| Autor: |
Chuan, Wang, Heng-Chuan, Liu, Xiao-Fang, Pei, Qian, Yu, Chao-Wu, Zhang |
| Rok vydání: |
2009 |
| Předmět: |
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| Zdroj: |
Sichuan da xue xue bao. Yi xue ban = Journal of Sichuan University. Medical science edition. 40(1) |
| ISSN: |
1672-173X |
| Popis: |
To construct recombinant Lactococcus lactis strains exhibiting high beta-galactosidase activity in non-fusion way, and study their enzyme activities and enzyme secretion rates.The recombinant plasmids pMG36e-lacZ 1.1480 and pMG36e-lacZ wch9901 which could express beta-galactosidase from Lactobacillus delbrueckii subsp. bulgaricus in non-fusion way in Escherichia coli were obtained and transformed into Lactococcus lactis subsp. lactis MG1363. The beta-galactosidase activity of resulting recombinant L. lactis in different incubation periods and lactose concentrations, and their enzyme secretion rates in different culture conditions were examined.Recombinant L. lactis carrying pMG36e-lacZ wch9901 (MG1363/pMG36e-lacZ wch9901) exhibited the highest beta-galactosidase activity. Its enzyme activity was (16.95 +/- 0.09) U/mg pro, which was 2.75 folds of that of the native counterpart; recombinant L. lactis reached its enzyme producing peak after grown for 24 h; decreased enzyme activity of recombinant L. lactis were observed when incubated in medium containing lactose; the beta-galactosidase expressed by recombinant strains could be secreted into the culture medium, and the highest secretion rate (27.09 +/- 0.05)% was observed when the culture medium contained 20 g/L of lactose and without erythromycin.High level expression of non-fusion beta-galactosidase with secretion in recombinant L. lactis strains was obtained. This will be very helpful for the further developing of live delivery bacteria of beta-galactosidase. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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