Efficient Production of Active Form Recombinant Cassava Hydroxynitrile Lyase Using Escherichia coli in Low-Temperature Culture

Hydroxynitrile lyase (MeHNL, EC 4.1.2.39) is a useful enzyme for production of optically active cyanohydrin compounds. Production of MeHNL can be increased by substituting rare codons of the natural sequence of cassava (
Manihot esculenta
) MeHNL. However, most of the MeHNL produced by this method was in an insoluble form in
Escherichia coli
expression system. In order to increase the productivity of active form of MeHNL, the effects of cultivation temperature were investigated. When the cultivation temperature was reduced, the cell yield and the ratio of soluble MeHNL increased significantly. The enzyme activity and yield at low-temperature cultures (17�C) were 850 times higher than those obtained at the optimum growth temperature of 37�C. The rate of MeHNL production in the present study was calculated as 3,000 U/h. Low-temperature cultivation is very effective in improving the productivity of the active form of MeHNL and has more potential for large-scale production of MeHNL for optically active cyanohydrin production.