Banca de DEFESA: ALEX TEÓFILO DA SILVA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : ALEX TEÓFILO DA SILVA
DATE: 29/06/2022
TIME: 14:00
LOCAL: Online, em link a ser enviado
TITLE:

SOLUBILIZATION OF INORGANIC PHOSPHATE BY CAATINGA BACTERIA AND FUNGI

KEY WORDS:

Tricalcium phosphate; Alagoas semiarid; Screening; Macronutrient

PAGES: 75
BIG AREA: Ciências Agrárias
AREA: Agronomia
SUMMARY:

The Caatinga, unique biome in Brazil, has unique climatic characteristics, marked by high temperatures and low rainfall. The microorganisms of the Caatinga produce biologicals that are little explored and that can be strategic for agricultural use, such as phosphate solubilization. From this perspective, the objective was to evaluate the solubilization of inorganic phosphate by bacteria and fungi isolated from lichens from the Caatinga of Alagoas, as well as to quantify the solubilization under different stress conditions. The samples of crusty and fruity lichens were collected in the semiarid from Alagoas, in the municipality of Santana do Ipanema-AL, in an environmental protection region, the Tocaia reserve, and in an impacted region, the Serra do Gugi. A total of 129 fungi and 152 bacteria were evaluated, 08 of which were positive for inorganic phosphate solubilization at 25.0 °C. The strains were selected for the other tests and evaluated at different temperatures at 25.0, 30.0 and 35.0°C in solid medium and evaluated the solubilization index (IS), were: 1. LCB2, 5. LCB3, 6. LCB3, 7. LCB3, 8. LCB3, 15. LCB3, 9. LCB7, and 6. UVLCB5. It was observed that the bacteria were able to solubilize in the three temperature ranges. The isolates that had the highest (IS) were: 9. LCB7 (3.42); 1. LCB2 (4.83); 15. LCB3 (8.27) at 25.0°C, while at 30.0°C the isolate with the highest IS was 7. LCB3 (4.31); 1. LCB2 (5.33) and 15. LCB3 (12.05), at 35.0°C strain 15. LCB3 maintained the highest IS with (10.72) strain 1. LCB2 (4.58). Overall the halos ranged from 2.0 mm to 31 mm respectively. In the solubilization tests with the fungal isolates in NBRIP solid medium, there were no positive results. In liquid medium, 02 isolates 1. LCB2 and 9. LCB7 showed significant values for P quantification at 35.0°C the bacterium 9. LCB7 obtained an average release of soluble P of 520.53 mg/L, with pH reduction to 4.11 and at 30.0°C, the 1. LCB2 had an average release of soluble P of 563.73 mg/L, with a pH reduction to 4.14. Assays at different pH (5.0; 7.0 and 9.0) strain 1. LCB2 provided better solubilization at pH 9.0 with an average of 551.90 mg/L of soluble P and pH reduction to 3, 69 conferring better adaptability to the alkaline environment, the same occurred with strain 9. LCB7 that obtained greater solubilization at pH 9.0 with an average of 455.88 mg/L and reduction of pH 3.75; Isolate 9. LCB7 had the best solubilization average at pH 9.0 with an average release of soluble P of 455.88 mg/L with pH reduction to 4.75; the same occurred with isolate 1. LCB2, which obtained an average P release of 551.90 mg/L at pH 9.0 with a decrease in pH to 3.69. In tests with different concentrations of NaCl, both strains solubilized better up to 0.5 M, being 607.7 mg/L for strain 9. LCB7, strain 1. LCB2 conferred 236.34 mg/L of soluble P at 1.0 M. Regarding the different carbon sources tested, both strains maintained glucose as the best carbohydrate source with an average of 558.59 and 532.53 mg/L respectively. In contrast, for different nitrogen sources, strain 1. LCB2 conferred a higher level of soluble P with Urea 479.74 mg/L, strain 9. LCB7 had ammonium sulfate with the highest solubilization of 617.75 mg/L. In the kinetics, solubilization occurred exponentially for both bacteria, reaching 683.1 mg/L on the 7th day (144h) of incubation for 1. LCB2 and 667.82 mg/L for 9. LCB7. In the HPLC analysis, lactic, citric, succinic and fumaric acids were present, while 9. LCB7 only fumaric acid was not present in the 144 h of the assay, strain 1. LCB2 produced only citric acid until the 72 h period and produced the fumaric acid until the end of the experiment. The tested microorganisms isolated from Caatinga lichens have great potential for solubilizing inorganic phosphates, as well as being able to resist temperature levels, bringing new perspectives for field tests, with the possibility of a new inoculant for agricultural crops.

BANKING MEMBERS:
Presidente - 1506475 - ALYSSON WAGNER FERNANDES DUARTE
Interna - 2187545 - FLAVIA DE BARROS PRADO MOURA
Interno - 287.291.704-78 - JOÃO GOMES DA COSTA - EMBRAPA
Externo à Instituição - MICHEL RODRIGO ZAMBRANO PASSARINI - UFPR