Production and characterisation of recombinant α-L-arabinofuranosidase for production of xylan hydrogels.
Appl Microbiol Biotechnol
; 95(1): 101-12, 2012 Jul.
Article
em En
| MEDLINE
| ID: mdl-22460593
ABSTRACT
A recombinant strain of the protease-deficient, non-acidifying pH mutant Aspergillus niger D15 (A. niger D15 [abfB]) strain was developed to secrete α-L-arabinofuranosidase (AbfB) free of endo-1,4-ß-xylanases for selective hydrolysis of xylan into hydrogels. The A. niger D15 [abfB] strain expressed the α-L-arabinofuranosidase abfB gene under the transcriptional control of the glyceraldehyde-3-phosphate dehydrogenase promoter (gpd(P)) and glucoamylase terminator (glaA(T)) in fermentation cultures containing 10 % glucose. The yield, activity, purity, kinetics and ability of the recombinant AbfB to selectively hydrolyse xylans into hydrogels were assessed. The recombinant AbfB secreted in 125-mL shake flasks and 10-L bioreactor fermentation cultures had specific activities against ρ-nitrophenyl-α-arabinofuranoside of up to 4.4 and 2.7 U g⻹ (dry weight), respectively. In addition, the recombinant AbfB was present as a single protein species on silver-stained 10 % sodium dodecyl sulphate-polyacrylamide gel electrophoresis. The recombinant AbfB had optimal activity at 40-55 °C and pH 3.0 to pH 5.0 and was stable at temperature and pH of up to 60 °C and pH 6.0, respectively. About 20 % of the available arabinose in the xylan was released by the recombinant AbfB from the hydrolysis of low viscosity wheat and oat spelt arabinoxylans and about 9 and 5 % from bagasse and bamboo arabinoglucuronoxylans, respectively, that led to the formation of the hydrogels. Therefore, the constructed A. niger D15 [abfB] strain presented a microbial system for the production of recombinant AbfB with the required purity for the modification of xylans into hydrogels.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Aspergillus niger
/
Xilanos
/
Biotecnologia
/
Proteínas Recombinantes
/
Hidrogéis
/
Glicosídeo Hidrolases
Tipo de estudo:
Evaluation_studies
Idioma:
En
Revista:
Appl Microbiol Biotechnol
Ano de publicação:
2012
Tipo de documento:
Article
País de afiliação:
África do Sul