TECHNOLOGICAL OPTIONS FOR THE PRODUCTION OF LACTOFERRIN

Abstract

Lactoferrin (LTF) is a multifunctional protein of the transferrin family present in human and other mammals’ milk. Global demand for originated protein is currently much higher than the supply, and lactoferrin remains the one of the most expensive proteins. Therefore, the development of cost efficient methods to produce lactofferin is extremely important. In this study, human lactoferrin is obtained in bacterial system. ltf gene, coding sequence of protein - human lactoferrin (hLTF), was cloned into the expression vector pET28a+, modified signal sequence IMKKTAIAIAVALAGFATVAQA AS. E.coli BL21DE3 strain was selected for expression. Productivity of the producing strain in regard to recombinant human lactoferrin was 30-35% of the cellular protein. The strain produced the recombinant lactoferrin in the form of inclusion bodies. The maximum yield of the target protein (including in soluble form) was achieved by culturing of the recombinant strain at 25°C, induction by 1.1 mM concentration of IPTG and 8-h period after induction. Optimization of solubilization and renaturation conditions allowed once to recover lactoferrin in a concentration of 2.9 mg/ml by the pulsed system. The protein of high purity at least 90% was obtained by means of affinity chromatography on Ni+-agarose.

Keywords

• lactoferrin
• milk protein
• gene
• E.coli