Current developments in high‐throughput analysis for microalgae cellular contents

Abstract

Microalgae have emerged as one of the most promising feedstocks for biofuels and bio-based chemical production. However, due to the lack of effective tools enabling rapid and high-throughput analysis of the content of microalgae biomass, the efficiency of screening and identification of microalgae with desired functional components from the natural environment is usually quite low. Moreover, the real-time monitoring of the production of target components from microalgae is also difficult. Recently, research efforts focusing on overcoming this limitation have started. In this review, the recent development of high-throughput methods for analyzing microalgae cellular contents is summarized. The future prospects and impacts of these detection methods in microalgae-related processing and industries are also addressed.

Imaging of Lipids in Microalgae with Coherent Anti-Stokes Raman Scattering Microscopy

“…In the attempt to identify algal strains and environmental conditions that promote the accumulation of large amounts of intracellular lipids to be harvested as biofuels and nutraceuticals, a growing body of studies involving batch (Breuer et al, 2012;Griffiths et al, 2012) or high-throughput (Lee et al, 2013) lipid screening techniques has appeared. For instance, nitrogen-limited conditions have repeatedly been shown to promote significant accumulation of neutral lipids for a wide collection of algal strains (Breuer et al, 2012;Griffiths et al, 2012;Erickson and Jimenez, 2013), and elevated PUFA levels have been reported at low light exposure (Thompson et al, 1990).…”

Monitoring of Microalgal Processes

“…Other measurement principles include NMR spectroscopy, FC, GC-MS, high-performance liquid chromatography (HPLC), pyrolysis, and dielectric spectroscopy. A survey of currently used standard offline methods can be found in the publication of Technical Standards Committee of the Algal Biomass Organization [9] and a review on high-throughput analysis methods [8]. A short overview of the advantages and disadvantages of current advanced methods for lipid (triacylglyceride) determination in microalgae is given in [166].…”

“…Measurement of fluorescence in the form of 2D fluorometry, spectroscopy in the visible and infrared range, and Raman spectroscopy can be used for estimation of pigment, lipid, and biomass concentration [8,24,35,[171][172][173]. FC could also be adapted for online monitoring of cell size and shape distributions, culture composition, and identification of invaders and of biomass composition, and some attempts in this direction have already been made [117].…”

“…In recent years, monitoring methods that can be used in microalgal processes have been increasingly sought as these processes pose specific challenges that will require both adaptation of existing monitoring methods and development of new approaches. So far, the research efforts observed in the literature have concentrated on high-throughput methods that can process samples drawn from the cultivation rapidly and with high frequency but in the classic offline mode [7][8][9]. For process automation, however, online, noninvasive monitoring methods minimizing the measurement delay and employing in situ sensors are of high value.…”

“…The real-time monitoring of cellular components is very difficult but high-throughput methods, carried out either serially with high speed or in parallel, on samples drawn from the cultivation in offline mode but with the highest possible degree of automation, aim to close the gap to real-time analysis. Measurement principles employed so far include optical methods as fluorescence spectrometry and flow cytometry (FC), Fourier transform infrared (FTIR), NIR, and Raman spectrometry, colorimetric detection by image analysis, submicroscale gas chromatography-mass spectrometry (GC-MS), nuclear magnetic resonance (NMR) and dielectrophoresis, as shown in recent reviews [7,8] and in a publication of the Algae Biomass Organization (ABO) Technical Standard Committee [9]. Attempts to adapt some of these high-throughput methods to online use have been made for Raman spectroscopy [35] and colorimetry [36] but, on the whole, this task is difficult.…”