TECHNOLOGY FOCUS - BIOTECHNOLOGY - Preferred Method: In producing biofuel, the basic solid catalyst precursor is a metal zincate. Zincate is a precursor of an alkaline earth metal or a divalent transition metal. The precursor is calcium zincate dihydrate. Thermal activation of basic solid catalyst precursor is conducted at 350-800 degrees C. Activation is performed in an inert atmosphere of a noble gas, preferably helium. The activation is performed using a heating rate of 20 degrees C/minute. Thermal activation of basic solid catalyst precursor is at 400 degrees C. The time spent on the activation temperature is 1 hour. Activation is performed in a tube furnace. Transesterification substrates include oils or animal fats or vegetable and a low molecular weight alcohol. Vegetable fats or oils are derived from sunflower and soybean. The low molecular weight alcohol is methanol. Transesterification performed in a completely mixed batch reactor under an atmosphere of nitrogen gas (N2), reflux, magnetic stirring and reaction temperature of 60 degrees C. The reactor is connected to a cooling system to maintain constant volume of alcohol and to allow for monitoring reaction temperature. The reaction temperature of transesterification stage is produced by a silicone bath heated by a hotplate. Reaction conditions are: 1 to 4% by weight of thermally activated precursor at 400 degrees C, methanol:oil molar ratio of 12:1, temperature at 60 degrees C for transesterification; and stirring speed of 1000 revolutions per minute (rpm) for reaction mixture. Preferably, the reaction conditions are: 4% by weight of thermally activated precursor 400 degrees C; methanol:oil molar ratio of 12:1; transesterification reaction temperature of 60 degrees C; and stirring speed of the reaction mixture at 1000 rpm. Filtration of the product after removing the transesterification is carried out through a microfilter. Neutralization of the extracted transesterification product is done by HCl. Settling is performed by adding dichloromethane and the resulting mixture is stirred vigorously. Removing dichloromethane and traces of alcohol ester phase after settling stage is done by heating for 5 hours in a sand bath at 90 degrees C.