Mechanism of morphological development of mycelia and its application on production of microbial product

对高山被孢霉菌丝球的内部结构和菌丝生长速率、顶端形成率、顶端伸长率和分枝形成率等形态参数进行了研究。荧光显微镜下观察异硫氰酸荧光素(FITC)和尼罗红标记后菌丝球的内部结构。颗粒呈椭圆形，内部结构呈甜甜圈状，内部有凹陷，从颗粒内部结构的三维图像判断清晰可见。图像分析显示菌球边缘有脂肪酸生成，与菌丝体密集部位相对应。空腔比根据荧光强度的面积计算，在50-L发酵罐中保持在20%，但最终增加到35%。菌丝颗粒体积与空腔比平行，在25种不同碳氮浓度组合下，利用流通室测量了菌丝形态参数，发现它们不受C/N比的影响，而受培养基中碳浓度的影响。在较低的碳浓度(5g/L)下，菌丝生长和菌尖形成的比速率保持不变。当碳浓度低于15g/L时，一根尖端的伸长速率为60(μm/TIP/h)，分枝形成率与碳浓度无关。菌丝伸长速率与菌丝生长速率成正比，菌丝生长速率与菌丝生长速率呈线性关系，说明菌丝伸长速率与菌丝生长速率呈指数关系。菌丝伸长速率低于60(μm/TIP/h)和比菌丝生长速率低于0.83h^~(-1)~(-1)时，各菌丝单元的分枝形成率保持不变。

The intrastructure of mycelial pellets of Mortierella alpina and the morphological parameters, such as hyphal growth rate, tip formation rate, tip extension rate and branch formation rate of Mortierella alpina have been investigated in this research. The intrastructure of mycelial pellets were visualized following labeling with fluorescein isothiocyanate (FITC) and Nile red using fluorescence microscopy. The pellet was an ellipse shape, but its intrastructure was shaped as doughnut and a cave was present inside, which was clear by judging 3-D image of intrastructure of pellet. Using image analysis, the fatty acid production was shown on the verge of pellet, which was corresponded on the place of dense mycelia. The cavity ratio was calculated from area based on the fluorescent intensity and remained at 20% in a 50-L fermentor but finally increased to 35%. Mycelial pellet volume was paralleled to the cavity ratio.Using a flow-through chamber under 25 different combinations of carbon and nitrogen concentrations, morphological parameters were measured and found that they were influenced not by C/N ratio but by carbon concentration in medium. Specific rates of hyphal growth and tip formation remained at constant at lower carbon concentration of 5 g/l, respectively. Tip extension rate from one tip was 60 (μm/tip/h) in a carbon concentration below 15 g/l, and branching formation rate was independent upon carbon concentration. Tip extension rate was a function of specific hyphal growth rate, and the specific hyphal growth rate was linearly proportional to the specific tip formation rate, which demonstrated that tip extension rate was exponentially proportional to the specific tip formation rate. Branch formation rate per hyphal element remained unchanged even at lower tip extension rate than 60 (μm/tip/h) and at lower specific hyphal growth rate than 0.83 h^<-1>, respectively.