Algal Biomass Constituent Analysis: Method Uncertainties and Investigation of the Underlying Measuring Chemistries

Algal biomass compositional analysis data form the basis
of a large
number of techno-economic process analysis models that are used to
investigate and compare different processes in algal biofuels production.
However, the analytical methods used to generate these data are far
from standardized. This work investigated the applicability of common
methods for rapid chemical analysis of biomass samples with respect
to accuracy and precision. This study measured lipids, protein, carbohydrates,
ash, and moisture of a single algal biomass sample at 3 institutions
by 8 independent researchers over 12 separate workdays. Results show
statistically significant differences in the results from a given
analytical method among laboratories but not between analysts at individual
laboratories, suggesting consistent training is a critical issue for
empirical analytical methods. Significantly different results from
multiple lipid and protein measurements were found to be due to different
measurement chemistries. We identified a set of compositional analysis
procedures that are in best agreement with data obtained by more advanced
analytical procedures. The methods described here and used for the
round robin experiment do not require specialized instrumentation,
and with detailed analytical documentation, the differences between
laboratories can be markedly reduced.