Lipids monitoring in Scenedesmus obliquus based on terahertz technology

Abstract

Background Microalgae are considered as a source of low pollution and renewable fuel due to their ability to synthesize an abundance of lipids. Conventional methods for lipid quantification are time-consuming and chemically contaminated, while spectroscopic method combined with mathematical model is much more attractive due to its ability of qualitative and quantitative analysis of material composition, in this sense, terahertz technology provides not only timely and non-destructive testing without chemical pollution, but also provides information on the functional group vibration mode and structure of the measured components. Therefore, terahertz technology is utilized in our investigation and proposed for microalgae metabolism detection. Results The aim of this study was to use terahertz spectroscopy to observe lipid content in Scenedesmus obliquus (S. obliquus). We collected the THz spectra of S. obliquus which were cultivated under nitrogen stress and terahertz spectroscopy was used to analyze changes in substance components (lipids, proteins, carbohydrates and β-carotene). The PLS algorithm was used to model the terahertz data to distinguish the different lipid content of S. obliquus under nitrogen stress. The correlation coefficient of the prediction results of the lipid characteristic band modeling was above 0.991, and the root mean square error was less than 0.132. It indicated that terahertz technology can be used to discriminate S. obliquus cells under different nitrogen stress effectively. The correlation between the terahertz characteristic peak (9.3 THz) and the total lipid content determined by gravimetry reaches 0.960. The final results were compared with the commonly used spectroscopic methods for lipid observation (Raman spectroscopy). Conclusions In this article, we demonstrated the effectiveness of terahertz spectroscopy to monitor changes in microalgae lipid content under nitrogen stress. Terahertz spectroscopy is more suitable for industrial production or ordinary laboratories which require intermediate result with low-frequency screening. When quantifying microalgae lipids, the constraint of terahertz spectroscopy is far less than that of Raman spectroscopy, and it is easier for operator to accurately quantify microalgae lipid. In addition, it is still in early stage for the study of microalgae using terahertz spectroscopy technology, there is still much potential for us to explore.

An Update on the Chemical Constituents and Biological Properties of Selected Species of an Underpinned Genus of Red Algae: Chondrus

“…In the near future, it is suggested to consider employing nondestructive approaches, including surface-enhanced Raman spectroscopy, hyperspectral imaging, near-infrared spectroscopy, terahertz spectroscopy (consisted of electromagnetic waves of 30 µm to 3 mm wavelength range), and fluorescence spectroscopy for evaluating compounds from Chondrus spp. [144,145]. Furthermore, extractions should be focused on the chemical composition of both wild and cultivated Chondrus species.…”

Review of Bioplastics Characterisation by Terahertz Techniques in the View of Ensuring a Circular Economy

“…THz technology was utilised for the investigation of microalgae metabolism detection, considering lipid quantification under nitrogen stress [173]. THz spectra of S. obliquus were collected and analysed to determine the composition, especially the characteristic peak at 9.3 THz was used to determine the lipid content (Figure 11).…”

Hydration Dynamics in Biological Membranes: Emerging Applications of Terahertz Spectroscopy

“…110 However, applications of the THz toolbox based on lipid detection are scarce at present. 111 This is possibly due to limited insights into molecular factors that dictate the microstructure and dynamics of membrane interfacial water, which would be needed for effective deconvolution of THz patterns obtained from complex biological membranes. Both basic and translational advances in this context are expected to depend on technological breakthroughs related to the adaptation of THz spectroscopy to a wide range of biomembrane samples and the integration of THz generation and detection methodologies into complementary experimental, modeling, and theoretical approaches.…”

“…In addition, THz approaches have been successfully utilized toward sensitive detection of biomolecules and pathogenic microorganisms . However, applications of the THz toolbox based on lipid detection are scarce at present . This is possibly due to limited insights into molecular factors that dictate the microstructure and dynamics of membrane interfacial water, which would be needed for effective deconvolution of THz patterns obtained from complex biological membranes.…”