南极海冰细菌胞外多糖的助凝作用及红外光谱分析

利用酒精沉淀结合氯仿和丁醇脱蛋白法,从南极海冰细菌Pseudoaheromonas sp.Bsi20310发酵液中制备得到该菌株所产的胞外多糖(Exopolysaccharide,Bsi20310 EPS)粗品.以Bsi20310 EPS为助凝剂,可以明显改善铁盐对模拟水溶性染料活性艳红X-3B废水的混凝效果,在pH 10左右,Fe(Ⅲ)浓度0.98 mmol·L-1条件下加入150 mg·L-1 Bsi20310 EPS,脱色率由16%提高到84%.利用傅里叶变换红外光谱法(FTIR)分析比较Bsi20310 EPS、Fe(Ⅲ)混凝剂-Bsi20310 EPS絮体及Fe(Ⅲ)混凝剂-Bsi20310 EPS-活性艳红X-3B絮体的官能团,图谱显示,Bsi20310 EPS含有丰富的-OH、-COOH及糖苷键等活性基团;当Bsi20310 EPS与Fe(Ⅲ)混凝剂作用后,3 429 cm-1处尖峰变成宽峰,2 921 cm-1处峰形减弱或消失,1 650cm-1处锐峰变成钝峰,1 242 cm-1处峰出现轻微红移,1 151～1 038 cm-1范围内杂多峰变成单一尖峰,表明-OH、-COOH及糖苷键是发生反应的主要官能团.研究结果预示着Bsi20310 EPS可以作为一种安全有效的微生物助凝剂.

FTIR Spectrum and Coagulation Enhancement of Exopolysaccharide Secreted by an Antarctica Bacterium Pseudoalteromona sp. Bsi20310

Bsi20310 exopolysaccharide (Bsi20310 EPS) was secreted by a bacteria named Pseudoalteromonas sp. Bsi20310, isolated from Antarctic Sea ice. Crude Bsi20310 EPS was prepared by precipitation of the culture solution with ethanol, with proteins removed by using chloroform and butanol preparatorily. The results showed that Bsi20310 EPS improved the FeCl3 coagulation performance on synthetic water-soluble dye reactive red X-3B dyeing wastewater, obviously. The optimum coagulation enhancement of Bsi20310 EPS expressed by decolorization rate is from 16% to 84%, at pH near 10, Fe(Ⅲ) concentration of 0.98 mmol·L-1 and Bsi20310 EPS concentration of 150 mg·L-1, respectively. Fourier transform infrared spectroscopy (FTIR) was used to investigate the functional groups of Bsi20310 EPS, Fe(Ⅲ)-Bsi20310 EPS floc and Fe(Ⅲ)-Bsi20310 EPS-reactive red X-3B floc. The spectra showed that Bsi20310 EPS contained a large number of functional groups such as —OH, —COOH and glycosidic bond. Some certain functional groups of Bsi20310 EPS changed being combined with Fe(Ⅲ) hydrolysate. For instance, narrow peaks at 3 429 and 1 650 cm-1 became wide; the peak at 2 921 cm-1 weakened or disappeared; the peak at 1 242 cm-1 red-shifted slightly; peaks in the region of 1 151-1 038 cm-1 became single and sharp, etc. The change in spectra indicated that —OH, —OOH and glycosidic bond might be the main functional groups. The study suggested a bright prospect of Bsi20310 EPS performing as an approach to safe and effective microbial coagulation enhancement.