JPS61185180A - Immobilized bioreactor for alcoholic fermentation - Google Patents

Abstract

PURPOSE:To keep high volume efficiency of an immobilized bioreactor, to facilitate the removal of generated gas, and to prevent the loss of immobilization carrier, by attaching common gas-liquid separation zone to the top of a coil, and separating and removing generated CO2 gas with the separation zone. CONSTITUTION:A common gas-liquid separation zone 4 is attached to the top of a coil. A number of cell-immobilization carrier particles are suspended in a reactor, and the fermentable saccharide in the raw syrup supplied from the line 1 is decomposed to produce ethanol. The separation of the generated gas bubbles can be carried out surely in improved efficiency by the use of the gas- liquid separation zone, and the loss of the immobilization carrier accompanied by the fermentation liquid flow in the line 5 can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an immobilized bioreactor for alcohol fermentation, and in particular to an immobilized bioreactor with continuous fermentation.

(Conventional technology) Alcohol production by fermentation has traditionally been developed mainly in the so-called brewing industry, but in recent years, based on this technology, it has been possible to produce alcohol from so-called biomass such as agricultural products (molasses, sweet potatoes, corn, sugar cane, etc.). The so-called "gasohol project" is being planned, in which fuel alcohol (and <K ethanol) is produced and used by mixing it with conventional fuels such as gasoline.

This has already been achieved in countries such as Brazil, where 80% of ethanol can be produced.
K/scale plants are also in operation, and there are signs that this plan will become more popular in developing countries, such as Southeast Asia.

Traditionally, the fermentation process developed mainly in the brewing industry requires large-capacity fermenters in multiple stages and is a batch process, so the ethanol productivity (ethanol production per unit capacity of fermenter, per unit time) is at most 1. ~2 kg ethanol/m”/h, and an improved bacterial cell recirculation semi-continuous fermentation method (Mal
Even with the e-Boinot method, it is no more than 4 kg/mj/hK.

On the other hand, although it has not yet been put to practical use, various new bioreactors have been proposed to overcome the drawbacks of these conventional methods, such as immobilization of bacterial cells (the immobilization method uses alginate powder). Reactors (i.e., immobilization bioreactors) that carry out continuous fermentation using various methods (including the comprehensive method) have been developed one after another, but it cannot be said that they have been established yet.

(Problems that the invention seeks to solve) The immobilization bioreactor Kd proposed in the above-mentioned current situation has the following basic problems. (1) As a result of alcohol fermentation, a large amount of COl is produced as a by-product.
Due to the gas, the interior of the reactor is in a strong mixing state, and therefore it is difficult to bring the reactor mixing type close to the "extrusion flow system" K, which hinders improvement in fermenter volumetric efficiency (=ethanol productivity). (The current immobilized bioreactor mixing system is a nearly complete mixing system, and compared to the extrusion flow system, the same reaction yield = ethanol production!
/ Obtaining sugar substrate consumption requires an extremely long reaction time, resulting in low alcohol productivity = volumetric efficiency. ) (2) Because the by-product CO2 gas bubbles are "fermentation products," they are extremely fine and difficult to remove from the reactor internal liquid. (objects with immobilized bacteria) are likely to flow out together with the fermentation liquid (the amount of immobilized carriers in the reactor gradually decreases, making it difficult to maintain a steady state of continuous fermentation), and ■ microbubbles adhere to the surface of the immobilized carriers. (For IIK, the immobilized carrier is packed in the reactor at a high density and the raw sugar is The liquid is flowed from above or below, trying to maintain the extrusion flow system as much as possible.
There is also a ``packed bed reactor,'' but this method tends to cause uneven flow within the beam reactor (local accumulation of produced ethanol and CO causes deactivation of the carrier), and the generated CO and gas tend to cause uneven flow in the reactor. However, in this method, where the carrier packing density is extremely high, the shearing force on the immobilized carrier is also large.
This method is not often used in practice due to problems such as the possibility of damage to the immobilization carrier.

The present invention aims to overcome the problems of these conventional methods and provide a bioreactor with high productivity and high stability.

(Means for Solving the Problems) The present invention aims to achieve the above-mentioned objective by bringing the mixing type in the reactor as close as possible to the extrusion flow system, even though a large amount of CO and gas are generated in continuous fermentation. This is achieved by maintaining efficiency (ie, high alcohol productivity), facilitating the removal of generated gas, and preventing the immobilized carrier from flowing away (ie, maintaining high stability).

That is, the present invention provides an immobilized bioreactor for alcohol production by continuous fermentation, (1) having a structure of a horizontal corrugated tube type (the pitch rate of the corrugated tube can be set arbitrarily), (2) on the upper part of this corrugated tube, The present invention relates to an immobilized bioreactor characterized in that a common gas-liquid separation zone is provided to separate and eliminate generated CO2 gas.

FIG. 1 is a diagram showing an embodiment of the immobilization bioreactor of the present invention. This bioreactor is a horizontal serpentine type bioreactor as shown in Figure 1 (the number of pitches can be set arbitrarily based on reaction kinetic characteristics, etc.). The higher the concentration dependence, the higher the reactor volumetric efficiency, and the more compact the reactor is needed to maintain the specified ethanol production amount, A common gas-liquid separation zone 4 is provided at the top of the flexible pipe.゛In Fig. 1, 1 is the immobilization bioreactor main body, 2 raw sugar liquid lines, 3 is the generated CO2 gas line, 5 is the cape liquid line, 6 is the immobilization carrier, 7 is the generated bubbles, 8 is a separation and purification process.

(Function/Effect) A large number of bacterial cell immobilized carriers 6 are suspended in this reactor, and fermentable carbohydrates in the raw sugar solution supplied from line 1 are decomposed to produce ethanol.

There are various methods for immobilizing bacterial cells, such as entrapping method and adsorption method.
Common and well-known materials such as K-carrageenan and Pvum (polyvinyl alcohol) are used, and in the adsorption method, common materials such as activated alumina and activated carbon are used.

By employing such a flexible pipe type, the mixing mode within the reactor is close to the extrusion flow system, and the volumetric efficiency is significantly improved. In other words, a smaller capacity fermenter can be used to maintain the same amount of alcohol produced, or a larger amount of alcohol can be produced with the same capacity fermenter.

In addition, by making this horizontal, there is no need to increase the height of the reactor, which is advantageous in terms of eliminating generated gas (the higher the height of the reactor, the more the bubbles generated will be Residence time inside becomes longer, and K<
) 0 In addition, a common gas-liquid separation seam 74 is installed at the top of the flexible pipe.
By providing this, the generated gas bubbles can be removed more efficiently and reliably, and the accompanying outflow of the immobilized carrier due to the fermentation liquid in line 5 can also be prevented, and the amount of immobilized carrier retained in the reactor can be stably maintained. This increases stability.

(Example) The immobilization bioreactor of the present invention shown in FIG. 1 and the conventional immobilization bioreactor shown in FIG.
(The tank capacity is the same at 11) was prototyped, and the ethanol productivity of both was compared to confirm the effectiveness of the present invention.

In Figure 2, the same symbols as in Figure 1 have the same meaning as in Figure 1, and 1
1 immobilized bioreactor, 12 a raw material storage tank, and 13 a raw material feed pump.

The table below shows the composition of the raw sugar solution used in one experiment.

The method for immobilizing bacterial cells was the same in both reactors and was carried out as follows.

The encapsulant is a 3-chloride aqueous solution of sodium alginate (for gelation, Oa
A spherical immobilized carrier was used, and the reactor was filled with a volume ratio of about 25%.

In addition, the pH of the fermentation liquid was 4.5, the temperature was 50°0, and the number of bacteria used was 8.
accharomyces ellipsoideus
It is 00-2.

Both reactors were operated continuously for 15 hours at a dilution rate (= stock solution flow rate/tank volume, expressed as the reciprocal of the residence time), and the ethanol productivity was compared with that of the conventional type. It was found that the productivity was approximately 1.4 to 1.5 times higher than that of the mold, and it was also confirmed that the immobilized carrier was retained extremely stably within the reactor, confirming the effectiveness of the present invention. Ta.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the reactor of the present invention, and FIG. 2 is a diagram showing a conventional bioreactor. Sub-agent: 1) Sub-agent: Ryo Hagiwara - Figure 1 Figure 2 Procedure amendment

Claims (1)

[Claims] An immobilized bioreactor for alcohol production by continuous fermentation, characterized in that the reactor is of a horizontal serpentine tube type, and a common gas-liquid separation zone for separating and eliminating generated CO_2 gas is provided at the upper part of the serpentine tube. Immobilization bioreactor.