Biostat@B发酵罐生产低色素短梗霉多糖的研究

Studies on the Pullulans Polysaccride Produced by Biostat@B Fermentor

所用菌株是从长期保存的出芽短梗霉菌种经复壮、筛选后得到的一株多糖产量相对高、色素水平相对低的菌株,通过摇瓶发酵确定最佳培养条件,并解决了短梗霉发酵的一些问题,例如:菌丝结团,pH下降过快影响多糖的产量等,使其多糖转化率提高了10%~20%,色素含量明显减少,后通过Biostat@B5L发酵罐发酵培养,确定了最适发酵条件,通气量为1.5 vvm,转速为500 rpm,发酵液颜色在乳白到淡黄之间,无需脱色处理,即可得到白色粗糖产品,多糖产量达到35 g/L,转化率达到65%左右,较好的平衡了多糖量和色素量的关系。

Pullulans polysaccride, produced from Aureobasidium pullulans, is a kind of extracellular polysaccride. In the current study, in order to change the permeability of cell membrane and solve the problem of linked group of fungi mycelium, the method adding tween-80 and different Ca2+ resources was established. The utilized strain with relatively high polysaccride yield and low pigment level was obtained after the rejuvenation and riddling of long-preserved Aureobasidium pullulans strain. The transformation ratio of polysaccride was increased by 10% - 20% and the pigment content was greatly reduced. By adopting Biostat@B5L fermentor according to the optimum formula, and find the opti-mum aerate speed is 1.5 vvm, and the rate of circle is 500 rpm and culture temperature is 28?C ±1.5?C, and initial pH is 6.5, so a high conversion rate of 65% (35 g/L polysaccride yield)was obtained from the light colour medium. The fer-menting liquor is between milk white and light yellow, and the white primary product can be gained without decolora-tion step.