高产果糖基转移酶米曲霉菌株的选育

Breeding of Aspergillus Oryzae Strain for Producing Fructosyltransferase

为了获得果糖基转移酶活力较高的米曲霉菌株,应用基因组改组技术对其进行选育。以米曲霉菌株SBB201(Aspergillus oryzae SBB201)为出发菌,利用米曲霉分生孢子紫外线-氯化锂复合诱变建立候选文库,并以此作为原生质体融合的出发菌株制备原生质体并进行PEG介导的融合。通过3轮基因组改组,筛选得到一株果糖基转移酶活力达到178.90U/g的菌株,相对原始菌株的酶活105.09U/g提高了70.24%,并经传代培养测定,融合突变株具有较好的遗传稳定性。

In order to obtain Aspergillus oryzae strains that with a high of fructosyltransferase activity,Aspergi//us oryzae SBB201 as the original strain was used to breed with genome shuffling technique. A candidate library had been built-up through the uv-lithium chloride compound mutation at conidia of Aspergillus oryzae. Mutant strains were chosen from the library as the initial strains for protoplast preparation and fusion mediated by PEG. After three rounds of genome recombination,a fusion mutant was obtained with its enzyme activity reached to 178.90U/g. Compared with the ones of original strain （105.09U/g）,the enzyme activity of the fusion mutant had increased by 70.24%. From the assay results of fructosyltransferase activity in different generation,it was found that the fusion mutant RIII-7 showed a good of genetic stability.