Optimization of cyclodextrin glycosyltransferase production from Klebsiella pneumoniae AS-22 in batch, fed-batch, and continuous cultures.
Production of a novel cyclodextrin glycosyltransferase (CGTase) from Klebsiella pneumoniae AS-22 strain, which converts starch predominantly to alpha-CD at high conversion yields, in batch, fed-batch, and continuous cultures, is presented. In batch fermentations, optimization of different operating parameters such as temperature, pH, agitation speed, and carbon-source concentration resulted in more than 6-fold increase in CGTase activity. The enzyme production was further improved by two fed-batch approaches. First, using glucose-based feed to increase cell density, followed by starch-based feed to induce enzyme production, resulted in high cell density of 76 g dry cell weight/L, although the CGTase production was low. Using the second approach of a single dextrin-based feed, 20-fold higher CGTase was produced compared to that in batch fermentations with media containing tapioca starch. In continuous operation, more than 8-fold increase in volumetric CGTase productivity was obtained using dextrin-based media compared to that in batch culture using starch-based media.
Gawande
Bharat N
BN
Biochemical Engineering Group, Chemical Engineering Division, National Chemical Laboratory, Pune 411 008, India. gawande@colorado.edu
Sonawane
Avinash M
AM
Jogdand
Vithal V
VV
Patkar
Anant Y
AY
D019149:Bioreactors / Q000382:microbiology*; D018929:Cell Culture Techniques / Q000379:methods*; D002455:Cell Division / Q000502:physiology; D003470:Culture Media / Q000378:metabolism; D003912:Dextrins / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism*; D005964:Glucosyltransferases / Q000096:biosynthesis* / Q000302:isolation & purification; D006863:Hydrogen-Ion Concentration; D007711:Klebsiella pneumoniae / Q000166:cytology / Q000201:enzymology* / Q000254:growth & development*; D011786:Quality Control; D013045:Species Specificity; D013213:Starch / Q000378:metabolism*; D013696:Temperature
D003470:Culture Media; D003912:Dextrins; D013213:Starch; D005964:Glucosyltransferases; C019963:cyclomaltodextrin glucanotransferase; D005947:Glucose