液态培养条件下烟曲霉去除Cd的研究

Study on Removal of Cd by Aspergillus fumigatus in Liquid Culture

研究了一株高耐Cd的烟曲霉在实验室摇瓶培养条件下对不同浓度Cd的去除效果,测定了其在去除过程中菌株产谷胱甘肽(GSH)的变化.结果表明,在重金属Cd浓度为50mg/L时,烟曲霉去除Cd效率最佳,达到55.5%的去除率,其产生的GSH浓度达到了0.89μmol/mg.研究比较了不同环境条件下烟曲霉对Cd的去除效率,发现在温度30℃,pH5.0,加液量120mL,转速100r/min,接种量0.4mL(1.0×10~7 CFU/mL)的培养条件下,烟曲霉能达到最佳去除Cd的效率.通过这种培养条件的优化,烟曲霉较初始条件下对50mg/L Cd的去除率提高了29.8%,培养体系中GSH浓度增加了0.42μmol/mg.谷胱甘肽过氧化物酶(GPX)和谷胱甘肽还原酶(GR)的变化表明烟曲霉在优化的液态生长环境下可以较好去除培养体系中的重金属Cd,其产生的GSH对Cd的去除有促进作用,其解毒机制可能是依靠体内GPX和GR将应激产生的氧化性物质去除来实现.

The removal efficiency of a Cd-resistant Aspergillus furnigatus under different concentrations of Cd in laboratory flask culture was studied, and the changes of glutathione （GSH） produc- tion in the strain were determined. The results showed that the removal rate of Cd was 55.5% when the concentration of Cd was 50 mg/L,and the concentration of GSH was 0.89 9tool/rag. The comparison of Cd removal efficiency by Aspergillus fumigatus under different conditions showed that the optimal condition was 30 ℃ ,pH value of 5.0,add fluid volume of 120 mL,speed of 100 r/min,and inoculation amount of 0.4 mL （1.0 × 10^7 CFU/mL）. Under the optimal condition, the removal rate of Cd was 29.8 % higher than that under the initial condition,and the GSH content in the culture system was increased by 0.42 μmol/mg. The changes of glutathione peroxidase （GPX） and glutathione reductase （GR） indicated that Aspergillus fu- rnigatus could remove the heavy metal Cd in the culture system under the optimized liquid growth condi- tions,GSH could promote the removal of cadmium,and its detoxification mechanism could be achieved by removing the oxidative substances produced by stress by GPX and GR in vivo.