Unusual composition of an exopolymer (EP) from an obligate halophilic bacterium Chromohalobacter canadensis 28 has triggered an interest in development of an effective bioreactor process for its production. Its synthesis was investigated in 2‐L bioreactor at agitation speeds at interval 600‐1000 rpm, at a constant air flow rate of 0.5 vvm; aeration rates of 0.5, 1.0, and 1.5 vvm were tested at constant agitation rate of 900 rpm. EP production was affected by both, agitation and aeration. As a result twofold increase of EP yield was observed and additionally increased up to 3.08 mg/mL in a presence of surfactants. For effective scale‐up of bioreactors mass transfer parameters were estimated and lowest values of KLa obtained for the highest productivity fermentation was established. Emulsification activity of EP exceeded that of trade hydrocolloids xanthan, guar gum, and cellulose. A good synergism between EP and commercial cellulose proved its potential exploration as an enhancer of emulsifying properties of trade emulsions. A pronounced lipophilic effect of EP was established toward olive oil and liquid paraffin. Cultivation of human keratinocyte cells (HaCaT) with crude EP and purified γ‐polyglutamic acid (PGA) showed higher viability than control group.

中文翻译：

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加拿大色盐杆菌 28 的不寻常外聚合物在生物反应器中的高产量和乳化活性


来自专性嗜盐细菌加拿大色盐杆菌 28 的外聚合物 (EP) 的不寻常组成引发了人们对开发有效的生物反应器生产工艺的兴趣。在 2 L 生物反应器中以 600-1000 rpm 的搅拌速度和 0.5 vvm 的恒定空气流量研究其合成；在 900 rpm 的恒定搅拌速率下测试了 0.5、1.0 和 1.5 vvm 的通气速率。 EP 生产同时受到搅拌和曝气的影响。结果观察到 EP 产率增加了一倍，并且在表面活性剂存在下进一步增加至 3.08 mg/mL。为了有效扩大生物反应器的传质参数，并确定了最高生产率发酵获得的 KLa 最低值。 EP 的乳化活性超过了商业亲水胶体黄原胶、瓜尔胶和纤维素。 EP和商业纤维素之间良好的协同作用证明了其作为商业乳液乳化性能增强剂的潜在探索。 EP 对橄榄油和液体石蜡具有明显的亲脂作用。用粗EP和纯化的γ-聚谷氨酸（PGA）培养人角质形成细胞（HaCaT）显示出比对照组更高的活力。