ИСТИНА

Formulation of inoculants based on plant growth-promoting rhizobacteria (PGPR) is the crucial issue for commercial inoculants. Successful commercialization of these strains is dependent on improvements and advancements in interdisciplinary research, large-scale production, formulation methods etc. [Tabassum et al., 2017]. This industrial process can determine the commercial success or failure of a biological agent that has outstanding performance in a research facility. Formulation is the industrial “secret art” of converting a promising laboratoryproven microorganism, carefully-cultivated by skilled specialists in carefully designed and supervised experiments into a commercial product used by common growers under uncontrolled field conditions [Bashan et al., 2014]. This study is focused on practical aspects of inoculations technology development based on rhizobacteria Bacillus RB15 and Pseudomonas RB43. Technology including cultivation, concentration and drying of PGPR to establish dry inoculants using beneficial PGPR has been developed. Application of contact drying was shown the most appropriate in compare with spray drying method in terms of survivability of the thermolabile microorganisms. Special emphasis was given to formulations drying using natural organic materials. Shortly after suspensions of bacteria are inoculated into the soil without a proper carrier, the bacteria population declines rapidly. This phenomenon, combined with poor production of bacterial biomass, difficulty sustaining activity in the rhizosphere, and the physiological state of the bacteria at application time, can prevent the buildup of a sufficiently large PGPB population in the rhizosphere. Humic substances, peat, and montmorillonite were used as carriers of thermolabile PGPR cells at drying and long-term storage. All components have proved to be an excellent matrix for immobilization of cells due to its biocompatibility, non-toxic nature, and reduced vulnerability to environment stresses which will provide prolonged action of bacterial preparation in field conditions. References: 1. Tabassum B., Khan A., Tariq M, Ramzan M., Khan M., Shahid N., Aaliya K. Bottlenecks in commercialization and future prospects of PGPR. Applied Soil Ecology (2017) 121: 102. 2. Bashan, Y., de-Bashan, L.E., Prabhu, S.R. et al. Advances in plant growth-promoting bacterial inoculant technology: formulations and practical perspectives (1998–2013). Plant Soil (2014) 378: 1.