Rapid determination of bulk microalgal biochemical composition by Fourier-Transform Infrared spectroscopy

Abstract

Analysis of bulk biochemical composition is a key in fundamental and applied studies of microalgae and is essential to understanding responses to different cultivation scenarios. Traditional biochemical methods for the quantification of lipids, carbohydrates and proteins are often time-consuming, often involve hazardous reagents, require significant amounts of biomass and are highly dependent on practitioner proficiency. This study presents a rapid and non-destructive method, utilising Fourier-Transform Infrared (FTIR) spectroscopy for the simultaneous determination of lipid, protein and carbohydrate content in microalgal biomass. A simple univariate regression was applied to sets of reference microalgal spectra of known composition and recognised IR peak integrals. A robust single-species model was constructed, with coefficients of determination r(2)>0.95, high predictive accuracy and relative errors below 5%. The applicability of this methodology is demonstrated by monitoring the time-resolved changes in biochemical composition of the marine alga Nannochloropsis sp. grown to nitrogen starvation.

Nitrate Reductase Knockout Uncouples Nitrate Transport from Nitrate Assimilation and Drives Repartitioning of Carbon Flux in a Model Pennate Diatom

“…In 10 rescued NR knockouts, YFP expression was also induced when the cells were switched from NH 4 + to NO 3 2 media (Supplemental Figure 3). FTIR spectroscopy, previously calibrated using biochemical measurements (Levering et al, 2016;Mayers et al, 2013;Stehfest Figure 3A). During a 7-d time course experiment, three NR-KO lines (#9, 14, and 15) and the wild type were initially grown in NH 4 + media and then transferred into NO 3 2 -amended media and sampled periodically.…”

“…FTIR spectrophotometry provides for the simultaneous measurement of functional groups and chemical bonds in cells to allow identification of their biochemical composition (D'Souza et al, 2008;Mayers et al, 2013). We monitored macromolecular groups, lipids, carbohydrates, and proteins, over a 7-d time series using an IR21 spectrophotometer (Shimadzu).…”

Monitoring of Microalgal Processes

“…In the MIR range, an attenuated total reflection (ATR) device was used for simultaneous determination of lipid, protein, and carbohydrate content in powdered freeze-dried microalgal biomass [195]. Effects of sample treatment were studied and conditions necessary to obtain accurate, rapid, and robust estimation of cellular lipid content were ascertained for freeze-dried samples of N. oculata [196].…”

Rapid method for simultaneous discrimination of microalgae and determination on biochemical composition based on vibrational spectroscopy

“…Другая крупная спектральная вариация наблюдалась в окне 3, которое соответствует белкам. Здесь преобладали вибрации структурных белковых групп Амид I и Амид II (Mayers et al, 2013). Значительную полосу при 1651 cм -1 мы отнесли к Амид I из-за режима растяжения С-О белка, а при 1548 cм -1 -к Амид II за счет поглощения изгибной вибрации N-Н-полосы.…”

“…pyrenedosa (85,64) и E. gracilis (34,06) отражают более высокое поглощение S. obliquus по сравнению с другими видами микроводорослей, что непосредственно отражает более высокую концентрацию и интенсивность компонента Амид А в клетках этого вида. Группы Амид A, Амид I и Амид II считаются наиболее надежным регионом для количественного определения содержания белков в биологических системах (Mayers et al, 2013 Плотность белков, определенная по ИК-ПФ-спектрам, отражает линейную зависимость от содержания белка в биомассе, рассчитанную методу М.М. Брэдфорда (Bradford, 1976), тем самым подтверждая результаты, полученные из ИК-ПФ (табл.…”