Self-entrapment of Plant Growth Promoting Rhizobacteria by gelation of their exopolysaccharides – towards the next-generation bioinoculants

Encapsulation of Plant Growth Promoting Rhizobacteria (PGPR) in hydrogel carriers represents state-of-the-art in production of agricultural bioinoculants that are used to restore soil fertility and to enhance the yield of crops. The hydrogel matrix enhances bioinoculant performance by protecting the cells against various environmental stress factors that accompany its application, however, the encapsulation step provided by addition of an external gelation component reduces the economic feasibility of the bioinoculant production. The project proposes a novel concept of biofertilizers based on the entrapment of PGPR (from the genus Azotobacter) in the gel formed from alginate produced directly by the employed bacteria. The project will provide an in-depth study of all the essential steps – PGPR cultivation, gelation and drying of the bioinocullants and pilot screening of their bioactivity. The essential fundamental knowledge will be gained on the causal relationship between preparation procedure, structure and crucial properties of the bioinocullants based on this original strategy.