The characteristics of encapsulated whole cell beta-galactosidase

Authors
Citation
Cy. Oh et Jk. Park, The characteristics of encapsulated whole cell beta-galactosidase, BIOPROC ENG, 19(6), 1998, pp. 419-425
Citations number
13
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Biotecnology & Applied Microbiology
Journal title
BIOPROCESS ENGINEERING
ISSN journal
0178-515X → ACNP
Volume
19
Issue
6
Year of publication
1998
Pages
419 - 425
Database
ISI
SICI code
0178-515X(199812)19:6<419:TCOEWC>2.0.ZU;2-#
Abstract
We prepared encapsulated whole cell beta-galactosidase using E. coli. The c ell culture was divided into two steps for the cell accumulation inside the capsule and enzyme production in the cell. Growth and production media wer e used individually for this purpose. The dry cell weight of the free cell culture was increased 2.8 times by controlling the pH of the growth medium during cultivation. However, the weight of cells accumulated in the capsule reduced 40% with pH control. The dry cell weight increased with lactose co ncentration of the production medium for both cases of free and capsule cul tures. The dry cell weights were 1.5 g/l for free culture and 100 g/l in th e capsule when the lactose concentration of the production medium was 10 g/ l. The dry cell weight increased about 60% for both cases as the lactose co ncentration increased from 10 to 50 gn. The specific activity of whole cell enzyme decreased with lactose concentration from 5 to 1.4 unit/g dry cell for free culture and from 1.1 to 0.65 unit/g dry cell in the capsule. The v alue of Michaelis constant, K-m, of whole cell enzyme increased 3 times bec ause of the resistance of mass transfer through the capsule membrane. The c onstants of Michaelis-Menten equation for the whole cell enzyme in the caps ule were V-m: 0.0479 mM/min and K-m: 44.86 mM. These constants of the membr ane-free cells were V-m: 0.0464 mM/min and K-m: 15.64 mM. To increase the w hole cell enzyme activity, we treated encapsulated cells with organic solve nts. The activity of encapsulated whole cell enzyme was increased 3.5 times with the treatment of chloroform and ethanol. The activity of the encapsul ated whole cell enzymes was reserved after repeating the process 30 times.