High-throughput DNA extraction strategy for fecal microbiome studies.

Area of Science:

• Microbiome research
• Gut microbiota analysis
• Molecular biology techniques

Background:

• Large-scale microbiome studies require high-throughput DNA isolation methods for fecal samples.
• Standardization of DNA extraction protocols is essential to minimize bias and improve consistency in next-generation sequencing (NGS) based gut microbiota profiling.
• Existing protocols may introduce variability, impacting the reliability of microbiome data across different studies and laboratories.

Purpose of the Study:

• To identify an optimal, rapid, and reproducible DNA isolation method for processing thousands of fecal samples.
• To evaluate the impact of different sample preservatives and pre-treatment protocols on DNA yield, quality, and taxonomic profiles.
• To assess the suitability of the Chemagic 360 instrument and Magnetic Separation Module I (MSMI) for automated, high-throughput fecal DNA extraction.

Main Methods:

• Comparison of two sample preservatives (OMNIgeneGUT, DNA/RNA shield fluid) and four pre-treatment protocols (bead beating, tube/plate format, proteinase K incubation).
• DNA extraction using the Chemagic DNA Stool 200 H96 kit on human fecal samples (adult, senior, infant) with technical replicates, negative controls, and a ZymoBIOMICS Gut Microbiome Standard.
• Assessment of DNA quantity (Qubit), purity/quality (gel electrophoresis), and taxonomic signatures (16S rRNA gene sequencing, V3V4 and V4 regions).

Main Results:

• Bead beating significantly increased bacterial diversity, particularly for hard-to-lyse Gram-positive genera like *Blautia*, *Bifidobacterium*, and *Ruminococcus*.
• Preservatives showed minor differences in bacterial abundances, and both were feasible for sample handling with low variation in taxonomic signatures.
• The selected protocol, including bead beating, demonstrated reproducibility in DNA yield and taxonomic profiles, with the 96-format enabling automation for large sample collections.

Conclusions:

• A standardized DNA isolation protocol incorporating bead beating is necessary for comprehensive gut microbiome analysis, especially for detecting low-abundance or difficult-to-lyse bacteria.
• The Chemagic 360 and MSMI instrument facilitate high-throughput processing of fecal samples, crucial for large-scale microbiome studies.
• Optimization of DNA extraction methods is vital for consistent and reliable gut microbiota profiling using 16S rRNA gene sequencing.