This study explored the effect of extracellular polymeric substance (EPS) production on the performance of membrane-based biofilm reactors. Changing EPS production was induced by eliminating one of the main EPS polysaccharides, i.e., Pel. The studies were carried out using a pure culture of either Pseudomonas aeruginosa or an isogenic P. aeruginosa mutant that was unable to produce the Pel polysaccharide. The biofilm cell density for both strains was compared to confirm the Pel deletion mutant decreased overall EPS production in a bioreactor system. When the Pel-deficient mutant was grown as a biofilm, its cell density, i.e., ratio of cells/(cells + EPS), was 74 % higher than the wild type, showing EPS production was reduced by eliminating pel production. The growth kinetics were determined for both strains. The Pel-deficient mutant had a maximum specific growth rate ($\widehat{\mu }$) that was 14% higher than the wild type. Next, the effects of EPS reduction on reactor performance were assessed for a membrane aerated biofilm reactor (MABR) and a membrane bioreactor (MBR). For the MABR, the organic removal with the Pel-deficient mutant was around 8% higher than for the wild type. For the MBR, the time to reach the fouling threshold was 65 % greater for the Pel-deficient mutant than for the wild type. These results suggest that amount of EPS production can have significant effects on bacterial growth kinetics and bacterial cell density, which in turn can affect the performance of the membrane-based biofilm reactors. In both cases, lower EPS production correlated with more efficient treatment processes.

本研究探讨了胞外聚合物 (EPS) 的产生对基于膜的生物膜反应器性能的影响。改变 EPS 生产是通过消除一种主要的 EPS 多糖，即 Pel 来诱导的。这些研究是使用铜绿假单胞菌或同基因铜绿假单胞菌的纯培养物进行的不能产生 Pel 多糖的突变体。比较两种菌株的生物膜细胞密度，以确认 Pel 缺失突变体降低了生物反应器系统中的整体 EPS 产量。当 Pel 缺陷型突变体作为生物膜生长时，其细胞密度，即细胞/（细胞 + EPS）的比率，比野生型高 74%，表明通过消除 pel 生产减少了 EPS 生产。确定了两种菌株的生长动力学。Pel 缺陷突变体具有最大比生长率（$\widehat{\mu }$) 比野生型高 14%。接下来，评估了 EPS 减少对膜曝气生物膜反应器 (MABR) 和膜生物反应器 (MBR) 的反应器性能的影响。对于 MABR，Pel 缺陷突变体的有机物去除率比野生型高约 8%。对于 MBR，Pel 缺陷突变体达到污垢阈值的时间比野生型长 65%。这些结果表明，EPS 产量对细菌生长动力学和细菌细胞密度有显着影响，进而影响基于膜的生物膜反应器的性能。在这两种情况下，较低的 EPS 产量与更高效的处理过程相关。