title: Beet molasses-based feeding strategy enhances recombinant thermostable glucose isomerase production by Escherichia coli BL21 (DE3).
abstract: The aim of this work was to develop an effective fed-batch feeding strategy to enhance recombinant glucose isomerase (r-GI) production by recombinant Escherichia coli BL21 (DE3) pLysS on an industrially relevant feedstock without the application of an exogenous inducer. Following the batch operation (0 < t < 7 H), the effects of pulse and/or continuous feeding of hydrolyzed beet molasses were investigated under five different feeding strategies. The two most promising strategies with respect to r-GI activity were (i) PM-0.05, designed with one pulse feed (t = 7 H) followed by a continuous feed and (ii) 2PMF-0.05, designed with two consecutive pulse feeds (t = 7 and 10 H) followed by a continuous feed. The continuous feeding of molasses for both fermentation strategies employed the same precalculated feeding rate, μo= 0.05 H-1. The maximum r-GI activities exhibited by PM-0.05 and 2PMF-0.05 were 29,050 and 30,642 U dm-3, respectively. On the one hand, compared to PM-0.05 r-GI activity reached its maximum within a shorter cultivation time (∆tmax= 2 H) at 2PMF-0.05, which could be preferable in terms of manufacturing costs and possible risks; on the other hand, PM-0.05 is a simpler fermentation regime compared to 2PMF-0.05 with respect to manipulations that should be considered in large-scale production.
authors.affiliation: Industrial Biotechnology and Metabolic Engineering Laboratory, Department of Chemical Engineering, Middle East Technical University, Ankara, Turkey.|Department of Biotechnology, Graduate School of Natural and Applied Sciences, Middle East Technical University, Ankara, Turkey.
authors.forename: Sena
authors.initials: S
authors.lastname: Yaman
authors.affiliation: Industrial Biotechnology and Metabolic Engineering Laboratory, Department of Chemical Engineering, Middle East Technical University, Ankara, Turkey.|Department of Biotechnology, Graduate School of Natural and Applied Sciences, Middle East Technical University, Ankara, Turkey.
authors.forename: Pınar
authors.initials: P
authors.lastname: Çalık
mesh_terms: D019747:Aldose-Ketose Isomerases / Q000096:biosynthesis*; D027461:Beta vulgaris / Q000378:metabolism*; D019149:Bioreactors; D004795:Enzyme Stability; D004926:Escherichia coli / Q000166:cytology / Q000378:metabolism*; D006868:Hydrolysis; D011994:Recombinant Proteins / Q000096:biosynthesis; D016963:Thermus thermophilus / Q000201:enzymology
chemical_list: D011994:Recombinant Proteins; D019747:Aldose-Ketose Isomerases; C023298:xylose isomerase
keywords: E. coli; bioprocess design; enzyme activity; enzyme production; fed-batch culture; glucose isomerase