Self encapsulation of plant growth-promoting bacteria Azotobacter vinelandii for their use as next-generation bioinoculants

Self encapsulation of plant growth-promoting bacteria Azotobacter vinelandii for their use as next-generation bioinoculants

Abstract

Azotobacter vinelandii is a plant-growth-promoting bacterium (PGPB), capable of synthesizing two different biopolymers with great application potential. Polyhydroxyalkanoates (PHA) are produced and stored in a form of intracellular granules, whereas alginate is produced extracellularly. Plant growth-promoting bacteria can be used as bio-inoculants to increase yields in agriculture. Encapsulation of bacteria into hydrogel-based carriers substantially improves the application potential of the bioinoculant as well as the viability and robustness of the bacterial culture. In this work, the alginate produced by the bacteria themselves was crosslinked with a calcium chloride solution to form a hydrogel carrier with encapsulated bacteria. This unconventional concept that we ter- med „self encapsulation“ simplifies bacterial encapsulation and production of hydrogel carriers, reduces the cost, and expands its usability in numerous applications. Firstly, we screened five strains of Azotobacter vinelandii to select those with a sufficient production capacity concerning alginate and PHA and suitable gelationproperties. Actually, the strain DSM 87 reached the highest concentration of the alginate (4.9 ± 0.6 g/l). The alginates produced by strains DSM 87 and DSM 720 demonstrated the best gelation properties. The bacterial entrapped in a gel matrix seemed to beviable and cultivatable. Hence, the preliminary results confirmed the feasibility and viability of the novel concept.

Azotobacter vinelandii is a plant-growth-promoting bacterium (PGPB), capable of synthesizing two different biopolymers with great application potential. Polyhydroxyalkanoates (PHA) are produced and stored in a form of intracellular granules, whereas alginate is produced extracellularly. Plant growth-promoting bacteria can be used as bio-inoculants to increase yields in agriculture. Encapsulation of bacteria into hydrogel-based carriers substantially improves the application potential of the bioinoculant as well as the viability and robustness of the bacterial culture. In this work, the alginate produced by the bacteria themselves was crosslinked with a calcium chloride solution to form a hydrogel carrier with encapsulated bacteria. This unconventional concept that we ter- med „self encapsulation“ simplifies bacterial encapsulation and production of hydrogel carriers, reduces the cost, and expands its usability in numerous applications. Firstly, we screened five strains of Azotobacter vinelandii to select those with a sufficient production capacity concerning alginate and PHA and suitable gelationproperties. Actually, the strain DSM 87 reached the highest concentration of the alginate (4.9 ± 0.6 g/l). The alginates produced by strains DSM 87 and DSM 720 demonstrated the best gelation properties. The bacterial entrapped in a gel matrix seemed to beviable and cultivatable. Hence, the preliminary results confirmed the feasibility and viability of the novel concept.

Azotobacter vinelandii, polyhydroxyalkanoates, alginate, gels, encapsulation

Azotobacter vinelandii, polyhydroxyalkanoates, alginate, gels, encapsulation

ČERNAYOVÁ, D.; SÚKENÍK, M.; SEDLÁČEK, P.; OBRUČA, S.

2022

25.11.2021

Vysoké učení technické v Brně, Fakulta chemická

Brno

978-80-214-6002-7

CHEMIE JE ŽIVOT 2021

1.

32

33

2

https://www.fch.vut.cz/vav/konference/sok/vystupy/sbornik-konference-2021-abstrakty-a5-pdf-p213391

http://hdl.handle.net/