Efficiently scaled-up production of recombinant human elastin-like polypeptides using multiple optimization strategies

Abstract

Elastin-like polypeptides (ELPs) are biopolymers with repetitive amino acid sequences and are known for their biocompatibility and inverse transition cycling (ITC) properties; thus, they are ideal for biomedical applications. Owing to their low yield and tedious purification process with multiple rounds of ITC, no acceptable scaled-up production process has been developed. Here, for the first time, an efficient, low-cost process for the preparation of recombinant human elastin-like polypeptide (rhELP) is reported. This process leverages high-cell-density fermentation and hollow fibre membrane (HFM) filtration technology. First, we constructed an engineered strain of Escherichia coli (E. coli) with high expression of the rhELP protein, and a yield of 0.99 ± 0.03 g/L was achieved in shaker flasks by optimizing the induction temperature, induction OD₆₀₀, and inducer concentration via response surface methodology. Further optimization in 5 L, 200 L, and 500 L automated fermenters increased the yield to over 5.00 g/L, which meets the demands of industrial production. The efficient purification process included high-pressure homogenization, flocculation, salting out, HFM filtration, ion-exchange chromatography (IEC), and ultrafiltration and resulted in 99.83 % pure rhELP analyzed by size exclusion–high-performance liquid chromatography (SEC-HPLC), with a recovery rate of 80.40 %. The prepared protein was noncytotoxic and exhibited marked wound healing promotion both in vivo and in vitro. Thus, this study provides a universal paradigm for the industrial production of ELPs and other similar recombinant proteins, significantly advancing the commercialization of promising ELPs.