Enhanced production of ATP-binding cassette protein exporter-dependent lipase by modifying the growth medium components of Pseudomonas fluorescens

The industrially-important thermostable lipase, TliA, was extracellularly produced in the recombinant Pseudomonas fluorescens by the homologous expression of TliA and its cognate ABC protein exporter, TliDEF. To increase the secretory production of TliA, we optimized the growth temperature and the culture medium of P. fluorescens. The total amount and the specific productivity of lipase was highest at 25 °C of cell growth temperature, although maximal cell growth was observed at 30 °C. Using the culture medium composed of 20 g dextrin l⁻¹, 40 g Tween 80 l⁻¹ and 30 g peptone l⁻¹, TliA was produced at a level of 2,200 U ml⁻¹ in a flask culture. The TliA production increased about 3.8-fold (8,450 U ml⁻¹) in batch fermentation using a 2.5 l fermentor, which was about 7.7-fold higher than that of previously reported TliA production.