Humic Acid Removal Breakthrough: Enhanced Soil DNA Extraction Kit for Complex Environmental Samples

As microbiome research continues to expand, both 16S rRNA sequencing and metagenomic sequencing have become essential tools across environmental science, agriculture, gut microbiome research, food safety, and industrial biotechnology.

However, regardless of the downstream sequencing strategy, success begins with one critical step: obtaining high-quality, inhibitor-free DNA.

Complex samples such as soil, feces, sludge, compost, fermentation materials, and environmental swabs often contain large amounts of humic acids, polysaccharides, polyphenols, proteins, and other PCR inhibitors. These contaminants can significantly reduce DNA yield, inhibit amplification, compromise sequencing quality, and ultimately affect biological interpretation.

source:Blaser 2016

To address these challenges, Yeasen introduces the Enhanced Soil DNA Extraction Kit (Cat#18527ES)—a next-generation extraction solution designed to deliver high-yield, high-purity DNA from difficult environmental and microbiome samples.

Featuring an optimized lysis chemistry, powerful inhibitor-removal technology, and highly efficient DNA purification workflow, the kit enables reliable DNA extraction for both second-generation and long-read sequencing applications.

Why DNA Extraction Remains the Bottleneck in Microbiome Research

Challenge	Impact on Downstream Analysis
High humic acid content	PCR inhibition and reduced library quality
Polysaccharides and polyphenols	Poor DNA purity and inaccurate quantification
Incomplete microbial lysis	Low DNA recovery and biased microbial profiles
DNA degradation	Reduced sequencing performance
Complex sample matrices	Poor reproducibility between samples

Whether performing 16S amplicon sequencing or shotgun metagenomics, DNA quality directly influences sequencing success and biological interpretation.

One Kit for Seven Major Sample Types

Unlike conventional soil DNA kits, the Enhanced Soil DNA Extraction Kit has been optimized for a wide range of challenging sample matrices.

Sample Type	Compatible Samples	Typical Applications
Soil	Agricultural soil, forest soil, saline soil, wetland sediment, orchard soil, black soil, red soil, sandy soil	Soil microbiome studies, metagenomics, pathogen detection, ecological surveys
Feces	Human, livestock, poultry, aquatic animal feces	Gut microbiome analysis, disease association studies, pathogen tracing
Intestinal Contents	Animal gastrointestinal contents	Nutrition studies, probiotic research, microbiota colonization analysis
Organic Fertilizers	Compost, manure, microbial fertilizers	Functional strain identification, fertilizer quality assessment
Fermentation Samples	Fermentation broth, solid-state fermentation substrates	Fermentation monitoring, strain identification, contamination control
Environmental Swabs	Laboratory, farm, industrial and public environment surfaces	Environmental monitoring and pathogen surveillance
Water Filter Membranes	Surface water, wastewater, aquaculture and drinking water samples	Water microbiome analysis and pathogen detection

Key Advantages

• Superior Inhibitor Removal: Superior Impurity Removal: Effectively eliminates humic acids, polysaccharides, and polyphenols to prevent PCR and sequencing inhibition. Fully compatible with NGS and third-generation sequencing.
• High Yield & Purity: Ensures thorough cell lysis and high nucleic acid recovery. Delivers stable OD260/280 ratios with no protein or polysaccharide residues.
• Excellent DNA Integrity: Gentle lysis process effectively preserves genomic DNA integrity, making it ideal for both NGS and third-generation sequencing.
• Broad Sample Compatibility: Delivers pure extraction results even for challenging, high-humic acid samples.
• Low Background Bacteria: Unique filtration process ensures purity with no residual background bacteria.

Application Data

Case Study 1: High-Humic-Acid Black Soil Samples

Four black soil samples containing high levels of humic substances were processed using the Enhanced Soil DNA Extraction Kit.

After adding the precipitation solution, humic acids are significantly adsorbed and removed.

To evaluate the effectiveness of the proprietary precipitation solution, one sample was processed using PBS instead of the precipitation reagent. 

Sample	Treatment Method	Concentration (ng/μL)	A260/230	A260/280
1	PBS	45.1	1.34	0.64
1	Precipitation Solution	136.05	1.73	1.65
2	Precipitation Solution	125.96	1.68	1.44
3	Precipitation Solution	131.83	1.66	1.42
4	Precipitation Solution	118.87	1.67	1.38

 Table 1: Soil DNA Concentration and Purity 

 

Compared with PBS treatment, the proprietary precipitation solution:

• Increased DNA yield by approximately 3-fold
• Significantly reduced humic acid contamination
• Improved A260/230 and A260/280 purity ratios
• Produced cleaner DNA suitable for downstream amplification

 

Case Study 2: High-Humic-Acid Sludge Samples

Sludge samples were extracted in parallel using the 18527ES Enhanced Soil DNA Extraction Kit, Supplier M's reagents, and Supplier J's reagents, combined with the Yeasen 48-channel automated nucleic acid extractor. The elution volume was uniformly set to 70 μL.

Figure 2. Comparison of DNA extraction performance from high-humic-acid sludge samples.

The results showed that the 18527ES group achieved high nucleic acid yield. The agarose gel electrophoresis bands were bright and clear, with no obvious smearing or extraneous bands, indicating that its nucleic acid extraction efficiency and integrity for sludge samples were superior.

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