Comparison of screening methods for high-throughput determination of oil yields in micro-algal biofuel strains

Abstract

The phenotypic and phylogenetic diversity of micro-algae capable of accumulating triacylglycerols provides a challenge for the accurate determination of biotechnological potential. High-yielding strains are needed to improve economic viability and their compositional information is required for optimizing biodiesel properties. To facilitate a high-throughput screening programme, a very rapid direct-derivatization procedure capable of extracting lyophilized material for GC analysis was compared with a scaled-down Folch-based method. This was carried out on ten micro-algal strains from 6 phyla where the more rapid direct-derivatization approach was found to provide a more reliable measure of yield. The modified Folch-based procedure was found to substantially underestimate oil yield in one Chlorella species (P < 0.01). In terms of fatty acid composition however, the Folch procedure proved to be slightly better in recovering polyunsaturated fatty acids, in six out of the ten strains. Therefore, direct-derivatization is recommended for rapid determination of yields in screening approaches but can provide slightly less compositional accuracy than solvent-based extraction methods.

Unlocking nature’s treasure-chest: screening for oleaginous algae

“…This procedure requires only 1 mg DW (from as little as 2 mL culture) encapsulated in foil with a run-time of 8 min per sample. Therefore, for future screening, this procedure would allow a faster processing time and a significant scale-down of culture volume leading to higher throughput (more so than is possible with GC of directly trans-esterified FA43 or FTIR spectroscopy44). Only the Nile-Red plate assay approach would be faster, but this technique has limitations in accuracy relating to between-species comparison, dye uptake and carotenoid interference25.…”

“…Cyanocobalamin 0.5 μgl −1 , Biotin 0.5 μgl −1 ; Thiamine-HCl 0.1 mgl −1 ) were added after autoclaving. Growth was monitored by dual measurement of in vivo chlorophyll fluorescence and cell turbidity as described previously43. In the primary screen cultures of 100 mL were inoculated from starter cultures and incubated without agitation under a 12 h:12 h L/D (light/dark cycles) regime at 50-80 μmol m −2 sec −1 at 20 °C for 7-14 d, (Innova 44, New Brunswick Scientific, Edison, NJ).…”

From the Ancient Tribes to Modern Societies, Microalgae Evolution from a Simple Food to an Alternative Fuel Source

“…Henry Ford launched a new car that worked with pure bioethanol or blends with gasoline (Mussatto et al, 2010). The country of Brazil developed the ProAlcool project in 1975(Soccol et al, 2005 and currently leads the world in ethanol export potential, even compared to the United States, Japan, and Europe. Brasil also launched another project, OVEG, in 1983 aimed at biodiesel production from vegetable oils.…”

“…Brasil also launched another project, OVEG, in 1983 aimed at biodiesel production from vegetable oils. The success of the bioethanol program was a solution to the 1970s fuel crisis; however, it introduced another crisis related to competition with food sources (Soccol et al, 2005;Mussatto et al, 2010).…”

“…So far, the research team has screened 2700 microalgae strains from culture collections in order to define promising strains for lipid production. The team has published a few papers, mostly dealing with climate change and global warming risks, alternative species for lipid production and strain screening, strain improvement, reviews about biogas production, techno-economic development , and research on biogas production from seaweeds (Allan, 2011;Callaway et al, 2012;Day et al, 2012;Hughes et al, 2012;Roleda et al, 2013;Dave et al, 2013;Slocombe et al, 2013aSlocombe et al, , 2013bVanegas and Bartlett, 2013).…”