Biotech Updates

Cost-effective Quantification of Ethanol Yields in Switchgrass by Near-Infrared Reflectance Spectroscopy (NIRS)

February 25, 2011
(full access to journal article may require subscription or payment) http://www.springerlink.com/content/n783w00264390l36/
http://www.ars.usda.gov/research/publications/publications.htm?seq_no_115=251127

Process monitoring and analysis of lignocellulosic-biomass conversion to biofuels often require long, costly and "destructive" procedures of biomass compositional analysis. The compositional analysis (which includes cellulose, hemicelluloses and lignin fractions) are often used (1) to estimate the ethanol yields of the biomass, or (2) to assess effectiveness of biomass conversion processes.

Researchers from the Agricultural Research Service of the United States Department of Agriculture (USDA-ARS) report the use of "Near-Infrared Reflectance Spectroscopy" (NIRS), as an inexpensive, less-complex and less-extensive method for analysis of biomass samples for quantitative evaluation of biomass-to-biofuel processes. NIRS is based on the "differential absorbance and reflectance of light at specific wave lengths" when the sample is subjected to near-infared light.

The (absorbance/reflectance) response of the sample to near-infrared light can be correlated (or "calibrated") with the properties of the biomass, including carbohydrate/lignin content or potential ethanol yield. In the study, the researchers developed NIRS calibration curves "for switchgrass biomass, that can be used to estimate over 20 components including cell wall and soluble sugars and also ethanol production as measured using a laboratory conversion and fermentation procedure".

Using NIRS-derived data for the biomass, they were able to demonstrate that switchgrass cultivars and experimental strains "differed significantly", in terms of biomass composition, and ethanol yields. The researchers also mentioned that "conventional analyses costs for this study would have exceeded $100,000 but with NIRS the costs of the analyses were approximately $3000 or about $10 per sample." The results of the study are published in the journal, Bioenergy Research (URL above).

Related information on Near Infra-Red Spectrospectroscopy (NIRS)
http://www.fq.uh.cu/dpto/qf/docencia/pregrado/estruc_2/curso_07_08/ir_07_08/IRcercano.pdf
http://plantsci.missouri.edu/roberts/NIRmonograph.pdf.