酵母细胞表达金属硫蛋白对铅离子的吸附研究

Enhanced Pb^(2+) Biosorption By Recombinant Saccharomyces cerevisiae Expressing Human Metallothionein

根据人肝金属硫蛋白的基因序列,结合酿酒酵母菌密码子使用规律,改造并合成了可在酵母细胞内高效表达的金属硫蛋白基因,并将该基因转入酵母细胞内进行了表达。以野生型菌株为对照,初步测定了酿酒酵母INVSC1-mt菌株对Pb2+的吸附作用。研究结果表明,金属硫蛋白基因的表达有助于提高酿酒酵母细胞对Pb2+的吸附作用,其最大吸附量比野生型菌株提高了11%。同时,酿酒酵母INVSC1-mt菌株吸附Pb2+的速度较快,在30 min时,其吸附率就达到了96.03%,吸附量为5.76 mg/g湿重细胞。而野生型菌株至120 min时,其吸附率才达到90.44%。

The recombinant Saccharomyces cerevisiae expressing human hepatic metallothionein is constructed for biosorption of lead （II）. The gene sequence of mt is modified for codon preference of S. cerevisiae and synthe- sized using chemical method. The maximal biosorption capability of lead compounds Pb2＋ of the recombinant in- creases more than 11% compared with the control. For mr-expressing recombinant strains, a rapid adsorption oc- curres within the first 30 rain with a significant level of Pb^2＋ （5.76mg/g [ humid weight ] ）, the biosorption rea- ches about 96% of the saturated value within 30 rain. For comparison, S..cerevisiae cells reach its maximal Pb2＋ adsorption capacity （5.43 mg/g） until 120 min. The recombinant will be useful in enhancement the effectiveness of lead biosorption in practice.