Screening, characterization and flocculating property of carbohydrate polymer from newly isolated Enterobacter cloacae WD7
Screening, characterization and flocculating property of carbohydrate polymer from newly isolated Enterobacter cloacae WD7
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DOI：
10.1016/j.carbpol.2006.03.011
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发表时间：
2006-11-02
影响因子：
11.2
通讯作者：
Kennedy, J. F.
中科院分区：
文献类型：
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作者：
Prasertsan, P.;Dermlim, W.;Kennedy, J. F.
从5家海产品加工厂的回收污泥中分离出188株产碳水化合物聚合物细菌。其中3株分离菌株鉴定为阴沟肠杆菌WD7、聚集肠杆菌WD50和产碱假单胞菌WD22。阴沟肠杆菌WD7在培养3天后产生的粘稠培养液絮凝活性最高，粗聚合物产率为2.27 g/L。通过95%乙醇沉淀、透析和冷冻干燥对该聚合物进行部分纯化。它是一种由中性糖（29.4%）、醛酸（14.2%）和氨基糖（0.93%）组成的酸性杂多糖。傅里叶红外光谱分析表明，其官能团中存在羟基、羧基、羰基和甲氧基。DSC热分析表明，该多糖在300℃时结晶转变和结晶熔点（T-m）。该多糖溶于水，不溶于任何有机溶剂；在二价阳离子存在的碱性条件下发生胶凝，其中铜作为CuSO4的胶凝效果最好。絮凝性能研究表明，该多糖在4 ~ 60℃、pH 5 ~ 7条件下稳定。多糖浓度为2 mg/L， CaCl2浓度为40 mM，对高岭土具有协同絮凝作用。此外，在CaCl2存在的情况下，该多糖可以在较宽的pH （pH 2-8）和温度（4-50℃）范围内对高岭土悬浮液进行絮凝。(c) 2006 Elsevier Ltd.版权所有。
A total of 188 carbohydrate polymer-producing bacterial strains were isolated from recycled sludge of five seafood processing plants. Among three selected isolates, identified as Enterobacter cloacae WD7, Enterobacter agglomerans WD50 and Pseudomonas alcaligenes WD22. E. cloacae WD7 generated a viscous culture broth exhibiting the highest flocculating activity and a crude polymer yield of 2.27 g/L after 3 days cultivation. Partial purification of this polymer was performed by precipitation with 95% ethanol, dialysis and freeze-drying. It was characterized as an acidic heteropolysaccharide, composed of neutral sugars (29.4%), uronic acids (14.2%) and amino sugars (0.93%). The functional group analysis by FT-IR spectroscopy showed the presence of hydroxyl, carboxyl, carbonyl and methoxyl groups. Thermal analysis by DSC showed the crystalline transition and the crystalline melting point (T-m) at 300 degrees C. This polysaccharide was soluble in water and insoluble in any organic solvents tested; gelation occurred under alkaline conditions in the presence of divalent cations in which copper as CuSO4 gave the best result. Studies on the flocculation property revealed that this polysaccharide was stable at 4-60 degrees C and pH 5-7. The optimal concentrations for the flocculating activity were 2 mg/L polysaccharide and 40 mM CaCl2 which played the synergistic effect on kaolin flocculation. Moreover, this polysaccharide could flocculate the kaolin suspension over a wide range of pH (pH 2-8) and temperature (4-50 degrees C) tested in the presence of CaCl2. (c) 2006 Elsevier Ltd. All rights reserved.