Effects of Olive Oil and Tween 80 on Production of Lipase by Yarrowia Yeast Strains

Lipase is one of the most commonly used biocatalysts in the food, pharmaceutical and cosmetic industries, and can be produced by Yarrowia lipolytica yeast. Despite the intensive studies of lipase from Yarrowia, there are still many open questions regarding the enzyme secretion process, especially by new isolates of this genus as well as the effect of substrates or surfactants, or both on the production of lipase. This research focused on the effect of olive oil and surfactant Tween 80 including the optimisation of the concentration of these compounds on the production of lipase by some novel Yarrowia isolates. Moreover, the optimal environmental parameters (pH, temperature) of crude enzyme synthetised by Yarrowia strains were determined. All investigated strains were able to produce lipase in both intracellular and extracellular fractions. The extracellular lipase activities were higher than the intracellular ones (Y. divulgata Y.02062 and Yarrowia lipolytica 854/4 147 U/L, 80 U/L and 474 U/L, 122 U/L, respectively). In the case of extracellular lipase, supplementing olive oil and Tween 80 enhanced significantly the synthesis and secretion of the enzyme. The lipase activity can even be enhanced by 20 times higher from 25 U/L to 474 U/L in the case of Yarrowia lipolytica 854/4 strain. In the case of intracellular, supplementation of Tween 80 generally reduces lipase activity except for the Y. lipolytica 1/4 strain, which was affected by two times the increase. The optimised concentration of olive oil and Tween 80 were determined for Y. divulgata Y.02062, Y. divulgata 5257, Y. lipolytica 1/4, and Yarrowia lipolytica 854/4 strains as 1.6% olive oil and 0.09% Tween 80, 1.6% olive oil and 0.06% Tween 80, 1.4% olive oil and 0.09% Tween 80 as well as 1.6% olive oil and 0.065% Tween 80, respectively. The optimum pH and temperature of crude lipases (intra and extracellular) synthetised by the tested Yarrowia lipolytica and Y. divulgata yeast strains were found to be pH 7.2 and 37 °C, respectively. Our results confirmed that the new isolate Y. divulgata is a very promising species for further development for industrial use as Y. lipolytica.