Abstract: Through adding different concentration of Cu²⁺ in the biofilm reactor, the relationship between extracellular polymeric substance(EPS) secreted by biofilm and efficiency of copper removal by biofilm was studied. Biofilm tolerance of Cu²⁺ was better than activated sludge, but a high concentration of Cu²⁺ rapidly poisoned the biofilm. When Cu²⁺ < 2 mg·L^-1, Cu²⁺ inhibited biofilm secretion of EPS. Concentration of 2 mg·L^-1 < Cu²⁺ < 5 mg·L^-1, Cu²⁺ would increase the amount of EPS, while Cu²⁺ > 5 mg·L^-1, the biofilm system displayed serious instability. Comparing proteins/polysaccharide (PN/PS) value showed that the biofilm suffered inhibition by Cu²⁺. The biofilm would inhibit more extracellular polysaccharide secretion, and the biofilm resistance of Cu²⁺ indicated that the biofilm would secrete more extracellular protein. The amount of EPS had a good correlation with the enrichment ratio of Cu²⁺.

Key words: biofilm, copper stress, reactivity, extracellular proteins, extracellular polysaccharide

摘要： 利用自行设计的生物膜培养装置进行挂膜，通过向生物膜反应器中投加不同浓度的Cu²⁺，探讨生物膜上的胞外聚合物（extracellular polymeric substance， EPS）与生物膜去除金属铜之间的关系。研究结果表明：生物膜法较活性污泥法对Cu²⁺具有更好的耐受性；当Cu²⁺ < 2 mg·L^-1，Cu²⁺会抑制生物膜分泌EPS，在2 mg·L^-1 < Cu²⁺ < 5 mg·L^-1时，生物膜分泌EPS的量增加，当Cu²⁺ > 5 mg·L^-1，生物膜系统表现为严重的不稳定性；比较蛋白质（proteins，PN）/多糖（polysaccharide，PS）值发现，Cu²⁺对生物膜的抑制主要是对生物膜上胞外多糖的抑制，而生物膜对Cu²⁺的抵抗表现为分泌更多的胞外蛋白；EPS与Cu²⁺的富集率关系呈线性正相关。

关键词: 生物膜, 铜胁迫, 活性, 胞外蛋白, 胞外多糖