A review of thermochemical conversion of microalgae

Microalgae are very effective microorganisms for CO2 capturing and a promising source of lipids for biodiesel as well as other interesting compounds. Many different ways of exploitation of these organisms are being tested. This work presents a review of the state of the art of the research and development of thermochemical conversion of microalgae with a special focus on pyrolysis and hydrothermal liquefaction. Aspects related to the type of reactors, the products obtained and the analytical applications are covered. The actual reaction scheme of pyrolysis of microalgae is extremely complex because of the formation of over hundreds of intermediate products. Various kinetic models reported in the literature and in a previous study with experimental validations are presented in this review to provide the current status of the study.

Thermogravimetry and Py–GC/MS techniques as fast qualitative methods for comparing the biochemical composition of Nannochloropsis oculata samples obtained under different culture conditions

Microalgae have many applications, such as biodiesel production or food supplement. Depending on the application, the optimization of certain fractions of the biochemical composition (proteins, carbohydrates and lipids) is required. Therefore, samples obtained in different culture conditions must be analyzed in order to compare the content of such fractions. Nevertheless, traditional methods necessitate lengthy analytical procedures with prolonged sample turn-around times. Results of the biochemical composition of Nannochloropsis oculata samples with different protein, carbohydrate and lipid contents obtained by conventional analytical methods have been compared to those obtained by thermogravimetry (TGA) and a Pyroprobe device connected to a gas chromatograph with mass spectrometer detector (Py–GC/MS), showing a clear correlation. These results suggest a potential applicability of these techniques as fast and easy methods to qualitatively compare the biochemical composition of microalgal samples.