JPH022900A - Method for culturing anaerobes - Google Patents

Abstract

PURPOSE:To obtain anaerobes having high cellulose decomposing activity by adding cellulose and vitamin to an aq. soln. of the materials constituting organisms, and culturing the anaerobes in a culture soln. freed of dissolved oxygen in the method for obtaining anaerobes to be used in the methane fermentation for treating org. waste. CONSTITUTION:Cellulose and vitamin are added to an aq. soln. of the materials constituting organisms, dissolved oxygen is removed, and the soln. is transferred into a culture device in a gaseous mixture current. Sludge contg. microbes is inoculated into the soln., and the soln. is held at an appropriate temp. When the soln. is intermittently agitated, cellulose is decomposed, and gaseous methane and gaseous carbon dioxide are liberated. The culture soln. is exchanged, when the liberation of the gases is reduced. The process is repeated to obtain anaerobes having high cellulose decomposing activity. When the cellulose is decomposed by the anaerobes, the gas is liberated at the rate of about 0.5l/l tank volume per day.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a method for culturing anaerobic bacteria used in methane fermentation.

B9 Summary of the Invention The present invention provides a method for culturing anaerobic bacteria by inoculating, for example, swamp bottom mud containing anaerobic bacteria into a culture solution containing constituent substances of living organisms, cellulose, and vitamins. This made it possible to obtain a group of anaerobic bacteria that are highly capable of decomposing cellulose and producing methane.

C2 Prior Art Methane fermentation is known as one of the methods for treating mechanical waste. In this method, a substrate is first decomposed into fatty acids by a group of anaerobic bacteria including a group of methane bacteria, and then this is further decomposed to obtain methane gas. In this case, the fermentation rate varies depending on the type of substrate, and generally the rate-limiting step in methane fermentation is the hydrolysis reaction of the substrate or the reaction to produce methane. When the substrate is an easily decomposable organic substance, the methane production reaction becomes the rate-limiting step, whereas when the substrate is a difficult-to-decompose organic substance, the hydrolysis reaction becomes the rate-limiting step.

D1 Problems to be Solved by the Invention Surplus sludge produced by activated sludge treatment of livestock excrement and wastewater contains a large amount of cellulose. Cellulose found in the natural world includes cellulose that is bound to lignin, which is contained in wood, and cellulose that is not bound to lignin. Lichnocellulose is difficult to decompose and cannot be used as it is for methane fermentation. Hard to become a substrate. The cellulose contained in livestock excrement and surplus sludge is not bound to lignin, so it either becomes a substrate for methane fermentation or has a slow hydrolysis reaction rate. Therefore, in substrates with high cellulose content, the fermentation rate is slow;
The amount of gas generated per meter of white material is small. Particularly at low temperatures, the activity of microorganisms decreases, making it difficult to carry out low-temperature methane fermentation of cellulosic substrates.

An object of the present invention is to obtain a group of anaerobic bacteria that have a high ability to produce methane on cellulosic substrates.

E4 Means for Solving Problems The present invention involves adding cell [1-se] and hitamine to an aqueous solution of constituent substances of living organisms, and expelling dissolved oxygen from the aqueous solution to prepare a culture solution. By culturing a group of anaerobic bacteria using anaerobic bacteria I! 1 is selectively obtained.

F. Example of a culture medium for anaerobic bacteria used in the method of the present invention,
When talking about J-sei, first of all, water and HPO.

Mineral l obtained by dissolving K, I (P O4 so that the degree of a is 6 g/12, and minerals whose components are shown in Tables 1 to 3, respectively. 2. Trace minerals and trace vitamins /
Use α.

Table 2 Table 1 Table and 860xQ of water, 50 each of Mineral I and Mineral 2
1. Add trace mineral 1 OruQ, Fe50. −
Dissolve 71-1.02y, Na1-IC0.5g, and resazurin tmg. Next, cellulose (filter paper powder) 5
g, Yeast Extract 2
g. Add 2 g of Tripticase Pcptomc (from which the protein has been partially degraded with pepsin). After sterilization in an autoclave, cool to room temperature, and
, +CO, (80:20) while bubbling mixed gas, trace vitamin 101. of Table 3. Cystine hydrochloride 0
．． 59/rOmQ, filter sterilize and add Soda Sulfide + 9/2011Q. After confirming that the color of resazurin in the medium has disappeared and there are no molten acid cords, the culture medium is transferred to a suitable culture container under the above-mentioned mixed gas stream. It should be noted that culturing is possible without sterilization except for special purposes.

On the other hand, sludge containing anaerobic bacteria is collected from the bottom of a swamp in a cold region, inoculated into a culture medium in a culture container, kept at an appropriate temperature (15-25℃), and Stir. Cellulose decomposes and methane gas and carbon dioxide gas are generated, but when the gas generation decreases due to a decrease in substrate, replace the culture medium. By repeating the above operations, a group of anaerobic bacteria with high cellulose decomposition activity is selected.

Cellulose (
When methane fermentation was carried out on a batter substrate containing (filter paper powder), 0.5Q per day per tank volume tC.
It was confirmed that gas was generated and therefore the fermentation rate was fast. The composition of the culture medium in this example is shown in Table 4.

Table G0 Effects of the Invention According to the present invention, it is possible to select a culture system that has a high ability to decompose cellulose and produce methane, as seen from the experimental results in Examples. Therefore, if the highly cellulolytic anaerobic bacteria group obtained by Tenryu culture according to the method of the present invention is used as a starter in the methane fermentation process of a substrate containing cellulose, the acclimatization period can be shortened and the processing efficiency of fermentation can be increased. It is possible.

Claims (1)

[Claims] (1) Cellulose and vitamins are added to an aqueous solution of the constituent substances of living organisms, and dissolved oxygen is expelled from the aqueous solution to prepare a culture solution, and this culture solution is used to culture anaerobic bacteria. A method for culturing anaerobic bacteria, which is characterized by selectively obtaining anaerobic bacteria with high decomposition activity.