Bacillus subtilis Bac01 was mutated by 15 keV N+ ions of 1.5×1016 cm-2. The mutant strain Bac11 with high yield of endoglucanase was isolated using carboxymethylcellulose sodium and congo red indicative plates. I...Bacillus subtilis Bac01 was mutated by 15 keV N+ ions of 1.5×1016 cm-2. The mutant strain Bac11 with high yield of endoglucanase was isolated using carboxymethylcellulose sodium and congo red indicative plates. It exhibited higher endoglucanase activitiy (381.89IU) than the original strain Bac01 (93.33IU). Two 1,500 bp endoglucanase gene fragments were obtained with PCR amplification from B. subtilis Bac01 and mutant strain Bac11. BLAST comparison result indicated that 10 nucleotides mutated. Bioinformatics methods were used to analyze the two predicted amino acid sequences, and it was found that 5 amino acid residues changed, being all in the cellulose-binding domain of endoglucanase.展开更多
文摘从可食用的纳豆中筛选出一株能够高效降解黄曲霉毒素B1(aflatoxin B1,简称AFB1)的细菌,该细菌的发酵上清液经浓缩后制成的粗酶液对AFB1降解率达到91.4%。对该菌进行了分类地位鉴定并初步研究了粗酶液的酶学性质。结果表明,该菌经生理生化和16S r DNA序列比对鉴定为枯草芽孢杆菌,并命名为Natto3。Natto3的粗酶液降解AFB1的最适培养时间为72h,最适反应温度为37℃,最适p H值是8.5,Zn2+、Mn2+、Mg2+、Cu2+、Li+五种金属离子均会不同程度地抑制降解活性。此外,将该粗酶液添加在被黄曲霉毒素高度污染的花生样品中进行脱毒实验,可使花生中AFB1的浓度从192μg/kg降至43μg/kg。
基金Supported by the Natural Science Foundations of Xinjiang (No.2009211B06) Xinjiang University (No. QN070109)
文摘Bacillus subtilis Bac01 was mutated by 15 keV N+ ions of 1.5×1016 cm-2. The mutant strain Bac11 with high yield of endoglucanase was isolated using carboxymethylcellulose sodium and congo red indicative plates. It exhibited higher endoglucanase activitiy (381.89IU) than the original strain Bac01 (93.33IU). Two 1,500 bp endoglucanase gene fragments were obtained with PCR amplification from B. subtilis Bac01 and mutant strain Bac11. BLAST comparison result indicated that 10 nucleotides mutated. Bioinformatics methods were used to analyze the two predicted amino acid sequences, and it was found that 5 amino acid residues changed, being all in the cellulose-binding domain of endoglucanase.
