Laboratoire des Procédés Biologiques, Génie Enzymatique et Microbien, UPRES-EA 1026, Polytech'Lille/IUT A, Université Lille Nord de France, Avenue Paul Langevin, 59655 Villeneuve d'Ascq Cedex, France.
Bioresour Technol. 2012 Dec;126:1-6. doi: 10.1016/j.biortech.2012.09.019. Epub 2012 Sep 14.
The influence of power dissipation and volumetric oxygen transfer coefficient k(L)a on Bacillus subtilis productivity of lipopeptides surfactin and fengycin was studied in shake flasks in view of scaling-up of this fermentation process. The experiments performed with different flask sizes, relative filling volumes, and shaking frequencies confirmed clearly that lipopeptide production changed in function of power dissipation, via interfacial gas-liquid contact surface and oxygen supply. It was demonstrated that k(L)a is the key parameter controlling the productivity and the selectivity of the bioreaction. Varying the oxygen transfer conditions, the synthesis could be oriented to mixed production or to surfactin mono-production. The fraction of surfactin towards total lipopeptides produced and the maximal surfactin production both increased with k(L)a increase (surfactin concentration about 2 g L(-1) at k(L)a=0.04-0.08 s(-1)), while the maximal fengycin production (fengycin concentration about 0.3 g L(-1)) was obtained at moderate oxygen supply (k(L)a=0.01 s(-1)).
从发酵过程放大的角度，在摇瓶中研究了功率耗散和体积氧传递系数 k(L)a 对枯草芽孢杆菌脂肽表面活性剂和丰原素生产力的影响。通过使用不同的摇瓶大小、相对填充体积和摇床频率进行实验，清楚地证实了脂肽生产随功率耗散而变化，通过气液界面接触面积和氧气供应来改变。结果表明，k(L)a 是控制生物反应生产力和选择性的关键参数。通过改变氧传递条件，可以将合成导向混合生产或表面活性剂单生产。产生的脂肽中表面活性剂的比例和最大表面活性剂产量都随 k(L)a 的增加而增加（k(L)a=0.04-0.08 s(-1)时表面活性剂浓度约为 2 g L(-1)），而在中等氧气供应下（k(L)a=0.01 s(-1)）可获得最大丰原素产量（丰原素浓度约为 0.3 g L(-1)）。
