Fed-batch production of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) in soluble form in Escherichia coli and its purification and characterization

• Optimized conditions for improving soluble TRAIL yields in Escherichia coli were proposed.
• 4.14 ± 0.19 g/L of soluble TRAIL was achieved by pH-stat fed-batch cultivation.
• Recombinant TRAIL was purified by an efficient two-step chromatographic procedure.
• 4313.5 mg of TRAIL with 98.1% purity was obtained from 2.3 L of cell broth.
• Purified recombinant TRAIL was in homotrimeric form and with strong cytotoxicity.

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising anticancer agent. The aim of this study is to produce large quantities of highly pure and bioactive recombinant human TRAIL. Here, TRAIL was expressed in soluble form by pH-stat fed-batch cultivation and purified using a rapid and simple two-step chromatographic procedure. To improve the soluble yield, expression of TRAIL in Escherichia coli was induced with low IPTG concentration (0.1 mM) at low temperature (28 °C) supplemented with ZnSO4 (0.5 mM), using glycerol as carbon source. Under the optimized conditions, 4.14 ± 0.19 g/L of TRAIL in soluble form was achieved at 19 h without pure oxygen. To purify the recombinant TRAIL, we developed an efficient two-step chromatographic procedure including affinity chromatography and cation-exchange chromatography, especially improved the cation-exchange chromatography using a combination of pH and NaCl gradients strategy. Consequently, 4313.5 mg of target protein with high purity (98.1%) was obtained from 2.3 L of cell broth. Our results also showed that the purified TRAIL was with ordered secondary and tertiary structures, in homogeneous form and with strong cytotoxicity.