Simultaneous thermogravimetry and differential thermal analysis for comparing burning characteristics between oleaginous and non-oleaginous microorganisms

Simultaneous thermogravimetry (TG) and differential thermal analysis (DTA) were applied to the studies of microorganisms, including Escherichia coli JM109, Rhodococcus opacus B-4, Saccharomyces cerevisiae, and Mortierella alpina IFO32281. M. alpina IFO32281 is known as an oleaginous fungus, while the other microorganisms examined are non-oleaginous species. The mass-difference baseline method, where the DTA curve for a small-mass sample was used as the baseline for a large-mass sample, was employed to quantify the endothermic and exothermic peaks on the DTA curves. A marked difference in heat energy between the oleaginous fungus and the non-oleaginous microorganisms was detected in the temperature range from 280 to 360 °C. The heat evolved from M. alpina IFO32281 in this temperature range was approximately 5.5 J/g, which was 3.3- to 11-fold greater than those detected from the non-oleaginous microorganisms.