Assessment of polymers for the formulation of legume inoculants

The survival of the Bradyrhizobium elkanii strains SEMIA 587 and SEMIA 5019 ( = 29W) used for soybean inoculation was evaluated in the biopolymer carrier xanthan together with Jatai gum for up to eight months of storage. Peat carrier was used for comparison. The synthetic polymers polyvinylpyrrolidone (PVP) and polyethyleneglycol (PEG) were added to the broth cultures which were injected into the peat and polymer carriers. Best results were obtained after the fourth month of storage with the mixture of the gums plus PVP broth, or without the additive, and these were superior to the gums plus PEG and to the peat carrier with or without PVP.