Summary There is a growing need for new formulations of carriers with better protection for bacterial inoculum. One of the newer techniques in inoculum making is encapsulation method. With this method, the whole bacterial cells are immobilized in defined space – matrix, where the cells are protected from environmental activities before use. Encapsulation of the inoculum was performed with ionic gelation method. The alginate-based microparticles (500-600 µm) containing viable B. japonicum strain were solidified in CaCl2. The initial number of viable bacteria in every sample was 9.0 log CFU/ml. Chitosan coated particles had a higher mortality rate than non-coated particles, with 1.3 log CFU/ml in lyophilized and wet microparticles stored at room temperature. High viability of B. japonicum was registered in wet particles stored at constant −20°C for thirty days with a viability rate of 8.84 log CFU/ml.

Endophytic bacteria colonize the internal tissue of the plant usually forming beneficial association with their host. The main aim of this study was to genotypically and phenotypically characterize endophytic bacteria isolated from roots, stems and nodules of two soybean cultivars (AFZG Ana and Gabriela). A total of 29 endophytes were isolated from three different tissues of soybean. Genotypic characterization included rrs genes sequencing. Among soybean endophytes five different genera of bacteria were identified: Pseudomonas spp., Sphingomonas spp., Bradyrhizobium spp., Rhizobium spp., and Agrobacterium spp. Most of the isolates were Gram negative, rod-shaped, without capability of capsule production. The variability of the phenotypic characteristics of isolates was demonstrated, as well as the resistance to adverse environmental conditions such as high temperature, increased salt content, and low and high pH values. Most strains showed tolerance to the specific antibiotics. Most of the catalase positive isolates belong to Bradyrhizobium or Rhizobium spp., while the catalase negative isolates belong to the Pseudomonas, Sphingomonas and Agrobacterium spp. It was also shown that 85% of the tested isolates were oxidase negative while those that were positive belong to the Pseudomonas spp. Further characterization of endophytes is needed to determine their influence on plant growth.