Cell growth and product formation are two critical processes in polysaccharide welan biosynthesis, but the conflict between them is often encountered. In this study, a temperature-dependent strategy was designed for two-stage welan production through overexpressing heat shock proteins in Sphingomonas sp. The first stage was cell growth phase with higher TCA cycle activity at 42 °C; the second stage was welan formation phase with higher precursor synthesis pathway activity at 37 °C. The highest welan concentration 37.5 g/L was achieved after two-stage process. Ultimately, this strategy accumulated welan yield of 79.2 g/100 g glucose and productivity of 0.62 g/L/h at 60 h, which were the best reported results so far. The duration of fermentation was shortened. Besides, rheological behavior of welan gum solutions remained stable at wide range of temperature, pH, and NaCl. These results indicated that this approach efficiently improved welan synthesis.

细胞生长和产物形成是威兰多糖生物合成的两个关键过程，但它们之间经常会遇到冲突。在这项研究中，通过在鞘氨醇单胞菌中过表达热休克蛋白，设计了一种温度依赖性策略，用于两阶段 Welan 生产sp. 第一阶段为细胞生长期，42℃时TCA循环活性较高；第二阶段是韦兰形成阶段，在 37°C 下具有较高的前体合成途径活性。经过两阶段工艺后，Welan 的最高浓度达到了 37.5 g/L。最终，该策略在 60 小时时累积了 79.2 g/100 g 葡萄糖的产量和 0.62 g/L/h 的生产率，这是迄今为止报告的最佳结果。发酵时间缩短。此外，威兰胶溶液的流变行为在很宽的温度、pH 值和 NaCl 范围内保持稳定。这些结果表明该方法有效地改善了韦兰合成。