Improved production of Pseudomonas sp. ECU1011 acetyl esterase by medium design and fed-batch fermentation.
Bioprocess Biosyst Eng
; 35(3): 323-31, 2012 Mar.
Article
in En
| MEDLINE
| ID: mdl-21792565
ABSTRACT
We optimized culture medium and batch-fed fermentation conditions to enhance production of an acetyl esterase from Pseudomonas sp. ECU1011 (PSAE). This enzyme enantioselectively deacetylates α-acetoxyphenylacetic acid. The medium was redesigned by single-factor and statistical optimization. The addition of ZnSO(4) enhanced enzyme production by 37%. Yeast extract concentration was directly associated with the enzyme production. The fermentation was scaled up in a 5-l fermenter with the optimized medium, and the correlations between enzyme production and dissolved oxygen, pH, and feeding strategy were investigated. The fermentation process was highly oxygen-demanding, pH sensitive and mandelic acid-inducible. The fermentation pH was controlled at 7.5 by a pH and dissolved oxygen feedback strategy. Feeding mandelic acid as both a pH regulator and an enzyme inducer increased the enzyme production by 23%. The results of the medium redesign experiments were confirmed and explained in fed-batch culture experiments. Mathematical models describing the fermentation processes indicated that the enzyme production was strongly associated with cell growth. The optimized pH and dissolved oxygen stat fed-batch process resulted high volumetric production of PSAE (4166 U/l, 7.2-fold higher than the initial) without enantioselectivity decline. This process has potential applications for industrial production of chiral mandelic acid or its derivatives.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Pseudomonas
/
Acetylesterase
/
Bacterial Proteins
/
Bioreactors
/
Models, Biological
Type of study:
Prognostic_studies
Language:
En
Journal:
Bioprocess Biosyst Eng
Journal subject:
BIOTECNOLOGIA
/
ENGENHARIA BIOMEDICA
Year:
2012
Document type:
Article