Effects of Commercial and Paenibacillus tarimensis Exopolysaccharides on Soil Aggregation and Hydraulic Properties of a Saline Clay Loam Soil

Lynda Smail ¹, Nadjette Djemouai ^2,3, Nadia Boukhelata ¹

⁰Equipe Biologie des Sols, Laboratoire de Biologie et Physiologie des Organismes (LBPO), Faculté des Sciences Biologiques, Université des Sciences et de la Technologie Houari Boumediene (USTHB), Bab Ezzouar, BP32, 16111, Algiers, Algeria.

Current Microbiology +

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September 26, 2025

View abstract on PubMed

Summary

Microbial exopolysaccharides (EPS) from Paenibacillus tarimensis REG 0201M significantly improve soil structure and stability in arid, saline soils. This bio-structuring amendment enhances aggregation, stability, and permeability, offering a solution for degraded lands.

Area Of Science

Soil Science
Microbiology
Biotechnology

Background

Soil structure and stability are critical for water retention, plant growth, and erosion control, especially in arid environments.
Microbial exopolysaccharides (EPS) are key biopolymers that enhance soil aggregation due to their unique rheological properties.
Degraded, saline soils in arid regions pose significant challenges for agriculture and ecosystem health.

Purpose Of The Study

To evaluate the efficacy of EPS-R1, derived from Paenibacillus tarimensis REG 0201M, as a soil amendment.
To assess the impact of EPS-R1 on the physical properties of calcareous, silty-clay, saline soil, including aggregate formation, stability, and permeability.
To compare the performance of EPS-R1 with commercial biopolymers like xanthan gum, gum Arabic, and agar-agar.

Main Methods

EPS-R1 was produced from Paenibacillus tarimensis REG 0201M and mixed with soil at concentrations of 0.2%, 0.4%, and 0.6% (w/w).
Soil aggregate formation, aggregate stability (disintegration percentage), mean weight diameter, and soil permeability were measured.
Water loss kinetics were analyzed to understand soil water retention forces.

Main Results

EPS-R1 significantly enhanced macroaggregation, reaching 86.89% of aggregates >2 mm at 0.6% concentration.
Aggregate stability improved markedly, with only 12.8% disintegration at 0.6% EPS-R1 compared to 29.8% for xanthan gum.
Soil permeability increased by 251% at 0.6% EPS-R1, and soil water retention forces decreased, enhancing aggregate stability.

Conclusions

EPS-R1 effectively transforms unstable soil into a highly stable structure, outperforming commercial xanthan gum.
The study demonstrates the potential of EPS-R1 as a potent bio-structuring agent for improving arid, degraded, and salt-affected soils.
EPS-R1 offers a sustainable solution for soil remediation and enhancing agricultural productivity in challenging environments.

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