Rapid fermentation method based on tuna protein sludge

Abstract

The invention discloses a rapid fermentation method based on tuna protein sludge. The rapid fermentation method comprises the following steps: S1, uniformly mixing the tuna protein sludge with a solid carbon source to prepare a substrate; s2, at least one synergist is added, and the synergist comprises a, rhamnolipid fermentation liquor with the concentration of at least 3%, the rhamnolipid fermentation liquor is fermentation liquor which is maturely fermented and is not sterilized, and the rhamnolipid fermentation liquor is added according to the weight ratio of 2-5% of the substrate; b, fish protein enzymatic hydrolysate with the concentration of at least 12%, wherein the fish protein enzymatic hydrolysate is added according to the weight ratio of 3-5% of the substrate; c, combination of neutral protease, cellulase and ligninase, wherein 1-30 thousand units of neutral protease, 2-50 thousand units of cellulase and 2-50 thousand units of ligninase are added into each ton of substrate; s3, inoculating a fermentation strain; and S4, building a heap and fermenting. Compared with conventional fermentation, the fermentation method has the advantages that the synergist is added during inoculation, so that the fermentation period is greatly shortened, the investment of equipment and sites is reduced, and the economic benefit is improved.

Description

Technical Field

[0001] The invention relates to the technical field of tuna sludge treatment, and in particular to a rapid fermentation method based on tuna protein sludge. Background Art

[0002] Tuna is a large, pelagic, edible, economic fish that contains high-quality protein and many nutrients, and is deeply loved by consumers. Therefore, tuna is prepared in large quantities into canned food, fish meal, fish oil and other deep-processed products. However, the deep-processing process of tuna produces a large amount of wastewater, which carries a large amount of tuna residue. After treatment and sedimentation, the wastewater will produce tuna protein sludge. Existing methods for treating tuna protein sludge include: 1. incineration, which will generate a large amount of carbon dioxide emissions and dioxin emissions, which is not conducive to environmental protection; 2. through conventional organic matter generation. The conventional fermentation method for preparing organic fertilizer by fermentation usually includes: first adding a solid carbon source (rice straw powder, straw, rice husk) to the sludge to obtain a substrate, then adding fermentation bacteria (usually containing high-temperature resistant Bacillus, actinomycetes, etc.) to the substrate, and then building a pile for fermentation. The entire fermentation process generally takes about 15-20 days to complete; after 15-20 days, post-fermentation is required. There are also reports that the fermentation speed is increased by adding enzyme preparations such as cellulase and protease during the fermentation process, but overall it still takes about 10-15 days. The fermentation cycle is relatively long and there is room for improvement. Summary of the Invention

[0003] The present invention aims to overcome the above-mentioned defects in the prior art and provides a rapid fermentation method based on tuna protein sludge. By adding at least one synergist, the fermentation cycle of the pile is greatly shortened, and rapid fermentation is achieved. At the same time, it not only reduces the investment in equipment and site, but also the organic fertilizer produced by fermentation can generate economic benefits.

[0004] To achieve the above object, the present invention provides a rapid fermentation method based on tuna protein sludge, comprising the following steps: S1. uniformly mixing tuna protein sludge with a solid carbon source to prepare a substrate; S2. Add at least one synergist, the synergist comprising: a. a rhamnolipid fermentation broth with a concentration of at least 3%, wherein the rhamnolipid fermentation broth is a mature fermentation broth that has not been sterilized, and is added at a weight ratio of 2-5% of the substrate; b. a fish protein hydrolysate having a concentration of at least 12%, added at 3-5% by weight of the substrate; c. A combination of neutral protease, cellulase, and ligninase, wherein 10,000 to 30,000 units of neutral protease, 20,000 to 50,000 units of cellulase, and 20,000 to 50,000 units of ligninase are added per ton of substrate; S3, access to fermentation bacteria; S4. Build a fermentation pile.

[0005] It is further configured that: the solid carbon source is at least one of rice straw powder, straw, and rice husk.

[0006] It is further configured as follows: the tuna wastewater protein sludge and the solid carbon source are mixed in a weight ratio of 1:2-2:1.

[0007] It is further configured that: the fermentation bacteria are EM bacteria and / or Bacillus.

[0008] It is further configured as follows: in S2, the compost is turned and ventilated for 2-5 hours after inoculation.

[0009] It is further set as follows: the width of the pile built in S4 is 1.5-2 meters, and the height is 1-1.5 meters.

[0010] Compared with the prior art, the present invention has the following technical effects: Social benefits: Compared with the original incineration, the resource utilization of land after sludge fermentation reduces a large amount of carbon dioxide emissions and also reduces dioxin emissions during the incineration process, which has significant environmental and social benefits; Economic benefits: Incinerating one ton of sludge costs 300 yuan, while fermented organic fertilizer has a value of 400-800 yuan per ton, making fermentation practical in terms of economic benefits.

[0011] Technical effect: The fermentation cycle is shortened to less than 7 days. Compared with conventional fermentation, the fixed asset investment can be reduced by half, which greatly improves the feasibility of the project. DETAILED DESCRIPTION

[0012] A specific embodiment of the present invention is described in detail below, but it should be understood that the protection scope of the present invention is not limited by the specific embodiment.

[0013] The present invention provides a rapid fermentation method based on tuna protein sludge, comprising the following steps: S1. Preparing a substrate: uniformly mixing the tuna protein sludge with a solid carbon source to obtain a substrate. Preferably, the tuna protein sludge and the solid carbon source are mixed in a weight ratio of 1:2-2:1, wherein the solid carbon source is at least one of rice straw powder, straw, and rice husk.

[0014] S2. Add at least one synergist, the synergist comprising: a. A rhamnolipid fermentation broth having a concentration of at least 3%, wherein the rhamnolipid fermentation broth is a mature, unsterilized fermentation broth and is added at a weight ratio of 2-5% to the substrate, with a preferred concentration of 3-6%. Rhamnolipid, as a biosurfactant, has emulsifying and spreading functions and good biocompatibility. Its use in tuna sludge is primarily targeted at aquatic sludge, which contains a relatively high amount of oil. Its hydrophobicity and the oil film it forms prevent bacteria from contacting and utilizing the substrate, prolonging the adaptation period after the bioreactor is established and affecting the fermentation intensity. The addition of rhamnolipid also prevents the formation of an oil film and emulsifies the fat particles, facilitating the utilization of the bacteria and significantly shortening the adaptation period and fermentation time.

[0015] b. Fish protein hydrolysate with a concentration of at least 12% is added at a weight ratio of 3-5% to the substrate. Fish protein hydrolysate is a high-quality nitrogen source for microbial growth and is conducive to the rapid start-up of fermentation strains.

[0016] c. A combination of neutral protease, cellulase, and ligninase, wherein 10,000-30,000 units of neutral protease, 20,000-50,000 units of cellulase, and 20,000-50,000 units of ligninase are added per ton of substrate. The essence of rapid fermentation is to render the material harmless and degrade organic matter through fermentation heat. Therefore, adding enzyme preparations to the fermentation process is an external enhancement of the fermentation process. In S2, two or more synergists are preferably used in combination, so that they can complement each other and achieve better results; specifically: the combination of rhamnolipid fermentation broth and fish protein enzymatic hydrolysate, the fish protein enzymatic hydrolysate is a high-quality nitrogen source, which is coordinated with the carbon source of the emulsified fat in the rhamnolipid fermentation broth, and has a coordinated enhancement effect on the fermentation, which is exponentially greater than the effect of using them alone, and constitutes the material basis for rapid fermentation; neutral protease, cellulase and ligninase strengthen the external part of the fermentation, and thus cooperate with the rhamnolipid fermentation broth and / or fish protein enzymatic hydrolysate to achieve the joint action of internal and external factors, complement each other, and ensure the realization of the rapid fermentation process.

[0017] S3. Inoculation: First, evenly inoculate the fermentation bacteria into the substrate, then turn the pile over and ventilate for 2-5 hours, which is conducive to bacterial growth. The fermentation bacteria are EM bacteria and / or Bacillus.

[0018] S4. Building a pile for fermentation: The pile body is preferably 1.5-2 meters wide and 1-1.5 meters high, with no limit on length, so that it is easy to turn the pile and ventilate.

[0019] Compared with conventional organic matter fermentation methods, the present invention adds a synergist before inoculation, thereby achieving rapid fermentation, greatly shortening the fermentation cycle, reducing the investment in equipment and site, and improving economy.

[0020] Reactor construction test Pile No. 1: Tuna sludge and straw powder in a 1:1 ratio, 100g of fermentation bacteria, inoculated, and fermented. Samples were taken every 8 hours and the temperature was measured. 2m x 2m, 1m high, 60° slope.

[0021] Pile No. 2: Mix tuna sludge and straw powder in a 1:1 ratio, add 50 kg of 3% rhamnolipid fermentation liquid, and 100 g of fermentation bacteria. After inoculation, build a fermentation pile. Take samples every 8 hours and measure the pile temperature. 2m x 2m, 1m high, 60° slope.

[0022] Pile No. 3: Tuna sludge and straw powder in a 1:1 ratio, 40 kg of fish protein solution (12% protein), and 100 g of fermentation bacteria. After inoculation, a fermentation pile was established. Samples were taken every 8 hours and the pile temperature was measured. 2 m x 2 m, 1 m high, and a 60° slope.

[0023] Pile No. 4: Tuna sludge and straw powder in a 1:1 ratio, 50 kg of 3% rhamnolipid fermentation broth, 40 kg of fish protein solution (12% protein), and 100 g of fermentation bacteria. After inoculation, the pile was established for fermentation. Samples were taken every 8 hours and the temperature was measured. 2 m x 2 m, 1 m high, and a 60° slope.

[0024] Test data

[0025] Comparative Example 1 Compared with pile No. 1, pile No. 2 added 3% rhamnolipid fermentation broth. The heating rate of pile No. 2 was significantly faster than that of pile No. 1, indicating that 3% rhamnolipid fermentation broth (synergist) can effectively enhance the fermentation intensity and reduce the fermentation time.

[0026] Comparative Example 2 Compared with pile No. 1, pile No. 3 added fish protein solution (protein 12%). The heating rate of pile No. 3 was significantly faster than that of pile No. 1, indicating that fish protein solution (protein 12%) can effectively enhance the fermentation intensity and reduce the fermentation time.

[0027] Comparative Example 3 Compared with pile No. 2 or pile No. 3, the heating rate of pile No. 4 is significantly faster than that of pile No. 2 and pile No. 3, which indicates that the fermentation effect of the two synergists in pile No. 4 is significantly better than the fermentation effect of the single synergist in pile No. 2 and pile No. 3.

[0028] The above disclosure is only an embodiment of the present invention, but the present invention is not limited thereto. Any changes that can be conceived by those skilled in the art should fall within the scope of protection of the present invention.

Claims

1. A rapid fermentation method based on tuna protein sludge, characterized in that: The following steps are involved: S1. uniformly mixing tuna protein sludge with a solid carbon source to prepare a substrate; S2. Add at least one synergist, the synergist comprising: a. a rhamnolipid fermentation broth with a concentration of at least 3%, wherein the rhamnolipid fermentation broth is a mature fermentation broth that has not been sterilized, and is added at a weight ratio of 2-5% of the substrate; b. a fish protein hydrolysate having a concentration of at least 12%, added at 3-5% by weight of the substrate; c. A combination of neutral protease, cellulase, and ligninase, wherein 10,000 to 30,000 units of neutral protease, 20,000 to 50,000 units of cellulase, and 20,000 to 50,000 units of ligninase are added per ton of substrate; S3, access to fermentation bacteria; S4. Build a fermentation pile.

2. The rapid fermentation method based on tuna protein sludge according to claim 1, characterized in that: The solid carbon source is at least one of rice straw powder, straw, and rice husk.

3. The rapid fermentation method based on tuna protein sludge according to claim 1, characterized in that: The tuna wastewater protein sludge and the solid carbon source are mixed in a weight ratio of 1:2-2:

1.

4. The rapid fermentation method based on tuna protein sludge according to claim 1, characterized in that: The fermentation bacteria are EM bacteria and / or Bacillus.

5. The rapid fermentation method based on tuna protein sludge according to claim 1, characterized in that: S2 also includes turning the compost and aerating it for 2-5 hours after inoculation.

6. The rapid fermentation method based on tuna protein sludge according to claim 1, characterized in that: The width of the S4 medium-sized pile is 1.5-2 meters and the height is 1-1.5 meters.

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