Chrysochromulina sp.: A proposed lipid standard for the algal biofuel industry and its application to diverse taxa for screening lipid content

a r t i c l e i n f o Background: The production of algal-derived oil has been recognized as an expanding new industry. Algal oil recovery and quality are impacted by both biological (algal cell type, growth physiology) and technical (recovery and extraction methodologies) constraints. Unfortunately, and unlike other well-established food and oil commodities , presently no universal reference standard exists for use in the algal oil industry. Results: A laboratory-optimized strain of Chrysochromulina sp. is proposed as a natural matrix reference standard for algal fatty acid analysis. The alga is amenable to this purpose because: (a) as a soft-bodied organism, it is susceptible to many disruption and fatty acid extraction techniques; (b) it has a high fatty acid content (~40% dry weight); (c) the growth response and lipid profiles of this organism are highly reproducible; (d) unlike many algae that have limited fatty acid distributions, Chrysochromulina sp. cells contain a broad representation of both saturated and unsaturated fatty acids ranging from C:14 to C:22. As a proof of concept, Chrysochromulina sp. was used as a reference standard for comparing 20 taxonomically diverse algal cultures, grown under identical physiological conditions and analyzed for fatty acid content using a micro-GC/MS analytical technique. Conclusions: Expanding efforts in both commercial and research facilities will require the screening and monitoring of candidate algal strains for lipid synthesis. Universal adoption of a reference standard will provide a common platform to compare the fatty acid compositions of different algal strains grown under diverse environmental conditions and subjected to different oil recovery methods. A reproducibly generated natural matrix standard will have two distinct advantages: (a) as a reproducibly generated standard, it can supplant reference products that vary markedly among suppliers; and (b) the use of a natural matrix standard will help in the identification and elimination of errors in lipid extraction, derivatization and analysis. Industries that produce complex biological commodities (e.g., food, fuel, cosmetics) routinely compare their products to a standard reference material (SRM) to ensure that product quality is within trade specifications. Such products comprise complex macro-molecular matrices (e.g., thick-walled vascular plants or algae) that present nontrivial challenges in quantitation. To compensate, analytical chemists have adopted a type of SRM called a natural matrix standard. The publication of natural matrix standards for food products [1] is among the long-term projects of the National Institute of Standards and Technology (NIST) and the Association of Official …