A novel non-aqueous-plate method for easily and intuitively detecting the transesterification activity of lipase for enzymatic biodiesel.

The transesterification activity of lipase is a key factor to enzymatic biodiesel preparation. Herein, a novel non-aqueous-plate method was created to easily and intuitively detect the transesterification activity of lipase. The non-aqueous plate is a heated, emulsified, and cooled down mixture of animal fat with/without plant oil, tert-butanol, and methanol, in which solid-semitransparent support and dye are added to make it more stable and observable at room temperature. It was verified by gas chromatography that the transparent halo displayed on the non-aqueous plate was majorly transesterification with slight hydrolysis based on the aqueous content of the added microliter-scaled enzyme sample. In addition, the functional relationship between the diameter of the transparent halo and the enzyme activity was measured and utilized as a quantitative measurement of the transesterification activity of lipase. Compared with the traditional liquid transesterification method, the non-aqueous-plate method is intuitive and simple for qualitative and quantitative detection of lipase transesterification activity. It demands less lipase and could be applied in screening the target enzyme out on one plate or several, which is great labor- and time-saving. The as-created promising method could be utilized as a standard to intuitively evaluate the transesterification activity of various lipases for enzymatic biodiesel.