Gene cloning and catalytic characterization of cold-adapted lipase of Photobacterium sp. MA1-3 isolated from blood clam

A lipase-producing Photobacterium strain (MA1-3) was isolated from the intestine of a blood clam caught at Namhae, Korea. The lipase gene was cloned by shotgun cloning and encoded 340 amino acids with a molecular mass of 38,015 Da. It had a very low sequence identity with other bacterial lipases, with the exception of that of Photobacterium lipolyticum M37 (83.2%). The MA1-3 lipase was produced in soluble form when Escherichia coli cells harboring the gene were cultured at 18°C. Its optimum temperature and pH were 45°C and pH 8.5, respectively. Its activation energy was calculated to be 2.69 kcal/mol, suggesting it to be a cold-adapted lipase. Its optimum temperature, temperature stability, and substrate specificity were quite different from those of M37 lipase, despite the considerable sequence similarities. Meanwhile, MA1-3 lipase performed a transesterification reaction using olive oil and various alcohols including methanol, ethanol, 1-propanol, and 1-butanol. In the presence of t-butanol as a co-solvent, this lipase produced biodiesel using methanol and plant or waste oils. The highest biodiesel conversion yield (73%) was achieved using waste soybean oil and methanol at a molar ratio of 1:5 after 12 h using 5 units of lipase. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Bioscience & Bioengineering is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)