This study evaluated how light spectrum, salinity, and glucose level affect Spirulina morphology, using response surface methodology (RSM). A full factorial experiment was conducted including three light conditions with different predominant spectral characteristics (“white”: 100% white; “red”: 80% red, 15% blue, and 5% green; and “yellow”: 80% yellow, 15% blue, and 5% green), four NaCl concentrations (0, 5, 15, 30 g/L), and four glucose levels (0, 1.5, 2, 2.5 g/L). Light spectrum conditions and salinity had significant effects on the filament length, spiral diameter, and screw pitch length. Glucose only had a significant effect in terms of the spiral diameter. The maximum filament length (1274 μm; under 30 g/L NaCl and 2.5 g/L glucose), spiral diameter (47 μm; under 1 g/L NaCl and 2 g/L glucose), and screw pitch length (112 μm; under 1 g/L NaCl and 2 g/L glucose) were attained under yellow light. In line with the simulation, more compacted filaments, that is, with a greater diameter (41 μm) and shorter screw pitches (78 μm), are observed under “red” light (4 g/L NaCl and 2.5 g/L glucose). Because longer but compact filaments are desirable for easier harvesting, we recommend a light spectrum that is predominantly red with a NaCl concentration of 5.8 g/L deprived of glucose, for the cost-effective harvesting of Spirulina biomass.

中文翻译：

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光谱、盐度和葡萄糖水平对螺旋藻形态的影响

本研究使用响应面法 (RSM)评估了光谱、盐度和葡萄糖水平如何影响螺旋藻形态。进行了全面析因实验，包括具有不同主要光谱特征的三种光条件（“白色”：100% 白色；“红色”：80% 红色、15% 蓝色和 5% 绿色；“黄色”：80% 黄色、 15% 蓝色和 5% 绿色）、四种 NaCl 浓度（0、5、15、30 g/L）和四种葡萄糖水平（0、1.5、2、2.5 g/L）。光谱条件和盐度对丝长度、螺旋直径和螺距长度有显着影响。葡萄糖仅对螺旋直径有显着影响。最大丝长度（1274 μm；30 g/L NaCl 和 2.5 g/L 葡萄糖下）、螺旋直径（47 μm；1 g/L NaCl 和 2 g/L 葡萄糖下）和螺距长度（112 μm；112 μm；2.5 g/L 葡萄糖下）。在 1 g/L NaCl 和 2 g/L 葡萄糖下）在黄光下获得。与模拟一致，在“红”光（4 g/L 氯化钠和 2.5 g/L 葡萄糖）下观察到更紧凑的细丝，即具有更大的直径 (41 μm) 和更短的螺距 (78 μm) 。由于较长但紧凑的丝状体更容易收获，因此我们建议使用主要为红色、氯化钠浓度为 5.8 g/L、不含葡萄糖的光谱，以经济高效地收获螺旋藻生物质。