Immobilization of Bradyrhizobium and Azospirillum in alginate matrix for long time of storage maintains cell viability and interaction with peanut

CESARI ADRIANA; PAULUCCI NATALIA; YSLAS E; DARDANELLI M.S

APPLIED MICROBIOLOGY AND BIOTECHNOLOGY

SPRINGER

Lugar: Berlin; Año: 2020 vol. 104 p. 10145 - 10164

0175-7598

Immobilization of PGPR for agricultural applications aims to provide temporary physical27 protection from stressful environmental conditions and for successful root colonization,28 release the cells gradually. In this work, we immobilized Bradyrhizobium sp. SEMIA614429 or Azospirillum brasilense Az39 cells in 2% alginate beads prepared by ionic gelation30 process, and then stored up to 12 months at 4 °C. Alginate matrix showed interaction with31 the immobilized bacteria (FTIR), allowed a constant release of cells and improved their32 viability and capability to interact with Arachis hypogaea. Cell number into beads reached33 107 CFU.bead-1, however viability decreased from 4 months of storage for Az39, while it34 was maintained up to 12 months for SEMIA6144, showing a low metabolic activity35 measured by the MTT assay. Adhesion of SEMIA6144 and Az39 from new beads to peanut36 root was 11.5% and 16%, respectively, higher than non-immobilized bacteria Peanut37 inoculation with 12 months storage SEMIA6144 beads significantly increased root length38 and biomass at 30 days of growth; and under restrictive water conditions (RWC) nodulation39 and total plant N content increased compared to liquid inoculation. Our results demonstrate40 that immobilization of SEMIA6144 and Az39 in alginate matrix is a potential alternative to41 enhance peanut growth even under RWC.