Oscillatory behavior of US -galactosidase enzyme activity in Escherichia coli during perturbed batch experiments
The behaviour of a wild-type and mutant strain of Escherichia coli under batch aerobic conditions were studied. In these experiments the bacteria were initially grown with lactose as the sole carbon source. When exponential growth on lactose was achieved, the batch was perturbed with D-glucose. Periodic off-line samples were taken from the fermentor and analyzed for US -galactosidase enzyme activity, D-glucose, and lactose. Continuous on-line measurements of optical density of fermentation media were also made. Oscillations in the measured enzyme activity were observed. Oscillatory behavior of US -galactosidase enzyme in E. coli was previously reported by Knorre. In his study cells were grown in D-glucose, washed, and then grown on lactose. Oscillations were attributed to the varying enzyme synthesis rate. In the present study the cells were grown initally on lactose, thus assuring high synthesis rates of US -galactosidase from the start. The oscillations observed after perturbation with glucose are pronounced and appear to be the result of combined changes in the substrate transport system and enzyme activity in addition to possible changes in enzyme synthesis rate. 10 references.
- Research Organization:
- Univ. of Delaware, Newark
- OSTI ID:
- 6281430
- Journal Information:
- Biotechnol. Bioeng.; (United States), Vol. 29:2
- Country of Publication:
- United States
- Language:
- English
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09 BIOMASS FUELS
ESCHERICHIA COLI
BATCH CULTURE
ENZYME ACTIVITY
GALACTOSIDASE
BIOSYNTHESIS
AEROBIC CONDITIONS
BENCH-SCALE EXPERIMENTS
CARBON
CHEMICAL ANALYSIS
FERMENTATION
GLUCOSE
GROWTH
LACTOSE
MUTANTS
ON-LINE MEASUREMENT SYSTEMS
OPACITY
OSCILLATIONS
SAMPLING
SUBSTRATES
ALDEHYDES
BACTERIA
BIOCONVERSION
CARBOHYDRATES
DISACCHARIDES
ELEMENTS
ENZYMES
GLYCOSYL HYDROLASES
HEXOSES
HYDROLASES
MICROORGANISMS
MONOSACCHARIDES
NONMETALS
O-GLYCOSYL HYDROLASES
OLIGOSACCHARIDES
ON-LINE SYSTEMS
OPTICAL PROPERTIES
ORGANIC COMPOUNDS
PHYSICAL PROPERTIES
SACCHARIDES
SYNTHESIS
550700* - Microbiology
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