Optimization of microbial oils production from kitchen garbage by response surface methodology

To reuse kitchen garbage for microbial oils, increase the liquid yield, and reduce the production cost, response surface methodology based on Box-Behnken design was employed to identify the optimum conditions for microbial oils production from kitchen garbage by the Geotrichum robustum G9 strain. Experimental results showed that the theoretical maximum lipid yield of 9.89 g/l was obtained with the following optimum conditions: time at 7.55 days, pH at 6.16, and temperature at 28 °C, when the lipid yield could reach 20 kg per ton of kitchen garbage. Analysis results on fatty acids composition and relative content by gas chromatography and mass spectrometry showed that the lipid in strain G9 cultured by kitchen garbage was mainly composed of 16-carbon and 18-carbon fatty acids. Such compositional features were similar to plant oil, the widely used feedstock for biodiesel at present. Kitchen garbage could be considered as ideal substrate for the G. robustum G9 strain for biodiesel production. The utilization...