This project systematically explored thermotolerant microorganisms as a chassis for the biosynthesis of specialized polyamines. The workflow began with the collection of hot spring samples across a temperature gradient (45°C to 75°C). Metagenomic analysis of these samples confirmed temperature as the core driver of microbial community structure and function, revealing a significant enrichment of polyamine synthesis pathways, particularly spermidine synthase, at the highest temperature (75°C). This led to the successful mining of key polyamine synthase genes.
Subsequently, isolated thermophilic Bacillus strains were subjected to a multi-omics analysis (transcriptomics, proteomics, metabolomics) under varying temperature stress (37°C, 45°C, 55°C). The integrated data revealed a coordinated cellular adaptation strategy involving:
1. Metabolic Reprogramming: Upregulation of energy and precursor metabolism to meet heightened demands.
2. Protein Homeostasis: Enhanced expression of chaperones and proteases to combat protein denaturation.
3. Membrane and Signaling Regulation: Adjustments in membrane transport and signal transduction.
Morphological analysis (SEM/TEM) visually confirmed these adaptations, showing cell elongation and structural remodeling with increasing temperature. Crucially, genes and pathways for polyamine biosynthesis, including key precursors like ornithine, were consistently upregulated under heat stress, underscoring the integral role of polyamines in the thermotolerance mechanism.