海洋地衣芽孢杆菌的絮凝活性研究及机理探讨

摘要

Using marine Bacillus licheniformis DHS-40 as a flocculant-producing strain,we determined the active components of microbial flocculant by a qualitative experiment,evaluated flocculation stability by a sixcombined agitator for program-controlled coagulation test and a gravity sedimentation method,characterized microscopic morphologies of microbial flocculant and flocculant particles by scanning electron microscope and atomic force microscope,and discussed flocculation mechanism.Results indicated that the active components of microbial flocculant of marine Bacillus licheniformis were mixture of polysaccharides and proteins.The flocculation activity was above 80％ when microbial flocculant dosage was 0.05 g · L-1,environmental pH value was 4.0～8.0,and environmental temperature was 0～50 ℃.Environmental pH value hardly affect the flocculation activity,however,the flocculation activity decreased rapidly under the alkaline environment(pH＞8.0),and lost all when pH value was 10.0.The morphology of microbial flocculant possessed a chain structure with different depths and channels.The morphology of flocculant particles presented a stacked structure.Depended on charge adsorption and bridging action,microbial flocculant was settled together with the turbidity of water,thus a chieved the goal of purifying water body.%以海洋地衣芽孢杆菌DHS-40为絮凝剂产生菌,通过定性测试鉴定所产微生物絮凝剂的絮凝活性有效成分,采用程控混凝实验六联搅拌仪和重力沉降法评价其絮凝稳定性,通过扫描电子显微镜和原子力显微镜表征微生物絮凝剂和絮凝颗粒的微观形貌,并初步探讨了微生物絮凝剂的絮凝机理.结果表明,海洋地衣芽孢杆菌DHS-40所产微生物絮凝剂的絮凝活性有效成分为多糖和蛋白质的混合物;当微生物絮凝剂投加量为0.05 9·L-1、环境pH值为4.0～8.0、环境温度为0～50℃时,絮凝活性达80％以上;絮凝活性基本不受环境pH值的影响,但在碱性较强(pH＞8.0)时絮凝活性迅速下降,在pH值为10.0时完全丧失;微生物絮凝剂呈链状结构,且有深浅不等的沟回;絮凝颗粒呈层叠结构.微生物絮凝剂依靠电荷吸附和桥联作用带动水中的浑浊物共同沉降,从而达到净化水体的目的.