The production of extracellular polysaccharides (EPS) by haloarchaeal members, with novel and unusual physicochemical properties, is of special importance and has the potential for extensive biotechnological exploitation. An extremely halophilic archaeon, Haloferax sp. BKW301 (GenBank Accession No. KT240044) isolated from a solar saltern of Baksal, West Bengal, India has been optimized for the production of EPS under batch culture. It produced a considerable amount (5.95 g/L) of EPS in the medium for halophiles with 15% NaCl, 3% glucose, 0.5% yeast extract, and 6% inoculum under shake flask culture at 120 rpm. The purified EPS, a homopolymer of galactose as revealed by chromatographic methods and Fourier‐transform infrared spectroscopy, is noncrystalline (CIxrd, 0.82), amorphous, and could emulsify hydrocarbons like kerosene, petrol, xylene, and so forth. Moreover, the polymer is highly thermostable (up to 420°C) and displayed pseudoplastic rheology. Biologically, the EPS was able to scavenge DPPH (2,2‐diphenyl‐1‐picrylhydrazyl) radical efficiently and inhibit the proliferation of the Huh‐7 cell line at an IC50 value of 6.25 µg/ml with a Hill coefficient of 0.844. Large‐scale production of this thermostable, pseudoplastic homopolysaccharide, therefore, could find suitable applications in industry and biotechnology.

中文翻译：

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由 Haloferax sp. 产生的生物活性胞外同多糖的生产和表征。BKW301

盐古菌成员生产的胞外多糖 (EPS) 具有新颖和不寻常的物理化学性质，具有特殊的重要性，并具有广泛的生物技术开发潜力。一种极度嗜盐的古细菌，Haloferax sp。BKW301（GenBank 登录号 KT240044）从印度西孟加拉邦 Baksal 的一个日光盐场中分离出来，已针对分批培养下的 EPS 生产进行了优化。它在含有 15% NaCl、3% 葡萄糖、0.5% 酵母提取物和 6% 接种物的嗜盐菌培养基中在 120 rpm 的摇瓶培养中产生了大量 (5.95 g/L) 的 EPS。纯化的 EPS 是一种半乳糖的均聚物，通过色谱方法和傅里叶变换红外光谱显示，是非结晶的（CIxrd，0.82）、无定形的，并且可以乳化碳氢化合物，如煤油、汽油、二甲苯、等等。此外，该聚合物具有高度的热稳定性（高达 420°C）并显示出假塑性流变性。在生物学上，EPS 能够有效清除 DPPH (2,2-diphenyl-1-picrylhydrazyl) 自由基并抑制 Huh-7 细胞系的增殖，IC50 值为 6.25 µg/ml，希尔系数为 0.844。因此，大规模生产这种耐热、假塑性同多糖可以在工业和生物技术中找到合适的应用。