两种改性方法对聚乙烯填料表面生物膜特性的影响

研究了聚乙烯生物填料的表面经化学氧化--铁离子覆盖和化学氧化--表面接枝明胶2种方法改性后，其生物膜组成、微生物种属等的变化。结果表明，2种改性方法均能有效增加填料表面生物膜胞外聚合物含量:胞外多糖含量分别增加了63%和18.5%，使生物膜的黏附性能增强；胞外蛋白质含量分别增加了43%和15.4%，导致生物膜活性增强。显微镜检表明，改性填料挂膜过程中后生动物出现时间提前，这有利于废水处理效果更稳定。聚合酶链式反应--变性梯度凝胶电泳（PCR--DGGE）图谱分析显示:2种改性填料与未改性填料生物种群的相似性较高，分别达98.0%和93.8%；但改性填料的优势菌属增多，微生物浓度增大。 

Effluence of two methods of surface modification on the biofilm characteristics attached on the polyethylene carrier

Two kinds of surface modification methods, chemical oxidation--surface covered with iron ion and chemical oxidation--surface grafting of gelatin, were used to improve the surface properties of polyethylene bio-carrier, and the composition and microbial species in biofilm formed on the modified bio-carrier surface were investigated. The experimental results showed that two kinds of modification methods could effectively increase the content of biofilm extracellular polymeric substances. The extracellular polysaccharide contents were increased by 63% and 18.5%, respectively, which benefited the biofilm adhesion and formation. The extracellular protein contents were increased by 43% and 15.4%, which indicated that biofilm activity was greatly increased. Microscopy observation showed that the appearance of metazoan in the modified biofilm was earlier than in the unmodified biofilm, which could be indicative for high efficiency and stable performance. Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analysis showed that the composition of microbial species on the biofilm had little significant difference before and after modification, with the similarity of microbial species of 98.0% and 93.8%, respectively, but the quantity of dominant genus and microbial concentration were greatly increased.