Carlozzi Pietro, Ena Alba, Carnevale Silvia
Consiglio Nazionale delle Ricerche, Istituto per lo Studio degli Ecosistemi, Sezione di Firenze, Polo Scientifico, Via Madonna del Piano, 50019 Sesto F.no, Firenze, Italy.
Biotechnol Prog. 2005 Mar-Apr;21(2):416-22. doi: 10.1021/bp049665l.
The rheological behavior of an Arthrospira culture was studied from low to high biomass concentration. Two tubular undulating row photobioreactors (TURP-5r and TURP-10r), with a very short light path of 1.0 cm, were used during batch growth. In TURP-5r, the biomass concentration increased to 14.5 g(dw) L(-1), and alterations of the physical properties and hydrodynamic behavior occurred as a result. In the past, the rheological characteristics of photosynthetic-microbe cultures were rarely investigated because of the low biomass concentration attained in the systems. Developing closed photobioreactor technologies, the optimum biomass concentration rises and the viscosity, the generalized Reynolds number (N'(Re)), and the power required for culture recycling are also subject to alteration. Starting from a biomass concentration of 4.1 g(dw) L(-1), the Arthrospira culture already exhibits the characteristics of a non-Newtonian fluid. As a result of culture recycling from 2.0 to 20.5 g(dw) L(-1) and an available power of 1.67 W row(-1), we demonstrated that N'(Re) is reduced from 6265 to 1148. Our experimental results showed that N'(Re) of 2345 can be reached only at a cell concentration below 11.1 g(dw) L(-1), while at a cell concentration below 4.1 g(dw) L(-1) N'(Re) = 4080 was reached. The power consumption (P(c)) for culture recycling increased noticeably when the cell concentration rose; the highest P(c) increase attained was from 2.0 to 4.1 g(dw) L(-1). This is the range within which the Arthrospira culture changes from a Newtonian to a non-Newtonian fluid.
从低生物量浓度到高生物量浓度研究了螺旋藻培养物的流变行为。在分批培养过程中，使用了两个光程非常短（1.0厘米）的管状起伏排式光生物反应器（TURP-5r和TURP-10r）。在TURP-5r中，生物量浓度增加到14.5克（干重）/升，结果导致物理性质和流体动力学行为发生改变。过去，由于系统中达到的生物量浓度较低，很少研究光合微生物培养物的流变特性。随着封闭式光生物反应器技术的发展，最佳生物量浓度升高，粘度、广义雷诺数（N'(Re)）以及培养物循环所需的功率也会发生变化。从生物量浓度4.1克（干重）/升开始，螺旋藻培养物就已经表现出非牛顿流体的特性。由于培养物在2.0至20.5克（干重）/升之间循环以及有1.67瓦/排的可用功率，我们证明N'(Re)从6265降至1148。我们的实验结果表明，只有在细胞浓度低于11.1克（干重）/升时才能达到2345的N'(Re)，而在细胞浓度低于4.1克（干重）/升时达到N'(Re) = 4080。当细胞浓度升高时，培养物循环的功耗（P(c)）显著增加；P(c)增加最高的是在2.0至4.1克（干重）/升之间。这是螺旋藻培养物从牛顿流体转变为非牛顿流体的范围。
