光合细菌 Rhodopseudomonas acidophila 的胞外聚合物的提取讨论摘要：采纳了五种不同的方法——EDTA、NaOH、H2SO4、热提取和高速离心，对光合细菌Rhodopseudomonas acidophila 的胞外聚合物（EPS）进行提取。结果表明，EDTA 法是一种比较好的提取方法，提取效率高，对细胞破坏小。EPS 中的多糖、蛋白和核酸含量分别为6.5、58.4、5.4 mg/g 干重。EDTA 的适宜提取时间 1～3h，用量约为 2.8 g/g 干重。采纳不同的提取方法，提取的 EPS 中的组分含量大不相同。本文还采纳了两种方法检查细胞的破坏程度，一种是测定核酸含量，一种是测定光合细菌提取前后 UV-Vis 光谱和 EPS 的 UV-Vis光谱，两种方法的结果一致。EDTA 提取方法中，细菌的 UV－Vis 峰强度在提取前后没有变化，EPS 溶液中也没有新的色素峰出现，说明基本没有细胞被破坏。由于 UV－Vis 光谱测定方便快速，可以用来监测在 EPS 提取过程中细胞的溶解情况。关键词：胞外聚合物；光合细菌；UV-Vis 光谱；蛋白；核酸；多糖；提取Extraction of the extracellular polymeric substances from a photosynthetic bacterium Rhodopseudomonas acidophilaAbstract: Among the five methods for extracting extracellular polymeric substances (EPS) from Rhodopseudomonas acidophila using EDTA, NaOH, H2SO4, heating and high speed centrifugation, EDTA extraction was found to be the most effective method because of higher extraction efficiency and lower cell lysis. The contents of the major components of EPS from R. acidophila, i.e., carbohydrate, protein and nucleic acid, were 6.5, 58.4 and 5.4 mg/g dry cell, respectively. The feasible extraction time was 1-3 h and the EDTA dosage was about 2.8 g/g dry cells for EDTA extraction. Two methods, i.e. the content of nucleic acid and UV-Vis spectrum, were used to evaluate cell lysis during extraction. The absorption peaks for photosynthetic pigments in UV-Vis spectrum seemed no change prior to and after EDTA extraction, and no pigment peaks appeared in the spectrum of EPS, indicating that few...
