China Animal Husbandry and Veterinary Medicine ›› 2021, Vol. 48 ›› Issue (12): 4607-4617.doi: 10.16431/j.cnki.1671-7236.2021.12.029

• Preventive Veterinary Medicine • Previous Articles     Next Articles

Optimization of Microcapsule Preparation Technology of Recombinant Lactococcus lactis Expressing Bovine Lactoferrin Peptide

ZHANG Junyan1, TAN Hongchao1, CHEN Peipei2, WANG Xiaona1,3, JIANG Yanping1,3, CUI Wen1,3, QIAO Xinyuan1,3, WANG Li1,3, ZHOU Han1,3, XU Yigang1,3, LI Yijing1,3, TANG Lijie1,3   

  1. 1. College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, China;
    2. Animal Husbandry and Veterinary Station, Sucheng District, Suqian City, Jiangsu Province, Suqian 223800, China;
    3. Key Laboratory of Animal Disease Pathogen Biology, Northeast Scientific Observation and Experiment Station, Ministry of Agriculture and Rural Affairs, Harbin 150030, China
  • Revised:2021-05-19 Online:2021-12-20 Published:2021-12-02

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Abstract: In order to facilitate the storage and transportation of recombinant Lactococcus lactis after fermentation, microcapsules were prepared by recombinant Lactococcus lactis pAMJ399-LFBA/MG1363, which could express lactoferrin peptide.The preparation conditions of microcapsules were optimized, and the related biological characteristics of the encapsulated recombinant bacteria were detected.In order to select the best wall material and its concentration, the embedding amount was measured by controlling the single variable experiment of different wall materials and wall material concentrations.The release rate of microcapsules was compared through simulated gastric and intestinal fluid environment experiment, and the shelf life experiment of different wall materials was carried out to compare the lowest viable bacteria number.The response surface experiment was used to determine the optimal process conditions, and the microcapsules were prepared under the optimal process conditions for verification.The optimized results were as follows:Sodium alginate and chitosan were finally selected as wall materials.Under the conditions of sodium alginate was 2.49%, chitosan was 0.96%, CaCl2 was 6.67% and solidification time was 57 min, the microcapsule effect was the best, and the prediction embedding amount was 7.85×108 CFU/g.Microcapsules existed stably in simulated gastric juice, and could completely break in simulated intestinal juice, and could release more than 95% of lactic acid bacteria in microcapsules.After the sodium alginate-chitosan microcapsules were stored at 4 ℃ for 3 weeks, the number of viable bacteria in microcapsules was 1.41×107 CFU/g.The results showed that the embedding amount of microcapsules was 8.08×108 CFU/g.After being stored at room temperature for 2 weeks, the viable bacteria count could still reach 3.89×106 CFU/g.The lactoferrin peptide expressed by recombinant Lactococcus lactis in microcapsules was detected by ELISA, and the antibacterial assay showed that the lactoferrin peptide expressed by recombinant Lactobacillus lactis in microcapsules still had significant inhibitory effect on Salmonella and Staphylococcus aureus.These results indicated that the recombinant Lactococcus lactis expressing lactoferrin peptide could be prepared into microcapsules with low cost, long shelf life and gastric juice resistance, which laid a foundation for the further application of recombinant lactic acid bacteria in production.

Key words: recombinant Lactococcus lactis; lactoferrin peptide; microcapsules; optimization of process

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