Magnetic responsive Thermomyces lanuginosus lipase for biodiesel synthesis

The low cost lipase derived from Thermomyces lanugionous was chosen to conjugate with Fe₃O₄ nanoparitcles as a magnetic responsive lipase (MRL) biocatalyst. The structure of MRL was observed by atomic force microscopy (AFM). The Fourier transform infrared (FTIR) spectroscopy analysis confirmed the lipase conjugated to Fe₃O₄ nanoparticles. Optimized conditions for the process of biodiesel production by MRL were investigated by the response surface methodology (RSM) and the Box-Behnken design (BBD). The optimized conditions for biodiesel production by MRL were as follows. The molar ratio of methanol to oil was 4.0, water content was 1.5 % as oil weight, the dosage of MRL to oil was 9.0 % (W/W) under 41 °C for 28 h. Under the optimized conditions, the yield of FAMEs by MRL reached 82.20 %. Further experiments showed that the MRL could be used 10 cycles and the yield of FAMEs decreased slightly by 10.97 %. These results indicated that Fe₃O₄ nanoparticle carrier could efficiently improve the FAMEs synthesis and enhance the MRL stabilization and reusability in the biodiesel production.