Beet molasses based exponential feeding strategy for thermostable glucose isomerase production by recombinant Escherichia coli BL21 (DE3)


Angardi V., ÇALIK P.

JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY, vol.88, no.5, pp.845-852, 2013 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 88 Issue: 5
  • Publication Date: 2013
  • Doi Number: 10.1002/jctb.3910
  • Journal Name: JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.845-852
  • Keywords: exponential feeding, oxygen transfer, glucose isomerase, molasses, E, coli, T7 promoter, BENZALDEHYDE LYASE PRODUCTION, ALKALINE PROTEASE PRODUCTION, FED-BATCH FERMENTATIONS, XYLOSE ISOMERASE, ACETATE ACCUMULATION, OXYGEN-TRANSFER, BACILLUS-LICHENIFORMIS, THERMUS-THERMOPHILUS, CITRIC-ACID, GROWTH-RATE
  • Middle East Technical University Affiliated: Yes

Abstract

BACKGROUND: The effects of pretreated beet molasses based feeding strategies on thermostable glucose isomerase (GI) production by recombinant Escherichia coli BL21 (DE3) pLysS were investigated. RESULTS: The thermostable GI encoding gene of Thermus thermophilus (xylA) was recombined with pRSETA vector, and the pRSETA::xylA obtained was transferred into E.coli BL21 (DE3) pLysS and used for GI production. The highest soluble GI activity was obtained at t = 30 h, as A = 16 400 U L1 (20.6 U mg1 protein) under molasses based fed-batch operation, with a specific growth rate mu = 0.1 h1 (M-0.1); on the other hand, the highest cell concentration was obtained at mu = 0.15 h1 operation as 9.6 g L1 at t = 32 h. The highest oxygen uptake was 4.57 mol m3 s1 at M-0.1 operation. CONCLUSIONS: Molasses based fed-batch operations were more successful in terms of cell concentration and thermostable enzyme production due to the existence of a natural sugar inducer, galactose, in the molasses composition. This study demonstrates the significance of proper feeding strategy development for over-production of enzymes by recombinant E. coli strains. (c) 2012 Society of Chemical Industry