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Micro‐Raman spectroscopy of algae: Composition analysis and fluorescence background behavior
Author(s) -
Huang Y.Y.,
Beal C.M.,
Cai W.W.,
Ruoff R.S.,
Terentjev E.M.
Publication year - 2010
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.22617
Subject(s) - raman spectroscopy , chlorella sorokiniana , fluorescence , algae , pigment , raman scattering , composition (language) , analytical chemistry (journal) , chemistry , carotenoid , chlorella , fluorescence spectroscopy , botany , biology , food science , chromatography , optics , physics , linguistics , philosophy , organic chemistry
Abstract Preliminary feasibility studies were performed using Stokes Raman scattering for compositional analysis of algae. Two algal species, Chlorella sorokiniana (UTEX #1230) and Neochloris oleoabundans (UTEX #1185), were chosen for this study. Both species were considered to be candidates for biofuel production. Raman signals due to storage lipids (specifically triglycerides) were clearly identified in the nitrogen‐starved C. sorokiniana and N. oleoabundans , but not in their healthy counterparts. On the other hand, signals resulting from the carotenoids were found to be present in all of the samples. Composition mapping was conducted in which Raman spectra were acquired from a dense sequence of locations over a small region of interest. The spectra obtained for the mapping images were filtered for the wavelengths of characteristic peaks that correspond to components of interest (i.e., triglyceride or carotenoid). The locations of the components of interest could be identified by the high intensity areas in the composition maps. Finally, the time evolution of fluorescence background was observed while acquiring Raman signals from the algae. The time dependence of fluorescence background is characterized by a general power law decay interrupted by sudden high intensity fluorescence events. The decreasing trend is likely a result of photo‐bleaching of cell pigments due to prolonged intense laser exposure, while the sudden high intensity fluorescence events are not understood. Biotechnol. Bioeng. 2010;105: 889–898. © 2009 Wiley Periodicals, Inc.