Production, purification, and characterization of cold-active lipase from the psychrotroph Pseudomonas sp. A6

Cold-active lipases are presently employed extensively in the detergent, chemical intermediate, fine chemical, food, and pharmaceutical industries. Seven cold-adaptive bacteria were isolated from the Mediterranean Sea near Alexandria, Egypt, and tested for their ability to produce cold-active lipase, with the highest activity at 10 °C. The most potent isolate was Pseudomonas sp. A6. To determine the most important variables, the bacterium was exposed to a necessary medium component and environmental factor screening using a single factor-at-a-time approach, followed by a multifactorial Plackett-Burman design strategy. After purification and characterization, the optimal activity levels for the cold-active lipase were figured out. Inoculation of Pseudomonas A6 under near optimum conditions using medium consisting of (g/L) peptone 7.14; soybean oil 7.5% (v/v); K₂HPO₄, 0.4; MgSO₄, 0.1; glucose 2; pH 8; and temperature 10 °C led to a maximum lipase activity anticipated to be 23.36 U/mL. Purified lipase showed the best activity and thermal stability at a pH of 8 and a temperature of 10 °C. The Pseudomonas A6 lipase tolerated the monovalent ions, while greater valence ions did not.