Cloning, Expression and Characterization of a Lipase Gene from Marine Bacterium Pseudoalteromonas lipolytica SCSIO 04301 Cloning, Expression and Characterization of a Lipase Gene from Marine Bacterium Pseudoalteromonas lipolytica SCSIO 04301

Absract A lipase gene, lip1233, isolated from Pseudoalteromonas lipolytica SCSIO 04301, was cloned and expressed in E. coli. The enzyme comprised 810 amino acid residues with a deduced molecular weight of 80 k Da. Lip1233 was grouped into the lipase family X because it contained a highly conserved motif GHSLG. The recombinant enzyme was purified with Ni-NTA affinity chromatography. The optimal temperature and p H value of Lip1233 were 45℃ and 8.0, respectively. It retained more than 70% of original activity after being incubated in p H ranging from 6.0 to 9.5 for 30 min. It was stable when the temperature was below 45℃, but was unstable when the temperature was above 55℃. Most metal ions tested had no significant effect on the activity of Lip1233. Lip1233 remained more than original activity in some organic solvents at the concentration of 30%(v/v). It retained more than 30% activity after incubated in pure organic solvents for 12 h, while in hexane the activity was nearly 100%. Additionally, Lip1233 exhibited typical halotolerant characteristic as it was active under 4M Na Cl. Lip1233 powder could catalyze efficiently the synthesis of fructose esters in hexane at 40℃. These characteristics demonstrated that Lip1233 is applicable to elaborate food processing and organic synthesis