Self-entrapment of Azotobacter vinelandii cultures by gelation of their exopolysaccharides: A way towards next-generation bioinoculants

Self-entrapment of Azotobacter vinelandii cultures by gelation of their exopolysaccharides: A way towards next-generation bioinoculants

Článek WoS

Encapsulation of Plant Growth-Promoting Rhizobacteria (PGPR) in hydrogel carriers is a cutting-edge approach in developing agricultural bioinoculants, aiming to improve soil fertility and crop yield. Hydrogels provide protection against environmental stress, though traditional methods using external gel-forming agents limit economic viability. This study presents a novel approach, demonstrating the entrapment of Azotobacter vinelandii, a promising PGPR, within a gel matrix formed by Ca2+-induced crosslinking of its own exopolysaccharide, alginate. Among the five strains evaluated, A. vinelandii DSM 87, DSM 720, and DSM 13529 showed the highest alginate production, peaking at 4.9 +/- 0.6 g/L, 3.5 +/- 0.5 g/L, 3.8 +/- 0.8 g/L, and enabling stable gel formation by the fourth day of cultivation. These strains also exhibited molecular weights and chemical structures of alginate suitable for effective gelation upon Ca2+addition. Additionally, these strains demonstrated significant plant growth-promoting activities, including indole acetic acid production (up to 10.5 mu g/mL), siderophore release, and phosphate solubilization, further validating their potential for sustainable bioinoculant production. Finally, the viability of the A.vinelandii cells released from the gels was experimentally verified. Our findings support a feasible, cost-effective method for bioinoculant production that leverages A. vinelandii's intrinsic capabilities, offering a sustainable alternative to conventional agricultural practices.

Encapsulation of Plant Growth-Promoting Rhizobacteria (PGPR) in hydrogel carriers is a cutting-edge approach in developing agricultural bioinoculants, aiming to improve soil fertility and crop yield. Hydrogels provide protection against environmental stress, though traditional methods using external gel-forming agents limit economic viability. This study presents a novel approach, demonstrating the entrapment of Azotobacter vinelandii, a promising PGPR, within a gel matrix formed by Ca2+-induced crosslinking of its own exopolysaccharide, alginate. Among the five strains evaluated, A. vinelandii DSM 87, DSM 720, and DSM 13529 showed the highest alginate production, peaking at 4.9 +/- 0.6 g/L, 3.5 +/- 0.5 g/L, 3.8 +/- 0.8 g/L, and enabling stable gel formation by the fourth day of cultivation. These strains also exhibited molecular weights and chemical structures of alginate suitable for effective gelation upon Ca2+addition. Additionally, these strains demonstrated significant plant growth-promoting activities, including indole acetic acid production (up to 10.5 mu g/mL), siderophore release, and phosphate solubilization, further validating their potential for sustainable bioinoculant production. Finally, the viability of the A.vinelandii cells released from the gels was experimentally verified. Our findings support a feasible, cost-effective method for bioinoculant production that leverages A. vinelandii's intrinsic capabilities, offering a sustainable alternative to conventional agricultural practices.

Azotobacter vinelandii; Alginate; Polyhydroxyalkanoates; Hydrogels; Bioinoculants

Azotobacter vinelandii; Alginate; Polyhydroxyalkanoates; Hydrogels; Bioinoculants

ČERNAYOVÁ, D.; SÚKENÍK, M.; OBRUČA, S.; SMILEK, J.; KALINA, M.; MRÁZOVÁ, K.; HRUBANOVÁ, K.; KRZYŽÁNEK, V.; SEDLÁČEK, P.

17.04.2025

ELSEVIER SCI LTD

London

0144-8617

Carbohydrate Polymers

360

C

Spojené království Velké Británie a Severního Irska

1

11

11

https://www.sciencedirect.com/science/article/pii/S0144861725003881