New Production Method of Exopolysaccharides Using Engineered Living Materials [EPS by ELM]

在DFG项目EPS by ELM中，提出了一种用于葡聚糖发酵的新型工程生物材料（ELM）。所谓的“ELM电池”由两个组件组成。第一组分是流变各向异性的、分级结构的细菌纤维素（BC）基质。该BC基质通过化学改性转化为pH指示剂，并反映ELM电池中的pH条件。第二种成分是产葡聚糖的乳酸菌肠膜明串珠菌，经过基因修饰，可在其直接环境中作为pH生物指示剂反应。它们被固定在功能化的BC基质上，从而永久保留在ELM细胞中。通过组合两种pH传感器，可以更好地显示葡聚糖生产过程中的pH变化。新的测试设置和pH监测促进了比搅拌罐发酵罐中更高的葡聚糖产率。来自ELM Cell发酵的高浓度葡聚糖溶液需要比传统工艺更少的溶剂进行纯化，从而使其更具可持续性。

In the DFG project EPS by ELM, a novel Engineered Living Material (ELM) for use in dextran fermentation is presented. The so-called "ELM cell" consists of two components. The first constituent is a rheotactically anisotropic, hierarchically structured bacterial cellulose (BC) matrix. This BC matrix is converted into a pH indicator via chemical modification and reflects the pH conditions in the ELM cell. The second component are the, dextran-producing lactic acid bacteria Leuconostoc mesenteroides, which are genetically modified to react in their immediate environment as a pH bioindicator. They are immobilized on the functionalized BC matrix and thereby permanently retained in the ELM cell. By combining both pH sensors, pH changes during dextran production are better displayed. The novel test setup and the pH monitoring facilitates higher dextran yields than in stirred tank fermenters. The highly concentrated dextran solution from ELM Cell fermentation requires less solvents for purification than conventional processes, thus making it more sustainable.