Rhizopus属と細菌の連関作用によるフマル酸醗酵からアスパラギン酸への転換醗酵 : (第1報)菌株の選択ならびに転換に対する諸条件

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Fundamental experiments were performed to establish the conversion of fumaric acid fermentation to aspartic acid fermentation by the association of fumaric acid-producing Rhizopus and bacteria having a high aspartase activity.Proteus vulgaris AHU 1144 was selected as the best strain for the conversion from 180 strains of bacteria. Shaking culture was much more effective on the conversion than stationary culture.(NH_4)_2HPO_4 was quite favorable as the ammonia source required for the production of aspartic acid and a molarity ratio of fumaric acid to ammonium ion of 1 : 2 was most efficient. Optimum inoculm size was 2.0×10^9 cells per ml of the medium.An initial pH of 6.5 adjusted with excess CaCO_3 was suitable for the conversion.Ca-fumarate as a substrate was much more desirable than NH_<4->, K_-, or Na-fumarate.When P.vulgaris was cultured with shaking at 32℃ in a medium containing Ca-fumarate (4% as fumaric acid) under favorable conditions, the conversion from fumaric acid to aspartic acid was completed within 24 hr and the aspartic acid yield was more than 90%.Considerably large amounts of malic acid were accumulated in the early phase of incubation, then sharpy decreased.It appeared that an equilibrium heavily inclined to aspartic acid was finally established among aspartic, fumaric, and malic acids.
社団法人日本生物工学会の論文
1972-11-25