JPH10120482A - Composting acceleration method and composting acceleration agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain high-quality compost within a period similar to the conventional process even by using sawdust, wood chips, etc., having high lignin content and low decomposition speed as the raw material by mixing xylanase to the raw material in a compost production process. SOLUTION: Animal excrete and food waste constituting compost raw materials are mixed with sawdust, wood chips, etc., as a water-content controlling agent to control the water content of the raw materials. The obtained raw material is mixed with xylanase and the mixture is maintained at 20-60 deg.C for >=1 day and subjected to conventional, compost-production process to produce compost. Preferably the xylanase has a lignin decomposition promoting action, an optimum temperature of 50-100 deg.C and a thermal stability to leave about >=90% of activity after the treatment at 50 deg.C for 30min and about >=50% of activity after the treatment at 60 deg.C for 30min. The process is suitably applicable to a compost raw material containing >=5wt.% of lignin and >=10wt.% of sawdust or wood chips. The raw material may be mixed with agriculture, forestry and fishery wastes such as rice straw and wheat straw, industrial waste such as corrugated board and newspaper and returned compost.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compost made from animal excrement / garbage, wood chips, sawdust and the like, and a method for producing the same. In particular, the present invention relates to a method for maturing a high-quality compost similar to the conventional one in a short period of time even when a raw material containing a large amount of fibrous hardly decomposable substances is used. The present invention is agriculture, forestry and fisheries waste, industrial waste,
This technology can be widely applied to general household waste.

[0002]

2. Description of the Related Art Animal excrement and garbage contain a large number of fertilizer components having high agricultural value and can be said to be excellent organic fertilizer materials. However, when used as is, it is not suitable for application due to disadvantages such as environmental pollution and crop damage. Therefore, a technology for processing into compost is required.

As a conventional technique for producing compost, animal excrement / garbage and a moisture regulator are mixed, deposited and fermented, and cut back at appropriate times to promote more uniform fermentation and mature the compost. Among them, control of the initial moisture content adjustment, maintenance of an appropriate fermentation temperature, and maintenance of air permeability by stacking / turning are essential conditions for producing high-quality compost.

[0004] The water content can be determined by separating and pre-drying manure of animal excrement, woody materials such as sawdust and wood as a water regulator, paper materials such as corrugated cardboard, newsprint and pulp, agricultural waste such as rice straw and wheat straw, and return compost. It is prepared by mixing an appropriate amount of solid materials such as ceramics and styrofoam with animal waste and garbage, but sawdust is often used, particularly from the viewpoint of water adsorption capacity and cost. However, the disadvantage of this sawdust is that it contains a large amount of lignin that is difficult to decompose and decompose as compost, and the residual lignin significantly reduces the value of compost.

[0005] Deposition can accumulate fermentation heat by maintaining an appropriate height, but from the viewpoint of maintaining air permeability, the lower the better, the better.
Generally, it is about 50 cm to 3 m. The cutback is performed for the purpose of supplying the enzyme to the inside of the pile and homogenizing the compost, and the fermentation period can be shortened by performing the cutout appropriately so as not to inhibit the fermentation. In the conventional stacking method and the like, it takes time and effort to switch back. Therefore, recently, compost houses equipped with a stirrer are increasing.

[0006] In recent years, methods of treating various types of waste have been studied, and attention has been paid particularly to the development of techniques for reducing the burden on the environment. The compost production technology is an environmentally friendly technology that uses agriculture, forestry and fisheries waste or industrial waste, which has often been discarded as a raw material, and converts the waste into a useful material called compost to be recycled into the natural world.

[0007] However, livestock production is increasing in scale due to low-cost production, and its excreta is also concentrated and generated in large quantities, increasing the environmental load. In addition, the burden required for garbage disposal in cities is increasing. Since the necessity of increasing the use amount of hardly decomposable materials such as wood chips as a moisture regulator has been increasing, development of a more efficient treatment method has been demanded with respect to the conventional compost production technology.

As a technique for this, a high-speed fermentation method using a stirrer and the addition of various fungicides that further promote the decomposition of proteins and fibers in compost materials has been proposed.

Further, in the conventional production of compost, in order to reduce the water content of the livestock manure as a water regulator to the livestock manure accumulation, sawdust is mixed to reduce the water content of the livestock manure accumulation and left for a certain period of time. Was naturally fermented and composted. A very characteristic feature of this composting of manure aggregates is the use of a water conditioner with an extremely high lignin content called sawdust, which is very difficult to decompose by natural fermentation. There was a problem that the quality of compost deteriorated due to undecomposed lignin.

A conventional composting method is disclosed in Japanese Patent Laid-Open No. 5-163.
090, as described in 090, after mixing fibrinolytic enzymes in the presence of water with the agglomerate of fibrous solid organic waste, and allowing the fibrous solid organic waste to act to a degree that does not liquefy but reduces its rigidity. A method of aerobic fermentation by keeping the temperature under the supply of enzymes and mixing them was devised. However, in the case of ordinary fibrolytic enzymes, the fermentation temperature in compost is a high temperature environment of 80 degrees and the enzyme is inactivated due to the high reaction temperature. Lignin could not be reduced from the compost, and only low-quality compost could be produced during the normal fermentation period, and natural fermentation was required for a long period of time to produce high-quality compost.

[0011]

In order to compost a large amount of animal waste or garbage, a large amount of a water regulator is also required. In many cases, sawdust and chopped wood chips are used, but recently large-sized ones have been mainly distributed, and conventional compost manufacturing methods have not been able to completely disassemble them and maintain their shape. In many cases, the compost aggregates are hard to disintegrate when left as they are or when compost is hardly broken down. When the compost produced in this manner is sprayed on farmland, the remaining sawdust and fine wood chips are separated, and the lignin content in the compost does not decrease due to insufficient maturation, which may affect the crop. Particularly, this problem is a serious problem when the lignin content of the raw material for composting is 5% or more, and the content of sawdust or wood chips is 10% or more.

The present invention provides a technique for producing a high-quality compost in the same period as before even when sawdust, wood chips and the like having a low lignin content and a low decomposition rate are used as raw materials. is there.

[0013]

Means for Solving the Problems The present inventors have conducted intensive studies to improve the above-mentioned drawbacks of the prior art, and as a result, mixed xylanase with the compost material and changed the fermentation conditions from those of the conventional method. In recent years, sawdust with a high lignin content
The present inventors have found that high-quality compost can be produced even when wood chips are used as a moisture regulator, and have further found that the use of the xylanase as a heat-resistant enzyme enhances the rate of lignin decomposition in compost, thereby completing the present invention. Hereinafter, the present invention will be described in detail.

First, animal excrement and raw garbage, which are compost raw materials, and sawdust and wood chips as a moisture regulator are mixed and adjusted to a moisture content suitable for compost fermentation. At this time, other agricultural, forestry and fishery wastes such as rice straw and wheat straw, cardboard, newspaper, pulp,
An appropriate amount of industrial waste such as ceramic or styrene foam or back compost may be mixed. Next, xylanase is added here and mixed.

The xylanase used in the present invention is not sufficiently effective for cellulase, which is a normal fibrinolytic enzyme, or hemicellulase that degrades hemicellulose, and xylanase is effectively used. In particular, among the xylanases, those having a neutral and high apicerase activity, particularly those having a high activity of decomposing arapinoxylan to efficiently separate lignin from cellulose fibers, and mixtures thereof can be used more effectively.

Examples of the xylanase that can be used in the present invention include an xylanase having an optimum temperature in the range of 50 ° C. to 100 ° C., and a thermostability of about 9 ° C. for 30 minutes at 50 ° C.
A xylanase that retains 0% or more of the enzymatic activity and exhibits a residual activity of about 50% or more even after treatment at 60 ° C. for 30 minutes is even more preferable.
The optimal pH range of the reaction according to 1 is pH 5 to 8, the stable pH range is 3 to 9, and the xylan 1.4-β-D-
Cultures of Bacillus sp. Bacillus sp. 2113 or 208 and its variants, hydrolyzing xylosidic bonds to produce reducing sugars of xylo-oligosaccharides, mutants thereof, and improved strains by genetic engineering techniques Thermostable xylanase obtained from cocoa. Bacillus 720/1 described in JP-A-8-92284
Strain (LMG P-14798), Bacillus p
umilus PRL B12 and Bacillus
lichenformis or a derivative or mutant of the strain thereof, having a pH in the range of about 5 to 10 and about 50 to 50.
A xylanase which is active over a temperature range of 80 ° C. 90 ° C. described in JP-A-6-261750
Up to about 65-70 ° C. SD902 (133
No. 56), a xylanase derived from a bacterium selected from its subspecies, its mutants, and improved strains by genetic engineering techniques. Thermomyces l described in JP-A-7-87970
Xylanase from annuquinosus DSM5826 and its mutants. B described in JP-A-7-67637
xylanase derived from P. acillus pumilus PRL B12 and mutants and variants thereof, purified xylanase consisting essentially of the amino acid sequence of amino acids 1 to 200 (SEQ ID NO: 24), and xylanase produced by a transformed strain of P. licheniformis . Xylanase produced from Bacillus bacteria described in JP-A-7-150493. JP-A-5-209
Bacillus licheniformis described in 385 is SD516
There are xylanases derived from bacteria selected from the subspecies, the mutants, and the improved strains by genetic engineering techniques.

Specific names of commercially available xylanase that can be used in the present invention include, for example, "Naturase NT-250" manufactured by Rakutohokusei Co., Ltd. and "Biofeed Plus" manufactured by Novo Nordicx. it can.
However, it is not particularly limited as long as it has the same xylanase activity.

The xylanase of the present invention can be used in combination with conventional enzymes having different effects such as cellulase, hemicellulase, protease and lipase for the purpose of reducing lignin in compost and promoting composting.

As the enzyme which can be used in the present invention, a material having good high-temperature stability is more suitable because the temperature in the compost is a high temperature environment of about 70 degrees Celsius.
Xylanases that retain about 90% or more of the enzymatic activity in the treatment at 0 ° C. for 30 minutes and show the residual activity of about 50% or more even in the treatment at 60 ° C. for 30 minutes can provide a better composting promoting effect.

The xylanase drug substance used in the method and agent for promoting composting of the present invention can be used in any form of powder, granule, and liquid. It is better to mix homogeneously. For this purpose, it is preferable to prepare an enzyme solution in an amount of 1 / 10,000, more preferably 1/1000 weight or more based on the compost material, and to sprinkle and mix it gradually. Alternatively, when a compost stirrer is added in an appropriate amount from the top during stirring, it is easy to mix uniformly. The concentration of the xylanase drug substance used at this time is not particularly limited, but a substance having a titer of 1000 or more per kg of the xylanase drug substance is desirable when a quick effect is expected.
The xylanase drug substance used in the method and agent for promoting composting of the present invention is a commonly used calcium carbonate,
It can be diluted with a bulking agent such as flour or the like, and can be coated with oils and fats.

The compost raw material mixed with xylanase is maintained at 20 to 70 ° C., more preferably 40 to 60 ° C., for at least 1 day, more preferably 4 days. For this purpose, the temperature rise can be easily suppressed by leaving the apparatus to stand as it is or setting the height of the stack to 1 m or less, more preferably 60 cm or less. Further, stirring may be performed several times a day with a stirrer in order to improve the mixing of the enzyme. In any case, the enzyme is distributed over the whole, 70 ° C. or more, preferably 60 ° C.
It is important that the temperature does not rise above ° C.

Next, the compost raw material thus treated can be subjected to a usual compost production process. Although turning back may be appropriately performed by a bulking method, compost fermentation can be promoted by using a stirring method using a stirrer. When the lignin content of the compost material used at this time is 5% or more and the content of sawdust or wood chips is 10% or more, higher effects of the present invention can be expected.

The fermenter can be of any type such as open type, closed type, linear type, circular type and circular type. In this case, the height of the pile is 1 m or less, preferably 60 cm or less,
If the mixture is stirred for up to 7 days and then returned to the normal pile height and the compost fermentation is advanced, a higher quality compost can be produced in a short period of time.

In general, composting of a compost raw material proceeds by the action of microorganisms mixed in the raw material or externally added materials and microbial agents for promoting fermentation, and is two months to one year in the case of the sedimentation method, and even in the case of the stirring method. It takes a long period of one to six months. However, in the case where sawdust is used as a raw material, even if fermented for a long period of time, the decomposition is insufficient and many of them remain close to the original form. In addition, the aggregate structure of the compost tends to be large, which is not suitable for spraying agricultural land.

As described above, in the compost obtained by adding xylanase to the compost fermentation, sawdust and wood chips are decomposed more finely and the original form is not maintained, and the lignin content in the compost raw material is reduced by at least 7% after at least 7 days. Due to this, the aggregate structure is subdivided into a shape that is easily broken down, which is also preferable for spraying agricultural land.

[0026]

Embodiments of the present invention will be described below.

Example 1 A mixture of 60% chicken dung and 40% cow dung was mixed with sawdust until the water content became about 65% to prepare about 0.5 m ³ of compost material. 100 g of "Biofeed Plus" manufactured by Novo Nordicx Co., Ltd. was crushed in a mortar, and a liquid suspended in 1 liter of water was sprinkled from the top using a jar to make the mixture as uniform as possible, and the compost materials were mixed again. This was piled up to about 60 cm, and left as it was for 3 days while blowing air from the lower part with a blower. At this time, the compost temperature was between 20 and 60 ° C. for the first day. In this compost, sawdust is apt to collapse, and the lignin content is adjusted to P.O. J. As a result of quantification according to the method of Van Soest et al., It was reduced from 12.5% to 9.0%.

Example 2 The compost of Example 1 was about 60 cm
And allowed to stand for 7 days while blowing air with a blower. The temperature of the compost was between 20 and 70 ° C. Sawdust did not remain in shape, but was subdivided. As a result of quantifying the lignin content in the same manner as in Example 1, the lignin content was reduced to 7.0%.

Comparative Example 1 A mixture of 60% chicken dung and 40% cow dung was mixed with sawdust to prepare 0.5 m ² of a compost material having a water content of about 65%. Stack this to about 60cm,
It was left as it was for 3 days while blowing air from the lower part with a blower. At this time, the compost temperature was between 20 and 60 ° C. for the first day. In this compost, the sawdust kept its initial shape, and the lignin content was quantified in the same manner as in Example 1, and as a result, it did not change from 12.5%.

[Comparative Example 2] The compost of Comparative Example 1 was about 60 cm
And allowed to stand for 7 days while blowing air with a blower. The temperature of the compost was between 20 and 70 ° C. The sawdust stayed in shape and only slightly collapsed. As a result of quantifying the lignin content in the same manner as in Example 1, it was 12.2%.

[Comparative Example 3] Sawdust was mixed with a mixture of chicken dung 60% and cow dung 40% until the water content became about 65% to prepare a compost material 3.0 m ³ . This was piled up to about 1.5 m, and left as it was for 3 days while blowing air from the lower part with a blower. At this time, the compost temperature rose to 72 ° C. on the first day, and further rose to 87 ° C. on the second day. In this compost, the sawdust was close to the initial shape, and the lignin content was quantified in the same manner as in Example 1. As a result, the lignin content did not change from 12.3%.

Example 3 Sawdust was mixed with a mixture of chicken dung 60% and cow dung 40% until the water content became about 65% to prepare 0.5 m ³ of compost material. Also, 50 g of "Biofeed Plus" manufactured by Novo Nordics Co., Ltd. and 50 g of "Naturase NT-250" manufactured by Rakutohokusei Co., Ltd. were ground and mixed in a mortar, and a liquid obtained by suspending this in 1 liter of water was used as a compost material with a jar. The top was sprinkled as evenly as possible, and the compost materials were mixed again. This was piled up to about 60 cm, and left as it was for 3 days while blowing air from the lower part with a blower. At this time, the compost temperature was 2 for the first day.
It was between 0-60 ° C. In this compost, sawdust was easily disintegrated, and the lignin content was determined in the same manner as in Example 1. As a result, it was 10.2%.

Example 4 The compost of Example 3 was about 60 cm
And allowed to stand for 7 days while blowing air with a blower. The temperature of the compost was between 20 and 70 ° C. Sawdust did not remain in shape, but was subdivided. As a result of quantifying the lignin content in the same manner as in Example 1, the lignin content was reduced to 8.5%.

Example 5 Sawdust was mixed with a mixture of chicken dung 60% and cow dung 40% until the water content became about 65% to prepare about 10 m ³ of compost material. In addition, 250 g of "Biofeed Plus" manufactured by Novo Nordics Co., Ltd. and 250 g of "Naturase NT-250" manufactured by Rakutohokusei Co., Ltd. were pulverized and mixed with a mixer to prepare a liquid in which 10 g of water was suspended. Compost raw materials in a composting room with a self-propelled drum type stirrer
酵素 60 cm, and the enzyme suspension was sprinkled and mixed little by little from above while operating the stirrer. It was left as it was for 3 days while blowing air from the lower part with a blower. At this time, the compost temperature is 20-60 ° C for the first day.
Was between. In this compost, sawdust was easily broken down. As a result of quantifying the lignin content in the same manner as in Example 1,
It decreased from 1.1% to 8.9%.

Example 6 The compost of Example 5 was stirred once a day with a stirrer and allowed to stand for 10 days. During this period, air was blown in from the lower part. The temperature of the compost was between 20 and 70 ° C. Sawdust did not remain in shape, but was subdivided. As a result of quantifying the lignin content in the same manner as in Example 1, 3.5%
Was decreasing.

[Example 7] The promotion of composting produced by a blending ratio of 80% by weight of a purified xylanase mixture derived from a microorganism culture described below, which was produced by a known method, 19% by weight of a cellulase enzyme, and the remaining cellulose-degrading bacteria The agent was mixed and dispersed in calcium carbonate, diluted, and sprinkled evenly on the compost material. Bacillus sp. 2113 Bacillus sp. 208 Bacillus 720/1 strain (LMG P-1479)
8) Bacillus pumilus PRL B12 Bacillus licheniformis Bacillus sp. SD902 Thermomyces lanuquinosusDS
M5826 Bacillus pumilus PRL B12 Bacillus licheniformis SD5
16

Example 8 A mixture of 60% chicken dung and 40% cow dung was mixed with sawdust to a water content of about 65% to prepare about 10 m ³ of compost material. Further, 500 g of the xylanase-containing composting accelerator produced in Example 7 was mixed with a mixer to prepare a liquid suspended in 10 l of water. Compost material is put in a composting room with a self-propelled drum type stirrer in a height of 50-6.
It was piled up to 0 cm, and the enzyme suspension was sprinkled and mixed little by little from the top while operating the stirrer. It was left as it was for 3 days while blowing air from the lower part with a blower. At this time, the compost temperature was between 20 and 60 ° C. for the first day. In this compost, sawdust was easily broken down. As a result of quantifying the lignin content in the same manner as in Example 1,
It decreased from 1.0% to 8.1%.

Example 9 The compost of Example 8 was stirred once a day with a stirrer and allowed to stand for 10 days. During this period, air was blown in from the lower part. The temperature of the compost was between 23-75 ° C. Sawdust did not remain in shape, but was subdivided. As a result of quantifying the lignin content in the same manner as in Example 1, 2.9%
Was decreasing.

[0039]

According to the present invention, sawdust and wood chips which could not be completely decomposed by the conventional compost production method are fragmented, the compost aggregate structure is fragmented, and the lignin content is reduced. It is possible to produce a compost which is preferable for spraying agricultural land. This increases the utilization rate of sawdust and wood chips as a compost material, which leads to effective use of resources, and also has the effect of shortening the compost preparation period as compared with the conventional method.

Claims (11)

[Claims] 1. A method for promoting composting comprising adding xylanase in a compost production step. 2. The method for accelerating compost according to claim 1, wherein the xylanase is a xylanase having a lignin decomposition accelerating activity in a compost production step. 3. The optimum temperature of xylanase is from 50 ° C. to 1
3. The method for accelerating compost according to claim 1 or 2, wherein the xylanase is a high-temperature-active xylanase within a temperature range of 00C. 4. The thermostability of xylanase is 50 ° C., 30
Xylanase activity of more than 90%
The method according to any one of claims 1 to 3, wherein the xylanase exhibits a residual activity of about 50% or more even after treatment at 60 ° C for 30 minutes. 5. A method for promoting composting, comprising adding the xylanase according to any one of claims 1 to 4 and an enzyme mixture containing an enzyme other than the xylanase in the compost production step. 6. The method according to claim 1, wherein the temperature is maintained at 20 to 60 ° C. for at least one day after the addition of xylanase. 7. The method for promoting composting according to claim 1, wherein the compost raw material before the treatment is a compost containing lignin in an amount of 5% or more. 8. The method for promoting composting according to claim 1, wherein composting is promoted by using a stirrer in the production of compost. 9. The method according to claim 1, wherein the compost material contains at least 10% by weight or more of sawdust or wood chips. 10. The method for accelerating compost production according to claim 1, wherein the compost has a lignin content reduced by 2% by weight or more compared to the raw material for compost. 11. A composting promoter comprising 1 to 80% by weight of a xylanase enzyme, 1 to 19% by weight of a cellulase enzyme, and the balance being cellulolytic bacteria.