Recombinant Elastin-Like Polymers: Production Optimization and Fermentation Scale-Up

Elastin-like polymers (ELP’s) are a group of polypeptides rooted in the repeating sequences from elastin, the extracellular elastic protein of higher animal. This family of polymers shows properties derived from the natural elastin itself, like striking mechanical behaviour when cross-linked. ELP’s are known to exhibit outstanding biocompatibility properties and smart behaviour towards temperature and often other stimuli, as well as self-assembly behaviour, showing phase transitions under and above an inverse transition temperature (ITT) in aqueous solutions. ITT can basically be affected by the mean polarity of the polymer, pH and molecular weight.

The properties presented by those materials and the possibility of further incorporate selected bioactivities, let foresee a great demand for the most cutting-edge applications. For example, the biocompatibility and smart behaviour are desired features for using in biomedical applications. Therefore, it’s easy to understand the need of large-scale protein production and the optimization of the process. The polymers presented here, are two of those examples. We present a polymer that possesses a sequence to improve cellular adhesion, designated as H-RGD6 (MW=60661 kDa), and a polymer presenting an osteoconductive behaviour, designated as HAP3 (MW=31877 kDa).

We determined the moment at which inoculation should occur is around an absorbance of 0.69. Estimated time for reaching this value is 10h, under the used experimental conditions. This work allowed us to conclude that the airflow and airflow pulses are a key factor in enhancing both growth of bacteria and polymer production and that great improvements can be obtained just by simple variations of it. On the other hand, knowing how they behave when subjected to different pHs it is possible to select a desired temperature, or a range of temperatures, for polymer processing, according to the requirements of specific applications.