Pyrolysis GC–MS as a novel analysis technique to determine the biochemical composition of microalgae

Abstract

The biochemical composition of microalgae is a major factor in the feasibility of microalgae biofuel systems. Currently full compositional analysis entails tedious, costly and time consuming analysis methods. In the current research, an attempt has been made to use Analytical Pyrolysis Gas Chromatography Mass Spectrometry (Py–GC–MS) to determine the biochemical composition of microalgae. By identifying pyrolysis marker compounds of each main biochemical component of microalgae, the composition of algae samples could be estimated. This was aided by performing Py–GC–MS of a model protein, carbohydrate and lipid. Indole was shown to be a decomposition product from the protein fraction and its levels were consistent with the changing protein content. The lipid content of the microalgae could be estimated from the presence of alkanes and the carbohydrate fraction by the presence of 1,2-cyclopentanedione, 3-methyl-. A total of 26 different microalgae and cyanobacteria strains were investigated for their protein, carbohydrate and lipid levels using established analysis techniques. The biochemical compositions are compared to the results from the novel technique using Py–GC–MS and are shown to correspond well; R2 values were found to be 0.6–0.9. The results suggest that Py–GC–MS can be used as a rapid test for studying levels and changes in biochemical composition of different algae using one fast technique with minimal sample preparation.