Lantana charcoal as potent carrier material for Azotobacter chroococcum

Abstract

Azotobacter chroococcum is a universally accepted plant growth-promoting rhizospheric bacterium, which, as a biofertilizer, helps to increase the nitrogen level, solubilize the unavailable form of phosphorus, ensure growth-promoting metabolites, and control pathogenic microbes in the soil. A good strain of plant growth-promoting rhizobacteria (PGPR) needs to be produced, formulated, transported, stored, and distributed to the agriculture field. During all these operations, bacterial inoculants are transferred via a carrier material. One of the important challenges in biofertilizer technology is to ensure stability of the bacteria in the carrier. The study aimed to assess a novel carrier Lantana charcoal (LC; obtained from Lantana camara biomass), as compared to some currently available carriers. LC exhibited higher carbon content, low N2 content, neutral pH, and, above all, higher water-holding capacity, making it a suitable carrier material for A. chroococcum and possibly other PGPR. As a carrier, it showed no contamination during storage, exhibited the highest moisture content and moderate culture holding coefficient, and supported the highest colony-forming units per gram at the end of the storage period. Thus, LC cannot only serve as a better carrier, but its large-scale application would also ensure a reasonable use of this weed.