Increased Productivity and Antifreeze Activity of Ice-binding Protein from Flavobacterium frigoris PS1 Produced using Escherichia coli as Bioreactor

Ice-binding proteins (IBPs) inhibit the growth and recrystallization of intracellular ice, enabling polar organisms to survive at subzero temperatures. IBPs are promising materials in biomedical applications such as cryopreservation and the hypothermic storage of cells, tissues, and organs. In this study, recombinant IBP from the antarctic bacterium Flavobacterium frigoris PS1 (FfIBP) was produced by Escherichia coli used as bioreactor, to examine the feasibility of scale-up. Oxygen transfer was the most important factor influencing cell growth and FfIBP production during pilot-scale fermentation. The final yield of recombinant FfIBP produced by E. coli harboring the pET28a-FfIBP vector system was 1.6 g/L, 3.8-fold higher than that from the previously published report using pCold I-FfIBP vector system, and its thermal hysteresis activity was 2.5°C at 9.7 µM. This study demonstrates the successful pilot-scale production of FfIBP.