Increase in stability of Fusarium heterosporum lipase

Thermostable lipases are useful for their industrial application. The present review focuses on the increase in thermostability of 1,3-positionally specific lipases from Fusarium heterosporum and Rhizopus oryzae. The Saccharomyces cerevisiae carrying F. heterosporum lipase cDNA produced two kinds of lipases, A and B. Lipase B was composed of one polypeptide (301 amino acids), and lipase A was composed of two polypeptides (275 and 26 amino acids) generated by the cleavage between Arg275 and Asp276 by a protease. Lipase B was more thermostable than lipase A, so it revealed that the C-terminal peptide (26 amino acids) is important for the stability. To produce only the thermostable lipase in S. cerevisiae, a mutant lipase (R275A, Arg275 → Ala) was constructed. The C-terminal peptide of R275A lipase was not cleaved, and its thermostability increased to the level of lipase B. When acidolysis of tripalmitin (PPP) with oleic acid (OA) was conduced at 50 °C using immobilized R275A lipase, the half-life of R275A lipase preparation was 370 d, which was significantly longer than those of industrially available immobilized lipases. R. oryzae lipase was also synthesized as prolipase (366 amino acids), which was then converted to mature lipase (269 amino acids) by the cleavage of the N-terminal prosequence (97 amino acids) by a protease. Prolipase was more stable against heating than mature lipase, and S. cerevisiae carrying a mutant lipase gene ( Arg−29 → Ala) produced only the thermostable lipase.