螺旋霉素的生物合成Ⅳ.发酵过程中ATP与SPM生物合成的关系

BIOSYNTHESIS OF SPIRAMYCIN IV. CORRELATION BETWEEN ATP CONTENT AND SPIRAMYCIN BIOSYNTHESIS

螺旋霉素的生物合成受碳、氮分解代谢物的阻遏和终点产物的抑制。螺旋霉素发酵对工艺条件很敏感,影响发酵过程的因素很多,且错综复杂。对发酵控制可资借鉴的参数极少。为此,本文研究了发酵过程中ATP的变化与螺旋霉素生物合成的关系,从中发现,过程ATP水平过高,对SPM生物合成不利,因基质主要用于初级代谢。另外,基础配方加油的批号比不加油的批号的ATP水平低,糖耗小,SPM单位平均增长42％。ATP含量高会抑制脂肪的代谢。发酵液的溶磷会影响ATP的含量,从而影响发酵单位。但发酵后期加入少量磷酸盐有利于SPM的合成,静息细胞系统中证明磷酸盐的作用在于减轻葡萄糖和NH_4^+的阻遏和SPM的反馈抑制,还促进SPM中三个糖的合成与连接。

Spiramycin biosynthesis is liable to be subjected to carbon and nitrogen cataboltte repression and end product inhibition. Spiramycin fermentation is highly sensitive to its operation conditions, since there are numerous variables which affect the fermentation process. However, only a few of them can be monitored and controlled during the fermentation. Thus,the correlations between ATP and spiramyc-ia synthesis and other variables in the course of fermentation were studied. It was found that high level of ATP in the culture broth was unfavorable to spiramycin biosynthesis. Besides, compared with the control, ATP level was lower, glucose consume rate was less, while average spiramycin potency was enhanced by 42% in the fermentation batches with vegetable oil supplement. Dissolved phosporous compound cotent could affect the generation of ATP and thereby the biosynthesis of spiramycin. Nev ertheless, the supplement of KH2PO4 at late stage of the fermentation had a favorable effect on spiramycin production. It was elucidated in resting cell system that phosphate played the role of alleviating the glucose and NH4 repression and end product inhibition of spiramyctn biosynthesis, and promoting the biosynthesis and glycosidation of the sugar moieties precusors to macrolide.