A strain of Lactobacillus paracasei and a method for preparing black soldier fly larvae protein peptides thereof

Abstract

The invention discloses a breeding process for improving the protein peptide content and antibacterial property of black soldier fly larvae based on Lactobacillus paracasei, and belongs to the field of biotechnology. The Lactobacillus paracasei disclosed in the invention has a strain number of JAAS-11, which has been preserved in Guangdong Province Microbial Culture Collection Center on July 18, 2023, with a preservation number of GDMCC NO:63661. The Lactobacillus paracasei JAAS-11 provided by the present invention, after fermentation and culture, is fermented to the breeding materials, i.e., kitchen waste, of black soldier fly larvae. Under the same conditions of other breeding processes, relative to materials not subjected to fermentation, the crude protein content and protein peptide (molecular weight <10K Da) content of black soldier fly larvae are increased by 6.4% and 13.2% respectively, the antioxidant activity is increased by 16.0%, the antibacterial ability is increased by 29.6%, and the weight of the black soldier fly larvae obtained by breeding is also increased by 16.5%. The strain of the invention is easy to culture and has strong adaptability, and can establish a low-cost and simple breeding method for improving the protein peptide content and antibacterial performance of black soldier fly larvae.

Description

Technical Field

[0001] The invention belongs to the technical field of biological preparations, and specifically relates to a microbial strain and its application in black soldier fly breeding. Background Art

[0002] Black soldier fly (Hermetia illucens) is an insect of the genus Hermetia of the family Schizontidae in the order Diptera. It can convert organic solid wastes such as kitchen waste, livestock and poultry feces, and abandoned crops into larvae rich in protein and fat. Black soldier flies have the characteristics of wide-ranging diet, short reproduction cycle, and large biomass. They are an effective way to convert organic waste into protein. Chinese patent CN117106618A reports a composite functional microbial agent that cooperates with black soldier flies to treat kitchen waste and fruit and vegetable waste; the agent is composed of Serratia nematophila, Stenotrophomonas maltophilia, etc., which can be beneficial to the growth of black soldier flies and improve the conversion rate of kitchen waste / fruit and vegetable waste. Chinese patent CN111172075A uses strains isolated from the intestines of black soldier flies as a composite microbial preparation composed of Enterococcus faecalis, Proteus mirabilis, and Citrobacter freundii, so that black soldier flies can better convert biomass such as bean dregs, with a conversion rate of up to 17.33%.

[0003] Black soldier fly larvae are rich in crude protein (40% to 45%), crude fat (35% to 40%) and chitin, and are widely used in animal husbandry and fishery production to partially replace soybean meal or fish meal protein. Crude protein contains active ingredients such as protein peptides, antimicrobial peptides, antioxidants and immunomodulators; based on this, the content of protein peptides in black soldier fly larvae and their antibacterial properties are increased, making them a promising alternative to antibiotics. Summary of the invention

[0004] Purpose of the invention: The technical problem to be solved by the present invention is to address the deficiencies in the prior art and to propose a method for preparing black soldier fly larvae protein peptides based on Lactobacillus paracasei, thereby increasing the content of black soldier fly larvae protein peptides and their antibacterial properties.

[0005] To achieve the above object, the present invention provides a Lactobacillus paracasei, which can improve the content of black soldier fly larvae protein peptides and their antibacterial properties by treating kitchen materials with Lactobacillus paracasei.

[0006] A strain of Lactobacillus paracasei, whose classification name is Lactobacillus paracasei, the strain number is JAAS-11, the preservation number is GDMCC NO: 63661, the preservation time is July 18, 2023, and the preservation address is the Institute of Microbiology, Guangdong Academy of Sciences, 5th Floor, Building 59, No. 100 Xianlie Middle Road, Guangzhou.

[0007] The method for screening and identifying Lactobacillus paracasei comprises the following steps: homogenizing and diluting the obtained black soldier fly larvae and applying the mixture to MRS-CaCO 3 Solid plates were incubated at 30°C for 24-48 hours, and single colonies that produced hydrolysis circles were selected and repeatedly plated on MRS-CaCO 3 The pure cultured microorganism strains were finally obtained on the solid plate. The pure cultured strains obtained by screening were sequenced by 16S and compared with the NCBI database for homology, and the phylogenetic tree was constructed using MGEA10 for analysis. 3 The solid plate formula is: peptone 10g / L, beef extract powder 5.0g / L, yeast extract powder 4.0g / L, glucose 20.0g / L, dipotassium hydrogen phosphate 2.0g / L, triammonium citrate 2.0g / L, sodium acetate 5.0g / L, magnesium sulfate 0.2g / L, manganese sulfate 0.05g / L, agar 15.0g / L, Tween-80 1.0g / L, calcium carbonate 15.0g / L. The pH value is 6.2±0.2.

[0008] The second aspect of the present invention is to provide a method for preparing black soldier fly larvae protein peptides using the above-mentioned Lactobacillus paracasei, the method comprising the following steps:

[0009] (1) inoculating a bacterial liquid of Lactobacillus paracasei JAAS-11 into food waste for fermentation to obtain a Lactobacillus paracasei JAAS-11 treated material;

[0010] (2) Using the Lactobacillus paracasei JAAS-11 treated material to feed black soldier fly larvae, obtaining a sample of the fifth instar larvae of the black soldier fly, pulping, and dialysis to obtain black soldier fly larvae protein peptides.

[0011] Wherein, the black soldier fly larvae protein peptide has a molecular weight of less than 10 kDa, preferably in the range of 1 to 10 kDa.

[0012] Wherein, in step (1), the bacterial solution of Lactobacillus paracasei JAAS-11 is prepared by the following method: a single colony of Lactobacillus paracasei JAAS-11 is selected and inoculated into MRS liquid culture medium, and cultured at 28-40° C. until the growth of the strain is stable. Preferably, the bacterial solution is cultured until OD 600 Preferably, the stirring speed is 100-200 rpm. More preferably, the mixture is cultured at 30°C and 200 rpm until the OD 600 is 5.

[0013] The single colony of Lactobacillus paracasei JAAS-11 is obtained by strain activation, wherein the frozen Lactobacillus paracasei JAAS-11 is streaked on an MRS solid plate and cultured at 28-40° C. for 24-48 hours, preferably at 30° C. for 48 hours.

[0014] The MRS solid plate formula is: peptone 10g / L, beef extract powder 5.0g / L, yeast extract powder 4.0g / L, glucose 20.0g / L, dipotassium hydrogen phosphate 2.0g / L, triammonium citrate 2.0g / L, sodium acetate 5.0g / L, magnesium sulfate 0.2g / L, manganese sulfate 0.05g / L, agar 15.0g / L, Tween-80 1.0g / L. pH value 6.2±0.2.

[0015] The formula of MRS liquid culture medium is: peptone 10g / L, beef extract powder 5.0g / L, yeast extract powder 4.0g / L, glucose 20.0g / L, dipotassium hydrogen phosphate 2.0g / L, triammonium citrate 2.0g / L, sodium acetate 5.0g / L, magnesium sulfate 0.2g / L, manganese sulfate 0.05g / L, Tween-80 1.0g / L. pH value 6.2±0.2.

[0016] Wherein, in step (1), the inoculation amount of the Lactobacillus paracasei JAAS-11 bacterial solution is calculated as 4-5 mL of the Lactobacillus paracasei JAAS-11 bacterial solution per 100 g of food waste. Preferably, 5 mL of the Lactobacillus paracasei JAAS-11 bacterial solution is inoculated per 100 g of food waste.

[0017] Wherein, in step (1), the fermentation temperature is 28-40°C and the fermentation time is 24-48 hours. Preferably, the fermentation temperature is 30°C and the relative humidity is 70% for 48 hours.

[0018] Wherein, in step (1), the moisture content of the kitchen waste is 70±1% (m / m).

[0019] Wherein, in step (2), the black soldier fly larvae are 1st to 3rd instar black soldier fly larvae; the black soldier fly larvae are added in an amount of 100 to 120 black soldier fly larvae per 100g of Lactobacillus paracasei JAAS-11 treated material. Preferably, the black soldier fly larvae are 3rd instar black soldier fly larvae; the black soldier fly larvae are added in an amount of 100 black soldier fly larvae per 100g of Lactobacillus paracasei JAAS-11 treated material.

[0020] Preferably, in step (2), the Lactobacillus paracasei JAAS-11 treated material is put into a breeding box to raise black soldier fly larvae, wherein each cm 3 0.2-0.5 g of treated material is added to the culture box. Preferably, 3 Add 0.2-0.3g of treated material.

[0021] Wherein, in step (2), the temperature of the breeding is 28-38°C, the relative humidity is 70%-75%, and the time is 8-10 days. Preferably, the temperature is 37°C, the relative humidity is 72%, and the time is 9 days, and the black soldier fly larvae are raised until they change color from white to brown, thereby obtaining the fifth instar black soldier fly larvae.

[0022] Preferably, in step (2), the slurrying is performed by homogenizing the fifth instar larvae of black soldier flies by a homogenizer. The dialysis is performed by using a dialysis bag with a molecular weight cutoff of 10 kDa, and the black soldier fly larvae protein peptide is obtained by freeze-drying after dialysis.

[0023] Wherein, the method can improve the content, antioxidant and antibacterial properties of black soldier fly larvae protein peptides. Preferably, the black soldier fly larvae protein peptides can be used to prepare antioxidant and / or antibacterial products. Wherein, the antibacterial is the inhibition of, including but not limited to, Staphylococcus aureus. The antioxidant and / or antibacterial products include but are not limited to feed products.

[0024] Among them, the method can also improve the conversion rate of food waste.

[0025] Beneficial effect: The present invention provides an application of a strain of Lactobacillus paracasei and its synergistic black soldier fly in treating food waste and preparing black soldier fly larvae protein peptides. The present invention screens and obtains a strain of Lactobacillus paracasei JAAS-11, treats food waste with it to obtain Lactobacillus paracasei JAAS-11 treated material, and black soldier flies are added to the treated material for breeding. Compared with untreated food waste, the black soldier flies obtained by feeding the Lactobacillus paracasei JAAS-11 treated material have crude protein content and protein peptide (molecular weight <10kDa) content increased by 6.4% and 13.2% respectively, and its antioxidant activity increased by 16.0%, antibacterial ability increased by 29.6%, and the weight of the black soldier flies obtained by breeding also increased by 16.5%. In addition, the conversion rate of food waste is also increased to 49.21%. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments, and the above and / or other advantages of the present invention will become more clear.

[0027] Figure 1 is the phylogenetic tree of Lactobacillus paracasei. Lactobacillus sp. Seq-Conting1 is the 16S sequence described in Example 1.

[0028] Figure 2 The diameter of the inhibition zone of the black soldier fly protein peptide obtained from the untreated group in Example 2 was measured.

[0029] Figure 3The diameter of the inhibition zone of the black soldier fly protein peptide obtained by the Lactobacillus paracasei JAAS-11 treatment group in Example 3 was determined. DETAILED DESCRIPTION

[0030] In order to make the above-mentioned purpose, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with specific examples. The examples will help to understand the present invention, but the protection scope of the present invention is not limited to the following examples.

[0031] In the following embodiments, the Lactobacillus paracasei JAAS-11 is classified and named as Lactobacillus paracasei (Lacticaseibacillus paracasei), with a deposit number of GDMCC NO: 63661, a deposit date of July 18, 2023, and a deposit address of the Institute of Microbiology, Guangdong Academy of Sciences, 5th Floor, Building 59, No. 100, Xianlie Middle Road, Guangzhou.

[0032] In the following examples, the MRS-CaCO 3 The solid plate formula is: peptone 10g / L, beef extract powder 5.0g / L, yeast extract powder 4.0g / L, glucose 20.0g / L, dipotassium hydrogen phosphate 2.0g / L, triammonium citrate 2.0g / L, sodium acetate 5.0g / L, magnesium sulfate 0.2g / L, manganese sulfate 0.05g / L, agar 15.0g / L, Tween-80 1.0g / L, calcium carbonate 15.0g / L. The pH value is 6.2±0.2.

[0033] The MRS liquid culture medium is formulated as follows: peptone 10 g / L, beef extract powder 5.0 g / L, yeast extract powder 4.0 g / L, glucose 20.0 g / L, dipotassium hydrogen phosphate 2.0 g / L, triammonium citrate 2.0 g / L, sodium acetate 5.0 g / L, magnesium sulfate 0.2 g / L, manganese sulfate 0.05 g / L, Tween-80 1.0 g / L. pH value 6.2±0.2.

[0034] The MRS solid culture medium is formulated as follows: peptone 10 g / L, beef extract powder 5.0 g / L, yeast extract powder 4.0 g / L, glucose 20.0 g / L, dipotassium hydrogen phosphate 2.0 g / L, triammonium citrate 2.0 g / L, sodium acetate 5.0 g / L, magnesium sulfate 0.2 g / L, manganese sulfate 0.05 g / L, agar 15.0 g / L, Tween-80 1.0 g / L. pH value 6.2±0.2.

[0035] Embodiment 1: screening and identification of Lactobacillus paracasei

[0036] 1. Isolation and purification of bacterial strains

[0037] (1) Weigh 200.0 g of fresh black soldier fly larvae fed with food waste and homogenize them. Weigh 200.0 g of the homogenized black soldier fly larvae slurry, add 80.0 mL of deionized water, shake at 30.0°C and 200 rpm for 1 hour, and take out and let it stand for 30 minutes.

[0038] (2) Take the supernatant and dilute it with sterile water to 1.0×10 -5 The diluted bacterial suspension was evenly spread on the MRS-CaCO 3 Solid plate. Incubate at 30℃ for 48h, select single colonies that produce hydrolysis circles from the plate, and repeatedly spread them on MRS-CaCO 3 Finally, pure culture of microbial strains is obtained on the solid plate.

[0039] 2. Identification of strains

[0040] The selected bacteria were subjected to 16S sequencing. The DNA of the bacterial genome was extracted using a column DNA method (column DNA extraction kit was purchased from Sangon Biotech (Shanghai) Co., Ltd.), and the extracted DNA was subjected to PCR amplification using 16S amplification primers 27F and 1492R. The 27F sequence was SEQ No: 1: 5'-AGAGTTTGATCCTGGCTCAG-3', and the 1429R sequence was SEQ No: 2: 5'-GGTTACCTTGTTACGACTT-3'. The PCR amplification system is shown in Table 1, and the PCR amplification program is shown in Table 2.

[0041] Table 1 PCR amplification system

[0042]

[0043] Table 2 PCR amplification program

[0044]

[0045] Note: The three processes of cyclic denaturation-annealing-extension are repeated for a total of 30 cycles.

[0046] The PCR amplification product was sent to General Biotech (Anhui) Co., Ltd. for sequencing. The 16S fragment Seq1 (gene sequence shown in SEQ No: 3) obtained after sequencing was compared with the NCBI database for homology, and a phylogenetic tree was constructed using MGEA10; see for details. Figure 1 .from Figure 1 It can be seen that the strain was identified as Lactobacillus paracasei.

[0047] The above-mentioned isolated and purified Lactobacillus paracasei strain is Lactobacillus paracasei (Lacticaseibacillus paracasei), the strain number is JAAS-11, the preservation address is: Institute of Microbiology, Guangdong Academy of Sciences, 5th Floor, Building 59, No. 100 Xianlie Middle Road, Guangzhou, the preservation number is: GDMCC NO: 63661, and the preservation date is: July 18, 2023.

[0048] The 16S fragment gene sequence SEQ No: 3

[0049]

[0050] Example 2: Untreated kitchen waste and black soldier fly breeding process

[0051] 300 g of kitchen waste with a moisture content of 70% (m / m) was put into a breeding box (17 cm×11 cm×7 cm) at one time. 300 3rd-instar black soldier fly larvae were added to the breeding box and placed in a constant temperature and humidity incubator (temperature: 37°C, humidity: 72.00%) for breeding. The growth and feeding of the larvae were observed daily. After 9 days of breeding, the breeding was terminated when the experimental larvae changed color (from white to brown), and the 5th-instar larvae samples of the untreated group were obtained, and the relevant data were recorded.

[0052] Example 3: Processing of materials with Lactobacillus paracasei JAAS-11 and breeding of black soldier flies

[0053] 1. Preparation of materials treated with Lactobacillus paracasei JAAS-11

[0054] (1) Activation of Lactobacillus paracasei JAAS-11

[0055] Take out the frozen Lactobacillus paracasei JAAS-11 from the -80℃ refrigerator and streak it on the MRS solid plate, and incubate it in a constant temperature incubator at 30℃ for 48h; pick a single colony and inoculate it into MRS liquid culture medium, and incubate it at 30℃ and 200rpm to the stable period, that is, OD 600 =5, and obtain the bacterial liquid of Lactobacillus paracasei JAAS-11.

[0056] (2) Solid fermentation of food waste by Lactobacillus paracasei JAAS-11

[0057] 300 g of kitchen waste material with a moisture content of 70% (m / m) was put into a culture box (17 cm×11 cm×7 cm) at one time, 15 mL of the Lactobacillus paracasei JAAS-11 bacterial solution obtained by the inoculation step (1) was cultured, and the mixture was fermented in an incubator at a constant temperature and humidity of 30° C. (relative humidity 70%) for 48 h to obtain a Lactobacillus paracasei JAAS-11 treated material, which was stored at room temperature for standby use. The composition difference between the Lactobacillus paracasei JAAS-11 treated material and the kitchen waste untreated material is shown in Table 3. As can be seen from Table 3, after the kitchen waste was treated with Lactobacillus paracasei JAAS-11, the crude protein content was significantly increased, and the cellulose and ash contents were decreased.

[0058] Table 3 List of ingredients of materials treated with Lactobacillus paracasei JAAS-11 and untreated food waste

[0059]

[0060] 2. Black soldier fly breeding technology

[0061] With reference to Example 2, the kitchen waste material was replaced with the material treated with Lactobacillus paracasei JAAS-11 to obtain a sample of the fifth instar larvae of black soldier flies in the Lactobacillus paracasei JAAS-11 treated group.

[0062] Example 4: Crude protein content, total antioxidant activity and antibacterial activity of the black soldier fly larvae obtained from the fifth instar larvae of the black soldier fly in the untreated kitchen waste group

[0063] 1. Determination of protein content

[0064] Take the untreated group of black soldier flies fifth instar larvae sample prepared in Example 2, dry the black soldier flies at 55°C, grind and sieve, accurately weigh 0.1000g of the dried sample (accurate to 0.0001g), add 1 piece of high-efficiency Kjeldahl nitrogen determination catalyst and 10mL of concentrated sulfuric acid, and shake well. Place the digestion tube on the digestion furnace and heat and boil at 420°C for 20min. When the digestion liquid and the sample are digested and transparent, the digestion is completed and cooled. While digesting the sample, make three blank measurements. Except for not adding the sample, other operations are the same as when measuring the sample.

[0065] Before distillation, prepare a 400g / L sodium hydroxide and boric acid indicator mixture (20g dissolved in 2L, then add 14mL of methyl red and 10mL of bromocresol green and mix well), fully preheat the nitrogen analyzer, clean the pipeline with a blank tube, and replace the digestion tube to measure the test solution after the reading is stable. The results showed that the crude protein content of the black soldier fly in the fifth-instar larvae of the untreated kitchen waste group was 454.464mg / g.

[0066] 2. Determination of total antioxidant activity

[0067] Dialysis Bag Dialysis Black Soldier Fly Larvae Protein Peptide

[0068] (1) Dialysis bag pretreatment: Cut the 10 kDa dialysis bag into 11 cm long pieces and wash away surface impurities by boiling with EDTA (pH = 8.0) before use. After taking out the dialysis bag, wash it thoroughly with distilled water to ensure that no detergent or impurities remain on the surface of the dialysis bag.

[0069] (2) Dialysis and determination of protein peptide content: Take out the fifth-instar larval sample of the untreated group of black soldier flies prepared in Example 2, and use a homogenizer to homogenize it. Put the homogenized sample into a dialysis bag, and clamp both ends with dialysis clips or cable ties. Put the dialysis bag containing the sample into a beaker, add 50 mL of distilled water, ensure that the dialysis bag is completely immersed in distilled water, and dialyze for 36 hours, changing the distilled water every 12 hours. After the dialysis is completed, mix the dialysate three times, determine the protein peptide content therein by the BCA method, and freeze-dry it in a freeze dryer. The results showed that the content of black soldier fly larvae protein peptide (<10kDa) in the fifth-instar larval sample of the untreated group of black soldier flies was 113.472 mg / g.

[0070] The black soldier fly larvae protein peptide (<10kDa) lyophilized powder was taken out and prepared into a series of solutions with a concentration of 10mg / mL with ultrapure water. The total antioxidant capacity test was carried out according to the instructions of the total antioxidant capacity test kit (purchased from Nanjing Jiancheng Bioengineering Institute). The results showed that the total antioxidant capacity of the black soldier fly larvae protein peptide in the fifth instar black soldier fly larvae sample of the untreated group was 25.372U / mg.

[0071] 3. Determination of antibacterial activity

[0072] (1) Extraction of antimicrobial peptides from black soldier fly larvae

[0073] Prepare antimicrobial peptide extract (10% acetic acid, 0.01 mol / L Na 2 EDTA). The untreated group of black soldier fly larvae samples of the fifth instar described in Example 2 were mixed evenly with the antimicrobial peptide extract (v:v=1:10), extracted at 200 rpm and 37°C for half an hour, and transferred to a centrifuge (3500 rpm, 25 min) to collect the supernatant as the crude antimicrobial peptide extract. The supernatant was further freeze-dried to obtain the black soldier fly larvae antimicrobial peptide.

[0074] (2) Cultivation of Staphylococcus aureus (CICC 10306)

[0075] The Staphylococcus aureus (CICC 10306) strain frozen at -80°C was inoculated onto LB solid culture medium and placed in a constant temperature incubator at 37°C for 24 hours; a single colony was picked and inoculated into LB liquid culture medium, and cultured at 37°C and 200 rpm for 24 hours to obtain a Staphylococcus aureus bacterial liquid.

[0076] (3) Determination of antibacterial activity of antimicrobial peptides from black soldier fly larvae

[0077] The negative control was sterile water; the antibiotic chloramphenicol was used as the positive control, and the concentration of chloramphenicol aqueous solution was prepared to be 0.5 mg / mL. The concentration of Staphylococcus aureus was determined to be 1.0×10 9CFU / mL, take an appropriate amount of Staphylococcus aureus liquid and evenly spread it on the LB medium. Gently place an Oxford cup with a diameter of 7.5mm on the LB plate, add an equal amount of black soldier fly larvae antimicrobial peptide to the Oxford cup, culture it in a constant temperature incubator at 37℃ for 10h, and observe and measure the diameter of the inhibition zone. Figure 2 As shown, the diameter of the inhibition zone is 27±0.2 mm.

[0078] Example 5: Crude protein content, total antioxidant activity and antibacterial activity of the fifth-instar larvae of black soldier flies obtained from the Lactobacillus paracasei JAAS-11-treated group

[0079] Referring to the method in Example 4, the crude protein content, protein peptide content, total antioxidant activity and antibacterial activity of the fifth instar larvae of black soldier flies in the Lactobacillus paracasei JAAS-11 treated group obtained in Example 3 were measured. The results showed that the protein content of the black soldier flies larvae obtained from the fifth instar larvae of black soldier flies in the Lactobacillus paracasei JAAS-11 treated group was 483.687 mg / g, the protein peptide (<10 kDa) content was 128.500 mg / g, the total antioxidant activity was 29.431 U / mg, and the diameter of the inhibition zone was 35 ± 0.1 mm. Figure 3 shown.

[0080] It can be seen from the results of Comparative Example 4 and Example 5 that, compared with the fifth instar larvae sample of the untreated group, the fifth instar larvae of the black soldier fly obtained by treating with Lactobacillus paracasei JAAS-11 had a crude protein content and protein peptide (molecular weight <10 kDa) content increased by 6.4% and 13.2%, respectively, and its antioxidant activity increased by 16.0%, and its antibacterial ability increased by 29.6%.

[0081] Example 6: Effect of Lactobacillus paracasei and black soldier flies in treating kitchen waste

[0082] Single worm weight: After the black soldier fly breeding described in Examples 2 and 3 is completed, the fifth-instar black soldier fly larvae obtained therefrom are weighed respectively, and the kitchen waste feed conversion rate is calculated.

[0083] The feed conversion rate calculation method is as follows: after the breeding is completed, the black soldier fly larvae and insect sand are separated, the insect sand on the surface of the larvae are cleaned, the weight of the larvae and the weight of the insect sand are recorded, and the kitchen waste, insect sand, and black soldier fly larvae of the untreated and treated groups are transferred to a 55° C. oven and dried to constant weight, and the dry weight of the samples is recorded.

[0084]

[0085] c: feed conversion rate (%); m 1 : Black soldier fly larvae weight gain dry weight; m 2 : Total dry weight of added feed; m 3: Total dry weight of insect sand

[0086] The results showed that the weight of the black soldier fly larvae obtained by Example 2 was 158.31 mg, and the feed conversion rate of the breeding process described in Example 2 was 44.33%. The weight of the black soldier fly larvae obtained by Example 3 was 184.42 mg, and the feed conversion rate of the breeding process described in Example 3 was 49.21%.

Claims

1. A strain of Lactobacillus paracasei, characterized in that The strain is called Lactobacillus paracasei ( Lacticaseibacillus paracasei )JAAS-11, the deposit number is GDMCC NO: 63661, and the deposit date is July 18, 2023.

2. A method for preparing black soldier fly larvae protein peptides using Lactobacillus paracasei according to claim 1, characterized in that: The steps include: (1) inoculating a bacterial liquid of Lactobacillus paracasei JAAS-11 into food waste for fermentation to obtain a Lactobacillus paracasei JAAS-11 treated material; (2) Using the Lactobacillus paracasei JAAS-11 treated material to feed black soldier fly larvae, obtaining a sample of the fifth instar larvae of the black soldier fly, pulping, and dialyzing to obtain black soldier fly larvae protein peptides.

3. The method according to claim 2, characterized in that The molecular weight of the black soldier fly larvae protein peptide is less than 10 kDa.

4. The method according to claim 3, characterized in that The black soldier fly larvae protein peptide has a molecular weight of 1-10 kDa.

5. The method according to claim 2, characterized in that In step (1), the bacterial solution of Lactobacillus paracasei JAAS-11 is prepared according to the following method: a single colony of Lactobacillus paracasei JAAS-11 is picked up and placed in MRS liquid culture medium, and cultured at 28-40° C. until the strain reaches a stable growth phase.

6. The method according to claim 2, characterized in that In step (1), the inoculation amount of the Lactobacillus paracasei JAAS-11 bacterial solution is calculated by inoculating 4 to 5 mL of the Lactobacillus paracasei JAAS-11 bacterial solution into every 100 g of food waste.

7. The method according to claim 2, characterized in that In step (1), the fermentation temperature is 28-40°C and the fermentation time is 24-48 hours.

8. The method according to claim 2, characterized in that: In step (2), the black soldier fly larvae are 1st to 3rd instar larvae of black soldier flies; the amount of black soldier fly larvae added is calculated as 100 to 120 black soldier fly larvae per 100 g of the material treated with Lactobacillus paracasei JAAS-11.

9. The method according to claim 2, characterized in that: In step (2), the raising temperature is 28-38°C, the relative humidity is 70%-75%, and the time is 8-10 days.

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