Arthrospira platensis is a cyanobacterium that is of great biotechnological interest, particularly for the food industry, as it possesses a high content of proteins, pigments, lipids and carbohydrates. Cyanobacteria produce extracellular polymeric substances (EPS), which are co-products of secondary metabolism that present thickening or gelling properties. A 3-level factorial design was used to study the combined effect of different nitrate concentrations and photon flux density (PFD) values to evaluate the biomass and EPS production of A. platensis. The best result in terms of biomass production was obtained under condition 6 (2 g L⁻¹ NaNO₃ and 600 μE m⁻² s⁻¹) yielding a concentration of 1.292 g L⁻¹. However, condition 1 (0.25 g L⁻¹ NaNO₃ and 200 μE m⁻² s⁻¹) produced the greatest EPS yield (111 mg g⁻¹), followed by condition 9 (2 g L⁻¹ NaNO₃ and 1000 μE m⁻² s⁻¹). FTIR analyses of EPS samples indicated the presence of carboxylate and sulfate functional groups, and rheological studies of the EPS at 5 and 10 g L⁻¹ revealed a dilute solution behavior.

中文翻译：

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培养条件对节肢动物胞外聚合物（EPS）产生的影响

钝顶螺旋藻是一种蓝细菌，具有很高的生物技术意义，特别是对于食品工业而言，因为它具有高含量的蛋白质，色素，脂质和碳水化合物。蓝细菌会产生细胞外聚合物（EPS），它们是次级代谢的副产物，具有增稠或胶凝特性。使用三级因子设计来研究不同硝酸盐浓度和光子通量密度（PFD）值的组合效应，以评估白僵菌的生物量和EPS产量。在条件6（2 g L ^-1 NaNO ₃和600μEm ^-2  s ^-1）产生的浓度为1.292 g L ^-1。但是，条件1（0.25 g L ^-1 NaNO ₃和200μEm ^-2  s ^-1）产生最大的EPS产量（111 mg g ^-1），随后是条件9（2 g L ^-1 NaNO ₃和1000μE） m ^-2  s ^-1）。EPS样品的FTIR分析表明存在羧酸盐和硫酸盐官能团，并且EPS在5和10 g L ^-1下的流变学研究表明溶液的稀释行为。