【摘要】 微藻聚集行为在藻华的治理等方面具有重要作用,也是目前微藻生物燃料收集的瓶颈之一.以小球衣藻为研究对象,观察污泥胞外聚合物(Extracellular polymeric substance,EPS)对微藻聚集行为的影响,并通过其聚集数据采集、EPS客观特性和微藻的自身响应等方面探究其可能的聚集原因.结果显示:随着外源性污泥EPS浓度的增大,小球衣藻聚集率从18.4%上升到81.8%,并且在110 mg/L时达到聚集率最大值.微藻细胞运动速度从26.8μm/s上升到49.4μm/s,增大了细胞间的碰撞几率,促进了微藻的聚集.三维荧光光谱表明,污泥胞外聚合物刺激了微藻色氨酸类蛋白和芳香族类蛋白的分泌,其分泌量与EPS的浓度成正比.但是外源性EPS溶液Zeta电位变化与微藻的聚集率呈负相关关系,并非微藻聚集原因.本研究表明外源性污泥胞外聚合物能够促进微藻的聚集,结果可为下一步在分子方面的探究提供实验基础.(图7表3参38)更多还原

【Abstract】 Though extracellular polymeric substances(EPSs) play important roles in the aggregation of activated microbial sludge, little is known about their effects on the aggregation of other, non-bacterial species. In this study, the interaction between activated sludge-extracted EPSs and microalgal cells(Chlamydomonas microsphaera) was investigated. Image and video analyses were applied to track microalgal aggregation and motility. The characteristics of the EPSs used and the selfresponses of the tested microalgae were also measured. Results showed that with the application of increasing amounts of exogenous EPSs, the aggregation rate of Chlamydomonas microsphaera increased from 18.4 to 81.8%, with the maximum aggregation rate reached with the application of 110 mg/L of EPSs. In the presence of activated sludge-extracted EPSs,microalgal cells moved faster, with their speed increasing from 26.8 to 49.4 μm/s, which caused there to be higher probabilities of collision among microalgal cells that favored microalgal aggregation. The results of EEM also showed that the EPS content of the activated sludge was proportional to that of the aromatic and tryptophan proteins secreted by the microalgae, which implied that the sludge-extracted EPSs stimulated the secretion of aromatic and tryptophan proteins by the microalgae.However, the zeta potential of the exogenous EPS solution was negatively correlated with the aggregation rate of the microalgae, indicating that zeta potential changes were not responsible for the accumulation of microalgal cells. In conclusion,it was found that sludge-extracted EPSs enhanced the aggregation of microalgae.更多还原