蛋白核小球藻生物膜对镉胁迫的生理响应及去除效果分析

为研究镉胁迫下蛋白核小球藻生物膜的生理响应及其去除效果，实验设计了不同的镉初始浓度梯度，分析镉胁迫下蛋白核小球藻生物膜的叶绿素a、硝酸还原酶、胞外多聚糖（EPS）等生理特征指标，并比较了蛋白核小球藻生物膜在不同的镉初始浓度下对镉的去除效果。结果表明:镉会抑制蛋白核小球藻生物膜的生长及其硝酸还原酶的产生，并且抑制程度随着镉初始浓度的增大而增加，20 mg/L的镉还会导致部分藻类生物膜的死亡；另外，镉会抑制蛋白核小球藻生物膜EPS的产生，但随着接触时间的增加，镉会刺激藻类生物膜分泌少量EPS来阻止镉离子进入藻细胞；镉初始浓度为15 mg/L时，蛋白核小球藻生物膜对镉的去除效果最好，达到89.83%。以上成果可为藻类生物膜去除重金属镉的后续研究奠定基础。

PHYSIOLOGICAL RESPONSE OF CHLORELLA PYRENOIDOSA BIOFILM TO CADMIUM STRESS AND ITS REMOVAL EFFECT

In order to study the physiological response of Chlorella pyrenoidosa biofilm and removal efficiency on cadmium(Cd), the physiological activity indexes, such as chlorophyll a, nitrate reductase and extracellular polysaccharide (EPS), were analyzed in different initial concentrations of wastewater containing Cd. Additionally, the removal efficiencies of Cd by Chlorella pyrenoidosa biofilm in different concentrations of Cd were compared. Result showed that:the growth of Chlorella pyrenoidosa biofilm and its amount of nitrate reductase were inhibited by Cd, and the degree of inhibition became stronger in higher concentration of Cd; when the concentration of Cd reached 20 mg/L, it would lead to the death of some algae biofilms; Cd would inhibite the production of EPS in Chlorella pyrenoidosa biofilm, but with the increase of contact time, Cd stimulated the biofilm to secrete a small amount of EPS to prevent metal ions from entering algal cells. The Chlorella pyrenoidosa biofilm had a good effect on removal of Cd. When the concentration of Cd was 15 mg/L, Chlorella pyrenoidosa biofilm had the highest removal efficiency on Cd, which could reach 89.83%.