Navegando por Autor "SARQUIS, Maria Inez de Moura"

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Acesso aberto (Open Access)
Biotransformation of sucrose into 5-hydroxy-2-hydroxymethyl-γ-pirone by Aspergillus flavus
(2010-09) FERREIRA, Nelson Rosa; SARQUIS, Maria Inez de Moura; ALVES, Claudio Nahum; SANTOS, Alberdan Silva
The sucrose hydrolysis and the preference of consumption of glucose instead of fructose were investigated for the production of 5-hydroxy-2-hydroxymethyl-γ-pyrone (HHMP) in the presence of Aspergillus flavus IOC 3974 cultivated in liquid Czapeck medium. Standardized 0.5g of pellets were transferred as inoculum into twelve conical flasks of 250 ml containing 100 ml of medium with different sucrose concentration, which was kept at 120 rpm and 28"C for 16 days without pH adjustment. Aliquots of 500μl of the broth culture were withdrawn at 24 h intervals and analyzed. The major yield of HHMP was 26g l-1 in 120g l-1 of sucrose. At these conditions, A. flavus produced an invertase capable of hydrolyzing 65% of total sucrose concentration in 24h, and an isomerase capable of converting fructose into glucose. In this work, it focused the preference for glucose and, then, of fructose by A. flavus and the strategy used to produce HHMP.
Acesso aberto (Open Access)
Production of L-asparaginase by filamentous fungi
(2004-08) SARQUIS, Maria Inez de Moura; OLIVEIRA, Edna Maria Morais; SANTOS, Alberdan Silva; COSTA, Gisela Lara da
L-asparaginase production was investigated in the filamentous fungi Aspergillus tamarii and Aspergillus terreus. The fungi were cultivated in medium containing different nitrogen sources. A. terreus showed the highest L-asparaginase (activity) production level (58 U/L) when cultivated in a 2% proline medium. Both fungi presented the lowest level of L-asparaginase production in the presence of glutamine and urea as nitrogen sources. These results suggest that L-asparaginase production by of filamentous fungi is under nitrogen regulation.