INNOVATIVE BACTERIAL BIOINOCULANTS BASED ON BIOPOLYMERS

INNOVATIVE BACTERIAL BIOINOCULANTS BASED ON BIOPOLYMERS

Abstrakt

The increasing pressure for green farming techniques demands the implementation of groundbreaking practices that target yields comparable by conventional fertilizers, thus strengthening the environmental integrity of farming operations and preventing the lasting deterioration of productive soil. Among these novel technologies can be found also biofertilizers that inoculate soil with plant growth-promoting rhizobacteria (PGPR), which is a diverse group of microorganisms recognized for their beneficial contributions (nitrogen fixation, phosphate solubilization, the synthesis of siderophores and phytohormones), alongside the production of protective exopolysaccharide alginate and intracellular polyhydroxyalkanoates that function as carbon storage under stress conditions. The research presents an innovative method for biofertilizer production that uses Azotobacter vinelandii for in situ self-encapsulation within a gel carrier through the crosslinking of alginate, which is synthesized during the bacterial cultivation process. This creative approach simplifies our preparation methods, offering new possibilities for costsaving measures and increasing the overall effectiveness of the process. To support this theory, selected bacterial strains underwent gelation trials in settings that support the development of alginate gel, employing 2% (w/w) CaCl₂ as a cross-linker. Azotobacter vinelandii CCM 289 was chosen based on its superior alginate production, efficient gelation performance, and demonstrated potential for synthesizing indole-3-acetic acid and siderophores. A total of three cultivation experiments were carried out on the lettuce, incorporating various carrier compositions (cells in PBS; gel excluding cells; gel including cells; freeze-dried gel with cells; negative control). Primary variations between cultivation conditions were attributed to the disparity in soil quality and fluctuations in irrigation rates. The growth experiment was carried out under controlled irrigation and illumination. As the quality of the soil and the frequency of irrigation decreased throughout the experimental trials, the disparities among the various groups became increasingly apparent, demonstrated by a notable improvement in fundamental growth metrics (fresh/dry weight, lengths of plant components), in addition to favorable modifications in the composition of the soil microbiome.

The increasing pressure for green farming techniques demands the implementation of groundbreaking practices that target yields comparable by conventional fertilizers, thus strengthening the environmental integrity of farming operations and preventing the lasting deterioration of productive soil. Among these novel technologies can be found also biofertilizers that inoculate soil with plant growth-promoting rhizobacteria (PGPR), which is a diverse group of microorganisms recognized for their beneficial contributions (nitrogen fixation, phosphate solubilization, the synthesis of siderophores and phytohormones), alongside the production of protective exopolysaccharide alginate and intracellular polyhydroxyalkanoates that function as carbon storage under stress conditions. The research presents an innovative method for biofertilizer production that uses Azotobacter vinelandii for in situ self-encapsulation within a gel carrier through the crosslinking of alginate, which is synthesized during the bacterial cultivation process. This creative approach simplifies our preparation methods, offering new possibilities for costsaving measures and increasing the overall effectiveness of the process. To support this theory, selected bacterial strains underwent gelation trials in settings that support the development of alginate gel, employing 2% (w/w) CaCl₂ as a cross-linker. Azotobacter vinelandii CCM 289 was chosen based on its superior alginate production, efficient gelation performance, and demonstrated potential for synthesizing indole-3-acetic acid and siderophores. A total of three cultivation experiments were carried out on the lettuce, incorporating various carrier compositions (cells in PBS; gel excluding cells; gel including cells; freeze-dried gel with cells; negative control). Primary variations between cultivation conditions were attributed to the disparity in soil quality and fluctuations in irrigation rates. The growth experiment was carried out under controlled irrigation and illumination. As the quality of the soil and the frequency of irrigation decreased throughout the experimental trials, the disparities among the various groups became increasingly apparent, demonstrated by a notable improvement in fundamental growth metrics (fresh/dry weight, lengths of plant components), in addition to favorable modifications in the composition of the soil microbiome.

Alginate, Bioinoculant, Lettuce, PGPR, Polyhydroxyalkanoates

Alginate, Bioinoculant, Lettuce, PGPR, Polyhydroxyalkanoates

SÚKENÍK, M.; ČERNAYOVÁ, D.; KALINA, M.; HLAVÁČKOVÁ, B.; SEDLÁČEK, P.; OBRUČA, S.

01.02.2026

Università di Bologna

ALMA MATER STUDIORUM - Università di Bologna - Via Zamboni, 33 - 40126 Bologna

AGRICULTURAL CHEMISTRY WINTER SCHOOL SOIL-PLANT-MICROBIOME FUNCTIONALITY AND ADAPTATION TO ANTHROPOGENIC STRESS AND CLIMATE CHANGE BOOK OF ABSTRACT

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