Description

Background

Polyamines are small aliphatic amines that are ubiquitous in all living organisms, playing crucial roles in stabilizing nucleic acids, regulating gene expression, and supporting stress adaptation. In addition to common polyamines such as putrescine, spermidine, and spermine, specialized polyamines—including long-chain and branched structures—have been identified mainly in thermophiles and certain plants. These rare molecules are of significant interest due to their potential applications in materials science, medicine, and agriculture.

Problem

However, conventional chemical synthesis of specialized polyamines is limited by low yield, high cost, and technical challenges. Synthetic biology offers a promising alternative, enabling sustainable and scalable production through microbial platforms. Thermophilic bacteria, especially Bacillus species, are ideal candidates for engineering such production systems because of their natural resilience to harsh conditions.

Project Goal and Significance

To establish a robust, thermotolerant microbial platform for the sustainable and scalable production of valuable specialized polyamines. This will be achieved by:

a) Exploiting Thermophiles as Chassis: Isolating native thermotolerant Bacillus strains.

b) Decoding Adaptation Mechanisms: Integrating multi-omics analyses to unravel the mechanisms of heat stress resistance and the integral role of polyamines.

c) Mining Biosynthetic Tools: Identifying and characterizing key genes and enzymes for specialized polyamine synthesis from high-temperature microbiomes.

This project is significant because it lays the foundation for the sustainable and scalable production of valuable specialized polyamines, which are of great importance in materials science, medicine, and agriculture.

Methodology Overview

Our project implements a systematic workflow to explore, characterize, and engineer thermotolerant microorganisms for efficient production of specialized polyamines. The methodology comprises the following key steps:

4.1 Sample Collection：Hot spring samples were collected from environments with varying temperatures to capture diverse microbial communities. These samples serve as input material for subsequent metagenomic and microbial analyses.

4.2 Metagenomic Sequencing and Gene Mining：Metagenomic DNA was extracted from collected samples and subjected to high-throughput sequencing. Bioinformatic pipelines were applied to identify candidate polyamine synthase genes and associated metabolic elements. Phylogenetic analyses and protein structural modeling were employed to categorize enzyme diversity and predict functionality.

4.3 Isolation and Genomic Characterization of Thermotolerant Strains: Under 37°C, 45°C, and 55°C, conduct transcriptomic, metabolomic, proteomic, and morphological studies.

4.4 Multi-Omics Profiling under Thermal Stress: Transcriptomic, proteomic, metabolomic, and morphological analyses were conducted on selected strains at 37°C, 45°C, and 55°C. Standardized protocols were applied to measure gene expression, protein abundance, metabolite levels, and cellular morphology, enabling assessment of thermotolerance mechanisms.

4.5 Integrative Data Analysis for Mechanistic Exploration: Multi-omics datasets were integrated using computational frameworks to characterize metabolic reprogramming, protein homeostasis, and signaling pathways under thermal stress. Polyamine-related regulatory networks were inferred to guide engineering strategies.

4.6 Design of Thermotolerant Microbial Chassis: Based on the collected data, a synthetic biology framework was established to construct microbial chassis capable of high-yield polyamine production. This involves the incorporation of identified thermophilic enzymes and regulatory modules, with the goal of developing scalable biosynthetic platforms.