Abstract:In order to achieve the homologous expression of asparaginase gene asp in Aspergillus niger CICC2462,the asparaginase engineering strains were construced. The specific primers were designed according to asparaginase gene asp sequence in the NCBI(GI:145231287)to amplify the coding region of asp and pSZHG-asp expression vector was constructed. Then agrobacterium mediated method was utilized to transform Aspergillus niger,and homologous recombinations which glucoamylase gene(glaA) was replaced by Asp were screened. The expression products of the transformant were analyzed using SDS-PAGE and enzyme activity detection. Eight homologous recombination strains,where glaA locus was replaced,were obtained,and the supernatant in 4 of them were measured. The result of SDS-PAGE showed protein bands at 42 000,the amount of the recombinated protein was 185~417 μg/mL,and the highest enzyme activity of fermentation broth was up to 21 111 U/mL.
