Effect of redox potential on the growth of Yarrowia lipolytica and the biosynthesis and activity of heterologous hydroperoxide lyase

The aim of this study was to investigate the effect of redox potential (Eh) on the growth of the yeast Yarrowia lipolytica in both oxidizing (Eh = +350 mV) and reducing (Eh = −150 mV) media and its effect on the expression and activity of hydroperoxide lyase (HPL). HPL activity was assayed in media with Eh values ranging from −250 to +720 mV. In order to change the Eh value of the media, reducing agents including dithiotreitol (1 g/L) and hydrogen (4%) as well as oxidants such as potassium ferricyanide (1 g/L) and oxygen (100%), were used. The experimental findings showed that oxidizing conditions, with Eh of +350 mV, were favorable for the growth of the yeast, whereas reducing conditions, with Eh values of −150 mV, resulted in a higher expression of HPL. In addition, the results showed that the enzymatic activity of the purified HPL was enhanced in the presence of 0.5 mM dithiotreitol but decreased with 1 mM potassium ferricyanide and bubbling O2. However, HPL activity increased 1.5 times in the presence of 4% hydrogen with an Eh value of −170 mV.