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Shimotori, K., University of Tsukuba, Tsukuba, Japan, shimotori.koichi.gp@u.tsukuba.ac.jp
Watanabe, K., National Institute for Environmental Studies, Tsukuba, Japan, watanabe.keiji@nies.go.jp
Hama, T., University of Tsukuba, Tsukuba, Japan, thama@biol.tsukuba.ac.jp

RELATIONSHIP BETWEEN FLUORESCENCE CHARACTERISTICS AND MOLECULAR WEIGHT OF FLUORESCENT DISSOLVED ORGANIC MATTER PRODUCED BY BACTERIA

Four bacterial strains transformed organic substrates to fluorescent dissolved organic matter (FDOM) in culture media. The fluorescence characteristics of the FDOM were analyzed by means of excitation-emission matrix (EEM) spectroscopy. Simultaneously, the molecular weight of the FDOM was analyzed by means of high-pressure size-exclusion chromatography (HPSEC) with fluorescence and absorbance detection. EEM peaks corresponding to humic-like fluorescence were detected in all culture media. Additionally, EEM peaks in the region generally attributed to UV humic-like fluorescence were detected in two of four culture media. The FDOM fractions having UV humic-like fluorescence had lower molecular weights than the fractions having visible humic-like fluorescence. These results suggest that the fluorescence characteristics of the bacteria-derived FDOM were related to its molecular weight. The HPSEC results for the bacterial culture media with absorbance detection at 260 and 280 nm revealed that the bacterial strains transformed organic substrates to lower-molecular-weight components that included aromatic carbon content. The mismatch between the eluent patterns of the fluorescence and absorbance chromatograms indicates that the fluorescence intensity of bacteria-derived FDOM was related to its chemical composition and structure.

Poster presentation

Session #:SS17
Date: 7/10/2012
Time: 18:00 - 20:00