Production of recombinant β-galactosidase in bioreactors by fed-batch culture using DO-stat and linear control

Abstractβ-Galactosidase enzymes continue to play an important role in food and pharmaceutical industries. These enzymes hydrolyze lactose in its constituent monosaccharides, glucose and galactose. The industrial use of enzymes presents an increase in process costs reflecting in higher final product value. An alternative to enhance processes’ productivity and yield would be the use of recombinant enzymes and their large-scale fed-batch production. The overexpression of recombinant β-galactosidase from Kluyveromyces sp. was carried out in 2-L bioreactors using Escherichia coli strain BL21 (DE3) as host. Effect of induction time on recombinant enzyme expression was studied by adding 1 mM isopropyl thiogalactoside (IPTG) at 12 h, 18 h and 24 h of cultivation. Glucose feeding strategies were compared employing feedback-controlled DO-stat and ascendant linear pump feeding in bioreactor fed-batch cultivations. Linear feeding strategy with IPTG addition at 18 h of cultivation resulted in approximately 20 g/L and ...