• Korean Journal of Food Science and Technology
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• v.26 no.1
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• pp.93-97
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• 1994

A study of physical and chemical characteristics of pigments from Rhodopseudomonas viridis DSM 133 was carried out for development of natural greenish colorant. Through visible absorption scanning, it showed three main absorption peaks at 378, 414 and 677 nm with three minor peaks at 510, 540 and 618nm, and it was shown to be greenish color. These pigments were more stabilized in alkaline solutions than in acid of between pH 6 and 9, and it was shown to be stabilized at the temperature below $40^{\circ}C$. In the presence of light and oxygen, the stability of pigments rapidly degraded, and it became unstable in the presence of metal ion such as $Fe^{3+}$ and $Al^{3+}$. But in the presence of $Cu^{2+}$ were very stable. On the result of TLC analysis, pigments were shown to be composed of four color fractions and main color fractions were F-4 and F-2.

• Environmental Engineering Research
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• v.12 no.4
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• pp.136-147
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• 2007

In an effort to identify possible microbes for seeking bioagents for remediation of herbicide-contaminated soils, seven species of phototrophic nonsulfur bacteria (Rhodobacter capsulatus and sphaeroides, Rhodospirillum rubrum, Rhodopseudomonas acidophila, blastica and viridis, Rhodomicrobium vannielii) were grown in the presence of the herbicide, butachlor, and bacterial growth rates and nitrogen fixation were measured with different carbon sources. Under general conditions, all species showed 17-53% reductions in growth rate following butachlor treatment. Under nitrogen-fixing conditions, Rb. capsulatus and Rs. rubrum showed 1-4% increases in the growth rates and 2-10% increases in nitrogen-fixing abilities, while the other 5 species showed decreases of 17-47% and 17-85%, respectively. The finding that Rp. acidophila, Rp. blastica, Rp. viridis and Rm. vannielii showed stronger inhibitions of nitrogenase activity seems to indicate that species in genera Rhodobacter and Rhodospirillum are less influenced by butachlor than those in Rhodopseudomonas and Rhodomicrobium in terms of nitrogen-fixing ability. Overall, nitrogenase activity was closely correlated with both growth rate and glutamine synthetase activity (representing nitrogen metabolism). When the carbon sources were compared, pyruvate (three carbons) was best for all species in terms of growth rate and nitrogen fixation, with malate (four carbons) showing intermediate values and ribose(five carbons) showing the lowest; these trends did not change in response to butachlor treatment. We verified that each of the 7 species had a plasmid ($12.2{\sim}23.5\;Kb$). We found that all 7 species could use butachlor as a sole carbon source and 3 species were controlled by plasmid-born genes, but it is doubtful whether plasmid-born genes were responsible to nitrogen fixation.