【摘要】 初选藤仓赤霉菌（Gibberella fujikuroi）农大17菌株为赤霉素A₄、A₇（GA₄、GA₇）的生产菌,该菌株GA₄₊₇的积累量,除与营养条件有关外,温度和pH是极为重要的因子,随着发酵温度从28℃上升至32℃,GA₄₊₇的产量由21μg/ml增至81μg/ml,GA₃由702μg/ml降至328μg/ml。pH回调至中性,GA₄₊₇的产量由75μg/ml增至180μg/ml,GA₃由322μg/ml降至211μg/ml。此外,设法延长发酵周期也是增加GA₄₊₇的一个因素。综合上述条件,即发酵过程中,发酵液的pH由48h前的4回调并维持在6.7左右,温度由28℃上调并控制在32℃,摇瓶培养12天,GA₄₊₇的产量达890μg/ml,20—600L发酵罐发酵240h,GA₄₊₇产量达680μg/ml左右。GA₄₊₇浓度的测定亦作了简化处理,发酵液不经提取,可直接用硅胶板G薄层层析（TLC）后进行荧光比色,产品测定宜采用高效液相色谱法（HPLC）。按照上述条件培养的农大17菌株,产生GA₃、GA₇和GA₄的比例为23.131:16.105:31.258,GA₄高于有关报道。更多还原

【Abstract】 A strain of Gibber ella fujikuroi (ND 17) was selected for production of GA4+7. In addition to the components of broth, fermentation temperature and pH were the most important factors which affect the yield of GA4+7 of this strain. With the increase of fermentation temperature (from 28t to 32℃) the liter for GA4+7 increased (from 21μg/ml to 81μg/ml). The titer for GA3 decreased (from 702μg/ml to 328μg/ml). If pH was adjusted nearneuter, the titer for GA4+7 increased (from 75μg/ml to 180μg/ml) and for GA3 decreased (from 322μg/ml to 211μg/ml). Moreover, the elongation of the fermentation time was another factor to increase the yield of GA4+7. Consequently, during the fermentation of GA4+7, the pH value of the broth should be adjusted from -4 to 6.7 after 48hrs and maintained the level, and the temperature was kept at 28℃ before adjustment of pH and at 32℃ thereafter. The yield of GA4+7 in shake flasks achieved 890μg/ml at 12 days and reached about 680μg/ml in 600L fermentor. Assay of the concentration of GA4+7 in broth was simplified, the example of the broth treated by TLC using pre-coated silica gel G plates was analysis by spectrofluorimetry. The product of GA4+7 was assayed by HPLC. The rotio of GA3, GA7 and GA4 in broth fermented by this strain was 23.131:16.105:31.258, the titer of GA4 was higher than that of being reported.更多还原