不同氮源对红曲霉菌产红曲色素的影响

THE EFFECTS OF DIFFERENT NITROGEN SOURCES ON PRODUCTION OF MONASCUS PIGMENT OF MONASCUS SP.

本文比较了四种氮源——甘氨酸、硝酸铵、谷氨酸钠、赖氨酸单盐酸盐对红曲霉菌的细胞生长,发酵过程的pH,红曲色素的产生以及红曲色素的类型组成的影响。结果表明,除赖氨酸单盐酸盐不适于红曲霉生长外,其它三种氨源对菌体干重的影响基本一致。发酸过程中以谷氨酸钠、赖氨酸单盐酸盐为氮源,pH值保持稳定,而甘氨酸、硝酸盐为氮源,发酵后期pH显著升高。红曲色素分胞外色素和胞内色素两种,但大部门为胞内色素。甘氨酸、硝酸铵的胞内色素由红色素和黄色素组成,纯度高,而谷氨酸钠的胞内色素除含有红、黄色素外,还包括许多介于其间的杂色素,纯度低,分辨率差。就甘氨酸、硝酸铵两种氮源来说,以后者为氮源,其红曲色素的色价较高,且其中的黄色素占有较大的比例。故作者认为,如果拟利用红曲霉生产黄色素和红色素为目的,选用硝酸铵为发酵氮源较为合适。

The effects of four nitrogen sources, namely aminoacetic acid (AAA), ammonium nitrate (AN), sodium glatamic acid (SGA)and lysine mono hydrocholoride (LMHC)on mold growth, pH, production and composition of Monascus pigment of Monascus anka have been compared. It was found that the effects of AAA, AN and SGA on mold growth were similar, only LMHC was unfa- vorable for the growth of Monascus anka. pH of broth hardly ever changed during whole fermenta- tion when SGA and LMHC were added as N sources, on the other hand, it became more alkaline in late fermentation when N sources were AAA of AN. Results showed that two kinds of monascus pig- ment, namely entracellular pigment and intracellular pigment were formed by Monascus anka, the later was the majority. Intracellular pigment was composed of red and yellow pigments, however the low purity of monascus pigment was obtained because the monascus pigment contained a lot of other pigment except red and yellow pigment when SGA was N source. Compared AAA with AN, AN was better than AAA as a N source because the pigment value of AN was higher than that of AAA, and yellow pigment took more propotion. It was suggested that AN should be chosen as N source in sub- merged culture of Monascus anka.