Banca de DEFESA: Jaqueline Carvalho de Almeida
Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.DISCENTE : Jaqueline Carvalho de Almeida
DATA : 30/11/2018
HORA: 08:00
LOCAL: Sala 1 do PPGF/UFRRJ
TÍTULO:
IMPROVEMENT OF A POLYMERIC INOCULATION CARRIER FOR DIAZOTROPHIC BACTERIAL FORMULATIONS EFFICIENT FOR SUGAR CANE
PALAVRAS-CHAVES:
Polymeric mixture, sustainability, plant growth promoting rhizobacteria, biological nitrogen fixation
PÁGINAS: 76
GRANDE ÁREA: Ciências Agrárias
ÁREA: Agronomia
SUBÁREA: Fitotecnia
ESPECIALIDADE: Manejo e Tratos Culturais
RESUMO:
The aim of this study was to improve a polymeric carrier based on carboxymethylcellulose (CMC) and starch for a bacterial inoculant formulation for sugarcane demonstrating desirable characteristics for the maintenance of cell viability and stability. Four types of starch and two of CMC were tested with MgO as the compatibilizing agent in the range of 0.1 to 1% in terms of dry basis. Three ratios of CMC / starch (80:20, 60:40 and 40:60) and three sterilization conditions (100 oC for 20 min and 121 oC for 30 and 60 min at 1 atm) were also evaluated. Maintenance of cell viability of Bradyrhizobium pachyrhizi, strain BR3262 and strains BR11281 from Gluconacetobacter diazotrophicus, BR11335 from Herbaspirillum seropedicae, BR11504 from H. rubrisubalbicans, BR11145 from Nitrospirillum amazonense and BR11366 from Parabulkholderia tropica was determined over a period of up to 168 days at room temperature . The BR3262 strain registered for cowpea at the Ministry of Agriculture, Livestock and Food Supply presented higher cell survival after 38 days of storage in a polymer blend compatibilized with 0.2 to 0.5% MgO. The increase of the MgO content correlated with the increase of carrier pH, being observed values in the range of 9.5 with one of the starches tested. The pH of the carriers formed by two of the four starches, C and D, remained between 7.5 and 8.0 after 180 days of blend preparation using 0.3% of MgO. Five BR3262 formulations were selected for being able to maintain approximately 8 x 107 CFU g-1 until 84 days after inoculation, which corresponds to approximately 40% of the total inoculated cells. After 168 days, these formulations presented a mean of 1.7 x 107 CFU g-1. Sterilization conditions did not influence viable cells number over the storage period. Effective diazotrophic strains for sugarcane inoculation (BR11335, BR11504, BR11145 and BR11366) were formulated in carriers produced with starch C. Cell viability lasted for 30 days of storage independent of the compatibilizing agent content. However, the survival of the G. diazotrophicus BR11281 strain was only possible after replacement of the crystal sugar a component of DYGS medium adaptation by a brown sugar during the production of the cell biomass. Maintenance of BR11281 cells was dependent on the CMC / starch ratio, accounting for about 1.3 x 108 CFU g-1 in the 40:60 and 80:20 mixtures after 90 days of storage. For the other strains, the results were independent of the CMC / starch ratio. After 150 days of storage, averages between 0.9 and 5.1 x 108 CFU g-1 were obtained. The CMC / starch polymer mixture represents an alternative to peat, but it is important to ensure its production according to standard procedures considering mainly the type of starch and the content of MgO as a compatibilizing agent.
MEMBROS DA BANCA:
Presidente - 345.536.817-49 - NORMA GOUVÊA RUMJANEK - EMBRAPA
Interno - 1104775 - ADELSON PAULO DE ARAUJO
Externo ao Programa - 2192757 - PAULO JANSEN DE OLIVEIRA
Externo à Instituição - MARCIA REED RODRIGUES COELHO - EMBRAPA
Externo à Instituição - GUSTAVO RIBEIRO XAVIER - EMBRAPA