Data/hora: 01/06/2024 02:18:36

Provedor de dados: | 58
País: | Brazil
Título: | Kinetics of high-Level of ß-glucosidase production by a 2-deoxyglucose-resistant mutant of Humicola lanuginosa in submerged fermentation
Autores: | Bokhari,Syed Ali Imran; Latif,Farooq; Rajoka,Muhammad Ibrahim.
Data: | 2008-12-01
Ano: | 2008
Palavras-chave: | SS-Glucosidase; Enthalpy; Entropy; Hemicellulose; Kinetics; Regulation; Submerged fermentation.
Resumo: | A 2-deoxyglucose-resistant mutant (M7) of Humicola lanuginosa was obtained by exposing conidia to γ-rays and permitting expression in broth containing 0.6% 2-deoxyglucose (DG) and cellobiose (1%) before plating on DG esculin-ferric ammonium citrate agar medium from which colonies showing faster and bigger blackening zones were selected. Kinetic parameters for enhanced ß-glucosidase (BGL) synthesis by M7 were achieved when corncobs acted as the carbon source. The combination between corncobs and corn steep liquor was the best to support higher values of all product formation kinetic parameters. Effect of temperature on the kinetic and thermodynamic attributes of BGL production equilibrium in the wild organismand M7was studied using batch process at eight different temperatures in shake-flask studies. The best performance was found at 45ºC and 20 g L-1 corncobs in 64 h. Both growth and product formation (17.93 U mL-1) were remarkably high at 45ºC and both were coupled under optimum working conditions. Product yield of BGL from the mutant M7 (1556.5 U g-1 dry corncobs) was significantly higher than the values reported on all fungal and bacterial systems. Mutation had thermo-stabilization influence on the organism and mutant required lower activation energy for growth and lower magnitudes of enthalpy and entropy for product formation than those demanded by the wild organism, other mesophilic and thermo-tolerant organisms. In the inactivation phase, the organisms needed lower values of activation energy, enthalpy and entropy for product formation equilibrium, confirming thermophilic nature of metabolic network possessed by the mutant organism.
Tipo: | Info:eu-repo/semantics/article
Idioma: | Inglês
Identificador: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822008000400024
Editor: | Sociedade Brasileira de Microbiologia
Relação: | 10.1590/S1517-83822008000400024
Formato: | text/html
Fonte: | Brazilian Journal of Microbiology  v.39 n.4 2008
Fonte: | info:eu-repo/semantics/openAccess