Chimeric lysozyme variant and application thereof in animal feed additive
A chimeric lysozyme variant has an improved heat resistance and is encoded by a polynucleotide. A novel chimeric lysozyme sequence is constructed, and high-efficiency expression in a host cell is achieved. The thermal stability of the chimeric lysozyme under the condition of 60° C. is nearly doubled compared to a parental sequence. The chimeric lysozyme variant can be used to prepare product that is antibiotic, for example, animal feed additive containing the chimeric lysozyme variant and an animal feed containing the animal feed additive.
1 . A chimeric lysozyme variant, wherein the chimeric lysozyme variant has an amino acid sequence set forth in SEQ ID NO: 8, or has at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity to SEQ ID NO: 8; and wherein the chimeric lysozyme variant has a lysozyme activity and exhibits increased thermostability as compared to a lysozyme of SEQ ID NO: 4 or SEQ ID NO: 6.
2 . The chimeric lysozyme variant of claim 1 , wherein the chimeric lysozyme variant has an amino acid sequence set forth in SEQ ID NO: 8.
3 . A method of substituting an antibiotic in an animal, comprising administering to the animal an effective amount of the chimeric lysozyme variant of claim 1 .
4 . A polynucleotide, wherein the polynucleotide encodes the chimeric lysozyme variant of claim 1 .
5 . The polynucleotide of claim 4 , wherein the polynucleotide has a nucleotide sequence set forth in SEQ ID NO: 7.
6 . A recombinant vector, wherein the recombinant vector contains the polynucleotide of claim 4 .
7 . A host cell, wherein the host cell contains the recombinant vector of claim 6 .
8 . The host cell of claim 7 , wherein the host cell is selected from any of the Aspergillus niger, Pichia pastoris, Aspergillus oryzae, Trichoderma reesei, Bacillus subtilis, Bacillus licheniformis or Escherichia coli.
9 . An animal feed additive, wherein the animal feed additive comprises the chimeric lysozyme variant of claim 1 .
10 . The animal feed additive of claim 9 , wherein the chimeric lysozyme variant is added in an amount of 100-1000 g chimeric lysozyme variant per ton of animal feed.
11 . The animal feed additive of claim 10 , wherein the chimeric lysozyme variant is added in an amount of 250-500 g chimeric lysozyme variant per ton of animal feed.
12 . A method for improving one or more performance parameters of an animal, comprising administering to the animal a feed or feed additive comprising the chimeric lysozyme variant of claim 1 , wherein the performance parameters comprise weight gain or feed conversion rate of the animal.