Production and optimization of recombinant GDH enzyme in bioreactor system for biotechnological applications and the effects of graphene oxide (GO) nanostructures on enzyme activity

Enzymes are biocatalysts that carry out target-specific biochemical reactions in living organisms. The fact that enzymes perform various biotransformations increases their use in industrial processes. Glucose dehydrogenase (GDH), one of the enzymes of value for the enzyme industry, is a candidate enzyme to be used commercially in various tests for the detection of blood sugar levels due to its ability to reduce glucose. In this direction, recombinant production, activity studies of the GDH enzyme were carried out in the thesis study. Recombinant production was carried out by transferring the expression vector (pET-28a(+)-GDH) cloned from the GDH gene to the E. coli BL21(DE3) expression strain. SDS-PAGE and activity studies showed that GDH enzyme had high expression, purity, activity and specificity. Enzyme synthesis and characterization (XRD and FTIR) of various nanostructures (GO, rGO, GO-Fe, GO-Pt, GO-Ni and GO-Fe-Histidine) were carried out in the second stage of the thesis study. The effects on its activity were examined. It was observed that nanostructures reduced enzyme activity in the concentration range studied. As a result, it can be stated that the recombinantly produced GDH enzyme can be used in glucose test studies when compared with the reference enzyme in terms of the parameters examined.