A comparison of lipid content metrics using six species from the genus Halamphora (Bacillariophyta)

ABSTRACT

The potential for algal-derived lipid products has been well documented and, therefore, has garnered considerable research attention over the last 30 years. Although promising, many hurdles remain in strain selection, optimization and enhancement for commercial production of these products. As this field moves away from the coarse screening efforts that characterized early research and into focused investigations of strain evolution, comparative genetics and genetic engineering, measures of lipid accumulation that are directly comparable and biologically relevant will become increasingly important. Presented here is a comparison of lipid content from six species from the diatom genus Halamphora, H. cf. borealis, H. coffeaeformis, H. oligotraphenta, H. pertusa, H. subturgida and H. turgida, utilizing four lipid reporting methods. Methods examined include percent dry weight and milligrams per liter, as well as newly proposed metrics of lipid per cellular volume and lipids per cell per day. The results demonstrate that the method chosen has a dramatic effect on the conclusions drawn concerning promising strains. Furthermore, commonly used metrics may be inappropriate for interspecific comparisons due to confounding effects outside cellular lipid accumulation. The newly proposed methods offer a biologically relevant alternative to the commonly reported lipids as a percent of dry weight.

KEYWORDS:

• Diatom
• Halamphora
• algae
• lipid measures
• biofuels

Acknowledgments

This research was funded in part by a Seed Grant for Innovation from the University of Colorado Boulder.

Disclosure statement

No potential conflict of interest was reported by the authors.