The extreme environments in the Xinjiang region have led most bacteria to evolve physiological and biochemical characteristics that resist environmental stresses (such as salt-alkali tolerance, cold tolerance, heat tolerance, and radiation tolerance).

Salt lakes are a type of extreme ecological environment rich in salt and alkali. The total number of salt lakes distributed in the Xinjiang region reaches 200, ranking among the top in China.

Li E. Y. et al. compared the microbial communities in 5 salt lakes, including Barkol Lake, Yiwu Lake, Ebinur Lake, Yanhu Lake, and Chaiwopu Lake. A total of 58 phyla, 68 classes, 138 orders, 253 families, and 560 genera of bacteria were screened out, among which Proteobacteria was the dominant phylum.

The dominant species and genera of bacteria in different salt lakes were all different, but the dominant genera were all related to halophilic and halotolerant genera. Meanwhile, with the increase of salt concentration in salt lakes, the microbial community undergoes succession from non-halotolerant microbial populations to halotolerant or halophilic populations.

The highly robust bacteria screened from the salt lake environment are excellent chassis for the development of microbial cell factories.

Chen G. Q. et al. isolated and screened 2 strains of moderately halophilic bacteria from Xinjiang salt lake samples, named Halomonas TD01 and Halomonas campaniensis LS21 respectively. They used these strains to construct chassis cells for fermentative production of polyhydroxyalkanoates (PHA), and successfully realized unsterilized open fermentation.

This project directly draws inspiration from the Silk Road's core principles: connection, adaptation, and sustainability. Where merchants once transported silk—a material valued for its strength and versatility—we transport plasmids: molecular "silk threads" of DNA that encode multi-gene stress resistance, offering industrial strains the same adaptability that allowed Silk Road communities to flourish in diverse climates.

The SILK project (Stability-Integrated Industrialization Leveraging Key plasmids) addresses the critical challenge of environmental sensitivity in industrial fermentation by harnessing Xinjiang's extremophilic microbial resources. Xinjiang's arid landscapes, extreme temperature fluctuations, and saline-alkaline soils have fostered highly robust bacterial taxa, encoding natural plasmids with evolved stress-resistance mechanisms.

Our team isolates and sequences these plasmids to identify functional genetic elements (e.g., thermotolerance, pH stability), then constructs standardized expression modules for industrial strains. By integrating nature's evolutionary solutions into biofactory frameworks, SILK aims to enhance fermentation stability, reduce energy costs for environmental control, and expand synthetic biology's toolkit for extreme-condition applications—transforming Xinjiang's "microbial silk" into industrial resilience.

We subjected the bacterial strains isolated from the collected samples to stress environment cultivation, and employed the alkaline lysis method to extract plasmids from the stress-tolerant bacterial strains.

To test whether the robust function could be transferred, we used the engineered E. coli BL21 strain to construct recombinant engineered bacteria with the extracted plasmids, followed by stress test cultivation.

For further investigation into the mechanism underlying the robust function of the plasmids, we performed ORF (Open Reading Frame) prediction on the transferable plasmids. Subsequently, we constructed recombinant plasmids using the predicted ORF elements with robust function and introduced them into the PET28a vector to generate recombinant engineered bacteria.

To verify the robust function after transfer, we conducted stress tests on the recombinant engineered bacteria containing the ORFs and performed SDS-PAGE electrophoresis analysis.

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