KR100318755B1 - Process for producing ethanol with high concentration from wood hydrolysate using low-temperature sterilization - Google Patents

Abstract

The present invention relates to a method for producing a high concentration of ethanol from wood-based saccharification liquid using a pasteurization method, the purpose of which is a general method using low-temperature sterilization instead of the high-temperature sterilization used in the existing process in the production of ethanol from wood-based biomass In addition to obtaining more than the ethanol concentration that can be produced by the present invention to provide a high productivity batch and continuous wood-based ethanol production process.

Providing the present invention can produce ethanol at high concentration and high productivity, thereby reducing the cost of fermentation and purification during the entire ethanol production process. According to the batch and continuous fermentation of the present invention, ethanol concentration and productivity are respectively 67 g / L, 1.0 g / L / h, and 76.9 g / L, 16.9 g / L / h could be achieved.

This method is environmentally and economically because it can produce ethanol at high concentration and productivity through environmentally friendly biological methods using wood-based biomass such as wood and municipal organic waste, which are abundant in the world and are important resources in the environment. It is a process with advantages.

Description

Process for producing ethanol with high concentration from wood hydrolysate using low-temperature sterilization

The present invention relates to a high-concentration ethanol production process from lignocellulosic Hydrolyzate with low temperature myeolgyunbeop, described in detail gritty wood, waste wood, in yeast Saccharomyces from the glucose present in the saccharification mixture urban organic waste, my process serenity non-zero (Saccharomyces cerevisiae) in the production of ethanol, by the low temperature sterilization different from the conventional sterilization method to suppress the production of various toxic substances harmful to microorganisms generated from cellulosic biomass and the yeast system A method for producing ethanol at high concentration from biomass.

Woody biomass has recently attracted interest in producing useful substances such as ethanol using these materials due to their environmental friendliness and inexpensive and abundant existence (Lynd et al., Science, 251: 1318). -1323 (1991)).

In order to produce useful substances from woody biomass using microorganisms, it is necessary to pretreat woody biomass with sugars in the form of microorganisms such as glucose.

However, pretreatment of wood-based biomass produces toxic substances that are bad for the growth of many microorganisms.

In general, in the case of producing useful substances such as ethanol using microorganisms, the higher the concentration of useful substances such as ethanol produced from microorganisms, the more economical the economical cost is.

However, when using wood-based biomass, these toxic substances could not produce high concentrations of useful substances such as ethanol.

Thus, there have been studies to reduce the toxicity by chemically treating these toxic substances with activated carbon, lime, etc. (Parajo et al., Bioresource Technol., 57: 179-185 (1996), Rivard et al., Appl. Biochem.Biotechnol., 57-58: 183-191 (1996)).

However, these chemical treatments cause other problems, such as separation of additive materials, and the processing capacity varies depending on the materials and methods, so that these problems can be solved in order to economically produce ethanol from woody biomass. Development of the method was needed.

In addition, in order to economically produce general-purpose chemicals such as ethanol from woody biomass, not only the produced ethanol concentration but also the productivity of the fermenter is very important, and therefore, it is necessary to develop an efficient fermentation process.

It is an object of the present invention to obtain ethanol concentration that can be produced by a general method using low temperature sterilization instead of high temperature sterilization in the conventional process in producing ethanol from woody biomass to solve the above problems. It is to provide a batch and continuous ethanol fermentation process capable of producing ethanol with high productivity.

1 is a graph showing the ethanol fermentation capacity from the wood-based saccharification solution at high temperature sterilization (121 ℃).

Figure 2 is a graph showing the ethanol fermentation capacity from the wood-based saccharification solution at high temperature sterilization (121 ℃) after activated carbon treatment.

Figure 3 is a graph showing the ethanol fermentation capacity (a: glucose concentration, b: ethanol concentration) from the wood-based saccharification solution at low temperature sterilization (60 ℃).

Figure 4 is a graph showing the ethanol fermentation capacity (a: glucose concentration, b: ethanol concentration) from the wood-based saccharification solution at low temperature sterilization (60 ℃) after activated carbon treatment (0.2 g activated carbon / g glucose).

5 is a schematic diagram of an internal filtration reactor system for continuous fermentation.

Figure 6 is a graph showing the continuous ethanol fermentation capacity using the internal filtration reactor from the saccharified liquor system at low temperature sterilization (60 ℃).

<Description of the symbols for the main parts of the drawings>

(1): Fermenter equipped with internal filter module

(2): motor

(3): Pressure gauge

(4): backflushing device

(5): saccharified liquid storage tank

(6): fermentation broth storage tank

(7): surplus liquid storage container (bleed chamber)

Embodiments of the present invention for achieving the object as described above and to eliminate the drawbacks of the prior art will be described in detail in connection with the configuration and operation of the accompanying drawings.

The present invention is a method for producing ethanol by reacting glucose and microorganisms in a saccharified solution by pretreatment and enzymatic saccharification of wood-based biomass including waste wood and municipal organic waste,

Batch method of fermenting and producing ethanol by inoculating saccharomyces cerevisiae, an industrial strain, into glucose in the glycated saccharified solution after the step of reducing toxic substances by sterilizing the saccharified liquid,

The present invention also provides a method for producing ethanol by reacting glucose and microorganisms in saccharified solution by pretreatment and enzymatic saccharification of wood-based biomass including waste wood and municipal organic waste.

Batch method of fermenting and producing ethanol by inoculating saccharomyces cerevises, an industrial strain, into the glucose in the saccharified liquid after the step of reducing toxic substances by using low temperature sterilization method and activated carbon treatment at the time of sterilization of the saccharified liquid;

The present invention also provides a method for producing ethanol by reacting glucose and microorganisms in saccharified solution by pretreatment and enzymatic saccharification of wood-based biomass including waste wood and municipal organic waste.

After sterilization of the saccharified solution, the toxic substance is reduced by using low temperature sterilization method, and the glucose in the saccharified solution is inoculated with Saccharomyces cerevise, an industrial strain, and the ethanol is continuously fed using a fermenter equipped with an internal filter module. It consists of a method of production.

Hereinafter, the present invention will be described in detail with reference to Examples.

Example 1

: Production of high concentration ethanol from woody biomass by low temperature sterilization (batch)

The strain used in the present invention was Saccharomyces cerevisiae, an industrial strain, and the strain was distributed from Seoyoung.

The composition of the medium used for inoculation was based on 0.3% yeast extract, 0.3% malt extract, 0.5% bacto peptone, and 2% glucose. Was used.

The wood-based saccharification liquid used was first pulverized oak for 15 minutes at 215 ° C. using an 8L steam bomber, and 20 units of filter paper activity and 30 units of betaglucose using a 30L reactor. Cellulase and betaglucosidase enzyme adjusted to have a β-glucosidase activity were glycosylated at 50 ° C. for 3 days, and then concentrated to a desired glucose concentration using a vacuum evaporator.

Ethanol fermentation using wood-based saccharification concentrate was carried out in a shaking incubator using a 100 ml flask containing 25 ml of concentrate.

The operation was performed at 30 ° C. and 150 rpm and the initial pH was constantly adjusted to 5.0.

The fermentation used only the explosive saccharification liquid diluted with the appropriate glucose concentration indicated in the result without the addition of nutrient medium.

1 is a graph showing the ethanol fermentation capacity from the saccharified solution prepared at the high temperature sterilization (121 ℃) of the saccharified solution prepared as described above. The amount of sugar used up to about 90g / L, including the stock solution, was consumed according to the high inoculum dose, and fermentation was not performed at 100g / L or more.

This is due to fermentation inhibitors during the pretreatment process (Palmqvist et al., Enzyme Microb. Technol., 20: 286-293 (1997)).

Figure 2 is a graph showing the ethanol fermentation capacity from the wood-based saccharification solution when the saccharified solution at high temperature sterilization (121 ℃) activated carbon treatment, there was some effect when treated with activated carbon which is often used to reduce the effects of inhibitors Fermentation did not occur at the glucose concentration of 100 g / L or more of the wood-based saccharified solution.

However, as a result of the sterilization of the saccharified solution at low temperature sterilization (60-70 ° C., 30-120 minutes) in FIG. 3 (a, b), the fermentation was not performed at high temperature sterilization (121 ° C., 15 minutes). It was shown that normal fermentation was possible up to 140 g / L as well as substrate.

That is, Figure 3 (a, b) is a graph showing the ethanol fermentation capacity (a: glucose concentration, b: ethanol concentration) from the wood-based saccharification liquid at low temperature sterilization (60 ~ 70 ℃, 30 to 120 minutes), especially 140 Fermentation was almost complete after 2 days when inoculated with 20% (v / v) of Saccharomyces cerevises when using g / L substrate, and the ethanol concentration and productivity of fermentation were 67g / L and 1.0, respectively. g / L / h.

Figure 4 is a graph showing the ethanol fermentation capacity (a: glucose concentration, b: ethanol concentration) from the wood-based saccharification when activated carbon treatment (0.2 g activated carbon / g glucose) after low temperature sterilization (60 ~ 70 ℃), substrate concentration 170 Even when g / L was used, a lag period of 100 hours or more existed, but the fermentation was more effective than the conventional high temperature sterilization method, and the addition of activated carbon treatment was more effective.

Example 2

: High concentration and high productivity ethanol production method in fermenter equipped with internal filter module using low temperature sterilization method (continuous type)

FIG. 5 is a schematic diagram of a fermenter system equipped with an internal filter module for continuous fermentation. In Example 2, continuous fermentation is performed in a fermenter equipped with an internal filter module using low temperature sterilization as compared to the batch illustrated in Example 1. Was carried out to observe the effect of improving the productivity of ethanol.

The volume of the fermentation broth of the used 3L fermenter (1) is 1.5L, and only the wood-based saccharification solution containing 100-180 g / L of glucose was used as a new medium to be supplied to the fermentor during continuous fermentation.

The filter module mounted inside the fermenter 1 is composed of 13 cylindrical ceramic tubes having an inner radius, an outer radius, and a height of 8, 11 and 80 mm, respectively, and has a filtration surface area of 360 cm ² .

The material of the filter used was ceramic, the pore size (pore size) is composed of less than 0.3㎛ and the filtration surface area is disposed inside the fermentation broth.

Symbol (2) is a motor for stirring the fermenter, (3) is a pressure gauge for measuring the negative pressure of the liquid exiting the filter module, (4) backflushing which blows the filter layer upside down when the filter module is blocked. The apparatus (5) is a saccharification liquid storage tank, (6) is a fermentation liquid storage tank which is a product, and (7) is a surplus liquid storage container which arises when backflushing etc. are performed.

The high concentration of saccharified liquid (100 g / L to 180 g / L) stored in the saccharified liquid storage tank (5) was introduced into the fermenter (1) through a pump and stirred by a motor (2) to ethanol by Saccharomyces cerevisiae. Fermented. At the same time, the liquid in the fermenter 1 is continuously discharged into the fermentation broth 6 through the filter module, and the Saccharomyces cerevisiae cells and solids grown therein are filtered in the filter module.

If the continuous fermentation is continued, the solids are deposited on the filter module, so that the pressure gauge (3) falls to the negative and the discharge of the fermentation broth becomes difficult. The fermentation broth is backwashed by periodically operating the backflushing device (4). Should be easy to discharge.

Continuous fermentation was first performed in a batch fermentation, and then the substrate was consumed and operated at a dilution rate of 0.22 h ⁻¹ or more.

The fermentation was carried out at 30 ℃, in order to maintain high activity of the cells in the fermenter was supplied with air at 0.5 ~ 1.0vvm and yeast cells in the fermentation broth were internal filtration.

6 is a graph showing the ethanol fermentation capacity using the fermenter equipped with an internal filter module from the wood-based saccharified solution at low temperature sterilization (60 ℃), a continuous fermentation from the wood-based saccharified solution sterilized by using a fermenter Results For saccharified solutions containing 137 g / L and 180 g / L of glucose, the cell concentration and ethanol concentration were 1.4 × 10 ⁹ cells / ml, 1.5 × 10 ⁹ cells / ml, 58.8 g / L, and 76.9 g / L, respectively. As a result, very high cell concentration and ethanol concentration were obtained compared to the conventional method.

Ethanol production yield was 0.43 g ethanol / g glucose.

In addition, the ethanol productivity at this time is up to 16.9 g / L / h, the value in the batch culture illustrated in Example 1 (1.0 g / L / h) or the value in the fermenter by high temperature sterilization (6.7 g / L / h, See: Lee et al., Korean J. of Chem, Eng., 13: 453-456 (1996)).

As in batch cultivation using low temperature sterilization method, the contamination problem by low temperature sterilization did not occur even in continuous culture using a fermenter equipped with an internal filter module, which was a very efficient process for producing useful substances such as ethanol using wood-based saccharification liquid. The applications for ethanol production from wood and municipal organic wastes have been highly economical, with high productivity.

The present invention is not limited to the above-described specific preferred embodiments, and various modifications can be made by any person having ordinary skill in the art without departing from the gist of the present invention claimed in the claims. Of course, such changes will fall within the scope of the claims.

As described in detail above, the present invention provides a method for producing high concentration ethanol from woody biomass using low temperature sterilization.

In addition, according to the present invention, the high-density wood-based saccharification solution of 180g / L glucose concentration which cannot be fermented using the existing high-temperature sterilization method can not be obtained by the conventional method using a continuous fermenter equipped with low-temperature sterilization method and an internal filter 76.9g Ethanol concentration of / L and ethanol productivity of 16.9 g / L / h were obtained.

Therefore, the present invention minimizes the effects of toxic substances generated during pretreatment, saccharification and sterilization of wood based biomass, which are essential for producing useful materials from wood based biomass using microorganisms, by minimizing low temperature sterilization and high productivity fermentation. It will contribute to the industrialization of the process of producing useful substances, including ethanol, using microorganisms from cheap and abundant woody biomass.

Claims (7)

In the method of producing ethanol by reacting glucose and microorganisms in the pretreatment and saccharification liquid of wood-based biomass including waste wood and municipal organic waste, After sterilization of the saccharified solution, the pasteurization method is characterized by a batch method of fermenting and producing ethanol by inoculating saccharomyces cerevises, an industrial strain, into the glucose in the saccharified solution after reducing the toxic substances. Method for producing high concentration ethanol from the wood-based saccharified solution In the method of producing ethanol by reacting glucose and microorganisms in the pretreatment and saccharification liquid of wood-based biomass including waste wood and municipal organic waste, After sterilizing the saccharified solution, it is a batch method of fermenting and producing ethanol by inoculating saccharomyces cerevise, an industrial strain, into the glucose in the saccharified solution after going through steps to reduce toxic substances by using low temperature sterilization and activated carbon treatment. Method for producing high concentration ethanol from wood-based saccharified solution using low temperature sterilization In a method of producing ethanol by reacting wood-based biomass including waste wood and municipal organic waste with glucose in a pretreatment and saccharification liquid, After sterilization of the saccharified solution, the process of reducing the toxic substances using low temperature sterilization method is followed by inoculating the glucose in the saccharified solution with Saccharomyces cerevisiae, an industrial strain, and using a fermenter equipped with an internal filter module. Method for producing high concentration ethanol from wood-based saccharification liquid using low temperature sterilization method characterized in that the production method The method according to any one of claims 1 to 3, The low temperature sterilization method is a method for producing a high concentration of ethanol from the wood-based saccharification solution using a low temperature sterilization method, characterized in that sterilization of the saccharified solution at 60 ° C to 70 ° C for 30 to 120 minutes. The method of claim 3, wherein Continuous ethanol production method using a fermenter equipped with an internal filter module is a continuous fermentation is carried out by batch fermentation first, then all the substrate is consumed, and then fermentation by supplying a medium while operating at a suitable dilution rate of 0.22 h ^-1 or more Method for producing a high concentration of ethanol from wood-based saccharification solution using a pasteurization method, characterized in that to perform the air, 0.5 ~ 1.0 vvm in order to maintain high activity of the cells in the fermentor, and internal filtration of the yeast cells in the fermentation broth. The method of claim 5 The medium is a method for producing a high concentration of ethanol from the wood-based saccharification solution using a pasteurization method, characterized in that using only wood-based saccharification solution containing less than 180 g / L of glucose. The method of claim 5, The filter module mounted inside the fermenter is composed of a cylindrical porous ceramic tube (pore size 0.3 micron or less), and the filtration surface area is disposed in the fermentation broth.