impurities in the resin layer. Elution with 2N ammonium hydroxide recovered the high concentration portion of lysine.

Conventionally, the high concentration of lysine is concentrated to deammonia, and then pH is adjusted with hydrochloric acid to make hydrochloride and decolorized with activated carbon, and then the decolorized liquid is further concentrated in crystal tube and crystallized to recover lysine hydrochloride. Due to the increase in the size and quantity of the crystal tube, the cost of equipment is increased, and technical difficulties and yields are reduced due to the complicated process. .

Therefore, the present invention improves the economical efficiency of the device and energy efficiency, and is a method that can improve yield, increase discoloration power, and greatly reduce the size and quantity of crystal tube and greatly reduce energy consumption. .

The present inventors have observed that crystallization is not easy in an alkaline state with high pH of the final concentrate, and that crystals are easily formed when cooling with hydrochloric acid added to the concentrate. The present invention has been completed by developing a method that can be carried out continuously.

The present invention will be described in more detail below.

After the adsorption of the lysine fermentation broth, the high concentration portion recovered by removing the cells and impurities was directly passed through a decolorizing resin (Diaion HPA-25) to decolorize.

The decolorization solution passed through the resin column showed a recovery rate of lysine of 99.5% or more and a decolorization rate of 60% or more.

TABLE 1

* Volume = Drain × Resin Volume (RV)

The decolorized solution had an alkaline pH of 10.7-11 and a lysine concentration of 72-46 g / ι without hydrochloride. After preliminarily concentrating the alkaline decolorizing solution in a free base state in a multi-utility condenser at about 360-440g / ι, and concentrating again in a continuous single-tube condenser to obtain a concentration of 760-840g / ι, and then into a continuous crystal tube. Transfer to crystallization by cooling while adding hydrochloric acid to pH 5.0. At this time, since the concentration and crystallization is performed continuously, it is possible to reduce the size and quantity of the conventional crystal tube.

In the continuous condenser, it is important to concentrate while maintaining the concentration of the condensate, so the concentration of 785 g / ι, the evaporation at a certain temperature, and the specific vacuum level must be calculated in advance. The concentration, feed rate and discharge rate of the final concentrated liquid should be calculated to achieve a perfect steady state balance.

The crystallization rate is determined according to the concentration of the final concentrate. As shown in Table 2, it was confirmed that the working condition was optimal at the lysine concentration of 785 g / ι in the free base state. In the above case, there was a problem in that the crystallization rate was excessively high and a lot of load was applied to the stirring device.

TABLE 2

The present invention is explained in more detail in the following examples.

Example 1

After adjusting 1Kι of lysine fermentation broth obtained from sugarcane waste molasses to pH 2.5 with sulfuric acid, it was adsorbed upstream to 1Kι of cation exchange resin (D iaion SK-1B resin; Mitsubishi, Japan) previously regenerated in ammonium form. . Subsequently, the cells were washed with demineralized water to remove remaining cells in the resin layer, and then eluted with 2N ammonium hydroxide to collect a high concentration of lysine. The solution was collected in a resin tower filled with 16 탈 of decolorizing resin, and as a result, 850 탈 of decolorizing solution was collected. The decolorization rate was 68%.

Pre-concentrate this decolorizing solution to 393g / ι, which is a hydrochloric acid-free concentration in the concentration tube, and use it as a feed solution of the continuous concentration tube to maintain the concentration to 785g / ι, and add it to the crystal tube and adjust pH to 5.0 with hydrochloric acid. Cooling crystallization was performed.

As a result of the crystallization, the slurry was separated by a centrifugal separator. As a result, 57 kg of the first wet product and 65 ι of mother liquor were obtained.

Since this primary mother liquor contained 26.3 Kg of lysine hydrochloride, the solution was separated by crystallization while concentration in a batch again, and as a result, 19.4 Kg of the secondary wet product and 30 ι were obtained. This secondary mother liquor was circulated to the fermentation broth and used again. The primary and secondary wet products were combined and dried to obtain 62 kg of dry product with 99% content.

The recovery rate from the fermentation broth was 90% when reprocessing the secondary mother liquor.

Claims (1)

After purifying the lysine fermentation broth in a conventional manner, L- lysine manufacturing method characterized in that the crystallization in the crystal tube while adding hydrochloric acid to the concentrate obtained by continuous concentration up to 760-840g / ι in the free base state.