INVESTIGADORES
ROJAS Natalia Lorena
artículos
Título:
Optimization of the production of a polygalacturonase from Aspergillus kawachii cloned in Saccharomyces cerevisiae in batch and fed-batch cultures
Autor/es:
ROJAS N.L.; ORTIZ, G. E.;; CHESINI, M.; BARUQUE, D.J.; CAVALITTO, S. F.
Revista:
FOOD TECHNOLOGY AND BIOTECHNOLOGY
Editorial:
FACULTY FOOD TECHNOLOGY BIOTECHNOLOGY
Referencias:
Lugar: Zagreb; Año: 2011 vol. 49 p. 316 - 321
ISSN:
1330-9862
Resumen:
y
Polygalacturonases (PG; EC 3.2.1.15) catalyze the hydrolysis of pectin and/or pectic
acid and are useful for industrial applications such as juice clarification and pectin extraction.
Growth and heterologous expression of recombinant Saccharomyces cerevisiae which
expresses an acidic PG from Aspergillus kawachii has been studied in batch and fed-batch
cultures. Kinetics and stoichiometric parameters of the recombinant yeast were determined
in batch cultures in a synthetic medium. In these cultures, the total biomass concentration,
protein concentration, and enzyme activity achieved were 2.2 g/L, 10 mg/L, and 3 U/mL,
respectively, to give a productivity of 0.06 U/(mL.h). In fed-batch cultures, various strategies
for galactose feeding were used: (i) after a glucose growth phase, the addition of a
single pulse of galactose which gave a productivity of 0.19 U/(mL.h); (ii) after a glucose
growth phase, a double pulse of galactose at the same final concentration was added, resulting
in a productivity of 0.21 U/(mL.h); (iii) a simultaneous feeding of glucose and galactose,
yielding a productivity of 1.32 U/(mL.h). Based on these results, the simultaneous
feeding of glucose and galactose was by far the most suitable strategy for the production
of this enzyme. Moreover, some biochemical characteristics of the recombinant enzyme
such as a molecular mass of ~60 kDa, an isoelectric point of 3.7 and its ability to hydrolyze
polygalacturonic acid at pH=2.5 were determined.