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Screening, Identification and some cultural characteristics of ALA(δ-aminolevulinic acid)-producing photosynthetic bacteria were carried out for the optimal production of ALA, one of the bioherbicides. Among photosynthetic bacteria isolated from soil, marsh, pond, etc., KK-10 was the best producer of ALA and identified to be Rhodobacter capsulatus belonging to a typical group of nonsulfur purple bacteria. By addition of 15 mM LA (levulinic acid), an inhibitor of ALA dehydrase in cyclic tetrapyrrole biosynthesis, into culture broth at middle log phase of cell growths, ALA production was considerably increased to about 20-fold (28 ㎎/ℓ). The combined supplementation of glycine and succinate, each with a concentration of 30 mM also enhanced production of ALA and activity of ALA synthase to about 50-fold (73 ㎎/ℓ) and 2-fold, respectively. The isolated strain was able to produce upto 80 ㎎/ℓ under the cultural condition optimized by addition 15 mM LA into the synthetic medium at four different points starting middle log phase.
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