New recombinant cold-adapted and organic solvent tolerant lipase from psychrophilic Pseudomonas sp. LSK25, isolated from Signy Island Antarctica

• Main Authors: Salwoom, Leelatulasi, Raja Abdul Rahman, Raja Noor Zaliha, Salleh, Abu Bakar, Mohd Shariff, Fairolniza, Convey, Peter, Mohamad Ali, Mohd Shukuri
• Format: Article in Journal/Newspaper
• Language: English
• Published: MDPI 2019
• Subjects: Antarctic; South Orkney Islands; Signy Island; Signy Station; Antarc*; Antarctica
• Online Access: http://psasir.upm.edu.my/id/eprint/38418/; http://psasir.upm.edu.my/id/eprint/38418/1/38418.pdf; https://www.mdpi.com/1422-0067/20/6/1264

In recent years, studies on psychrophilic lipases have become an emerging area of research in the field of enzymology. The study described here focuses on the cold-adapted organic solvent tolerant lipase strain Pseudomonas sp. LSK25 isolated from Signy Station, South Orkney Islands, maritime Antarctic. Strain LSK25 lipase was successfully cloned, sequenced, and over-expressed in an Escherichia coli system. Sequence analysis revealed that the lipase gene of Pseudomonas sp. LSK25 consists of 1432 bp, lacks an N-terminal signal peptide and encodes a mature protein consisting of 476 amino acids. The recombinant LSK25 lipase was purified by single-step purification using Ni-Sepharose affinity chromatography and had a molecular mass of approximately 65 kDa. The final recovery and purification fold were 44% and 1.3, respectively. The LSK25 lipase was optimally active at 30 °C and at pH 6. Stable lipolytic activity was reported between temperatures of 5–30 °C and at pH 6–8. A significant enhancement of lipolytic activity was observed in the presence of Ca2+ ions, the organic lipids of rice bran oil and coconut oil, a synthetic C12 ester and a wide range of water immiscible organic solvents. Overall, lipase strain LSK25 is a potentially desirable candidate for biotechnological application, due to its stability at low temperatures, across a range of pH and in organic solvents.