黒カビ糖化アミラーゼ生産におけるpreferential synthesisの生理学的解明とその多段連続培養への応用 : (第2報)Preferential synthesisの要因について

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As has already been reported^<1,7)>, glucamylase-producing activity (e) of Aspergillus niger U20-2-5 is negatively correlated with the specific growth rate (μ), which can be controlled by adenine concentration in the growth medium as well as in replacement media. Induction of glucamylase with sorbitol as the gratuitous carbon source is effected most remarkably by maltose ; this can proceed either in growing or in nongrowing (maximum stationary) phase of culture (I). Practically no glucose effect is observed in induction as well as in deinduction experiments. An adenine analogue, 8-aza-adenine, inhibits strongly (ca.75% inhibition the preferential glucamylase synthesis by maturated nongrowing mycelia. The results together with (I) seems to indicate that, in the mycelia whose growth has been restricted by adenine deficiency, RNA and related substances actively turn over in favor of the formation of m-RNA specific for glucamylase synthesis. Action of 8-aza-adenine added together with adenine to the growth medium is antagonized strongly by adenine, thus the action is not percieved until the maximum level of growth is attained. After adenine is almost used up, the action of the analogue becomes remarkable to inhibit glucamylase formation and to bring about lysis due presumably to lethal synthesis. Eight-aza-adenine has no effect on the respiratory activity of mycelia. Though guanine cannot be the substitute of adenine as the growth factor, it has adenine-sparing action as odserved in growth experiments ; a significant part of labeled guanine is taken up by the mycelia, in which it is shown to be converted mostly to GMP. Guanine has the stimulating action upon glucamylase synthesis in growing as well as in nongrowing (maximum stationary) phase of culture. Guanine antagonized the inhibitory effect of 8-aza-adenine on glucamylase formation ; also its excess seems to antagonize the growth effect of adenine. Optimum pH for glucamylase production investigated by replacement culture method using McIlvaine buffer lies in the vicinity of 3 ; mycelia hervested from a young culture (pH 4.2) showed apparently higher pH optimum (4.4) in short period (24 hr) experiments, but it shifted to pH 3 in the course of time. The above results seem to provide some important physiological basis for conducting multi-stage continuous culture dealing with preferential synthesis.
社団法人日本生物工学会の論文
1966-05-25

黒カビ糖化アミラーゼ生産におけるpreferential synthesisの生理学的解明とその多段連続培養への応用 : (第2報)Preferential synthesisの要因について

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