Harada T
Biochem Soc Symp. 1983;48:97-116.
Alcaligenes faecalis var. myxogenes 10C3, which we isolated from soil, produces a water-soluble and an insoluble extracellular polysaccharide. The former (succinoglycan) is composed of glucose, galactose, pyruvic acid and succinic acid (molar proportions 7:1:1:1) with (beta 1-3)-, (beta 1-4)- and (beta 1-6)-glucosidic linkages. The latter (curdlan) is composed entirely of (beta 1-3)-linked D-glucose and forms a resilient firm gel when heated in suspension. The organism also produces extracellularly a repeating-unit octasaccharide of succinoglycan and cyclic (beta 1-2)-D-glucan. These polymers or oligomers are also produced by many strains of Agrobacterium and Rhizobium. Spontaneous mutation in ability to produce these polysaccharides or oligosaccharides occurs in these strains. The structures of succinoglycan, and similar polymers containing riburonic acid or galactose as the end residue of the side chain, were elucidated by successive fragmentation with two special enzymes obtained from Cytophaga arvensicola followed by methylation analysis. It is interesting that the unit compound in the biosynthesis of succinoglycan is identical with the unit compound in the enzymic decomposition of the polymer. Studies on curdlan gel by X-ray, 13C n.m.r. and electron-microscopic analysis and other physicochemical methods showed that the molecular structure of curdlan changes from a single helix to a triple stranded helix on heat treatment at high temperature. Curdlan seems to be useful for making new types of jelly products and may also be useful in new procedures for food production. Interestingly, curdlan possesses marked antitumour activity. Extracellular isoamylase (EC 3.2.1.68; glycogen 6-glucanohydrolase) of Pseudomonas amyloderamosa SB 15, which we isolated from soil, is very useful for elucidation of the structure of amylopectin and glycogen, and also for the commercial production of amylose or maltose alone or in combination with beta-amylase. Maltose is useful as a sugar for injection, being better than glucose. Maltitol is easily produced from maltose by chemical reduction and is used as a low-calorie sweetener. The isoamylase is also effective for enhancing the production of glucose from starch by the action of glucoamylase.
粪产碱杆菌黏液变种10C3是我们从土壤中分离得到的，它能产生一种水溶性胞外多糖和一种不溶性胞外多糖。前者（琥珀聚糖）由葡萄糖、半乳糖、丙酮酸和琥珀酸组成（摩尔比为7:1:1:1），具有（β1-3）-、（β1-4）-和（β1-6）-糖苷键。后者（凝胶多糖）完全由（β1-3）连接的D-葡萄糖组成，在悬浮液中加热时会形成有弹性的坚固凝胶。该菌还能在胞外产生琥珀聚糖的重复单元八糖和环状（β1-2）-D-葡聚糖。许多农杆菌属和根瘤菌属的菌株也能产生这些聚合物或寡聚物。这些菌株会出现产生这些多糖或寡糖能力的自发突变。通过用从田野纤维黏菌中获得的两种特殊酶进行连续片段化，然后进行甲基化分析，阐明了琥珀聚糖以及侧链末端残基含有核糖醛酸或半乳糖的类似聚合物的结构。有趣的是，琥珀聚糖生物合成中的单位化合物与该聚合物酶促分解中的单位化合物相同。通过X射线、13C核磁共振和电子显微镜分析以及其他物理化学方法对凝胶多糖凝胶的研究表明，凝胶多糖的分子结构在高温热处理时会从单螺旋变为三股螺旋。凝胶多糖似乎可用于制造新型果冻产品，也可能在新的食品生产工艺中有用。有趣的是，凝胶多糖具有显著的抗肿瘤活性。我们从土壤中分离得到的解淀粉假单胞菌SB 15的胞外异淀粉酶（EC 3.2.1.68；糖原6-葡聚糖水解酶）对于阐明支链淀粉和糖原的结构非常有用，也可用于单独或与β-淀粉酶联合商业生产直链淀粉或麦芽糖。麦芽糖作为注射用糖很有用，比葡萄糖更好。麦芽糖醇可通过化学还原很容易地从麦芽糖中制得，用作低热量甜味剂。该异淀粉酶对通过葡糖淀粉酶的作用提高淀粉产葡萄糖量也有效。
