Public defence in Biotechnology, Lic.Sc. (Tech.) Noora Salonen

Public defence from the School of Chemical Engineering, Department of Bioproducts and Biosystems
Doctoral hat floating above a speaker's podium with a microphone

Title of the thesis: Expression of recombinant proteins in Lactococcus lactis – an application in D-tagatose production

Doctoral student: Lic.Sc. (Tech.) Noora Salonen
Opponent: Professor Per Saris, University of Helsinki
Custos: Professor Alexander Frey, Aalto University School of Chemical Engineering, Department of Bioproducts and Biosystems

Protein expression in Lactococcus lactis – an application in tagatose production 

Proteins are essential for life and are present in all cells, performing countless functions. By recombinant protein expression in a suitable host organism, it is possible to gain much higher yields of the desired protein more cost-effectively than by isolating them from natural sources. Recombinant proteins can be used, for example, as biological drugs, or in various enzymatic manufacturing processes.
The same host, such as the often-used Escherichia coli bacterium, is not suitable to produce all proteins. Lactococcus lactis is a commercially attractive host for recombinant protein production with many potential applications, for example, in the food and pharmaceutical industries. Production of recombinant proteins requires a suitable expression system, and in this study, two new inducible recombinant protein expression systems for L. lactis were developed. One of them was used to produce arabinose isomerase from Bifidobacterium longum, and the enzyme was characterized.
Tagatose is a rare sugar with health-promoting effects and can be used as a low-calorie sweetener. However, the production costs still limit its commercial use. This study investigated tagatose production using resting L. lactis cells harboring recombinant B. longum arabinose isomerase enzyme.

Thesis available for public display 10 days prior to the defence 
Contact details:
Lic.Sc. (Tech.) Noora Salonen
[email protected] 

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