A 1.1 × 10⁶ Da acidic exopolysaccharide (EPS) was purified from an extremely halophilic archaeon Haloarcula hispanica ATCC33960 with a production of 30 mg L⁻¹ when grown in AS-168 medium, which mainly composed of mannose and galactose with a small amount of glucose in a molar ratio of 55.9 : 43.2 : 0.9. Two glycosyltransferase genes (HAH_1662 and HAH_1667) were identified to be responsible for synthesis of the acidic EPS. Deletion of either HAH_1662 or HAH_1667 led to loss of the acidic EPS. The mutants displayed a different cell surface morphology, retarded growth in low salty environment, an increased adhesion, and swimming ability. Our results suggest that biosynthesis of the acidic EPS might act as an adaptable mechanism to protect the cells against harsh environments.

中文翻译：

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一种来自西班牙嗜盐藻ATCC33960的酸性胞外多糖和两个负责其合成的基因。

 从极嗜盐古细菌Haloarcula hispanica ATCC33960中纯化出1.1×10 ⁶ Da酸性胞外多糖（EPS），在AS-168培养基中生长时产生30 mg L ^-1，主要由甘露糖和半乳糖组成，少量葡萄糖的摩尔比为55.9∶43.2∶0.9。确定了两个糖基转移酶基因（HAH_1662和HAH_1667）负责酸性EPS的合成。删除HAH_1662或HAH_1667导致酸性EPS损失。突变体显示出不同的细胞表面形态，在低盐环境中生长迟缓，粘附力增强，并且具有游泳能力。我们的结果表明，酸性EPS的生物合成可能是一种适应性机制，可保护细胞免受恶劣环境的影响。