Bioflocs: A novel bioformulation of PGPR cells with higher degree of stress tolerance

Abstract

The positive effect of different bioformulations, namely, vegetative cell, natural and artificial bioflocs of PGPR cells, namely, Azotobacter and Paenibacillus to various environmental stresses, namely, temperature, desiccation and salt tolerance was studied under in-vitro condition. It was observed that the natural and artificial bioflocs preparation of both Azotobacter and Paenibacillus cells exhibites higher tolerance to various environmental stresses, viz, temperature, desiccation and salt tolerance when compared to their respective vegetative cell formulations. Between the two bioflocs formulation, the natural biofloc formulation of both Azotobacter and Paenibacillus cells exhibited higher stress tolerance when compared to the artificial biofloc formulation. Between the two PGPR cells, the Paenibacillus cells in natural biofloc formulation exhibited higher stress tolerance than Azotobacter cells. It was hypothesized that the “EPS mediated natural biofloc formulation” of PGPR cells exhibited higher tolerance to environmental stresses when compared to the respective “EPS deficient artificial biofloc and vegetative cell” formulations.