The recovery of microalgae by means of coagulation-flocculation is efficient, simple and low operating costs. The addition of coagulants makes it possible to destabilize the microalgae surface loads and recover their biomass. Chemical coagulants can contaminate the environment and negatively affect human health. Thus, the exploration of natural coagulants, such as Moringa oleifera and Guazuma ulmifolia, are innovative. Thus, this study aimed to evaluate the efficiency of biomass separation from the microalgae Scenedesmus obliquuos by means of coagulation-flocculation. M. oleifera and G. ulmifolia were used in order to optimize the variables dose, pH and settling time, through a central composite rotational design, which presented recovery efficiencies above 80.0% and 60.0%, respectively. In relation to M. oleifera, optimum regions were obtained for biomass recovery at both pH 4.0 with a dose of 40.0 mg L⁻¹ and pH 9.0 with a dose of 80.0 mg L⁻¹, both in 30 min of settling times. For G. ulmifolia, an optimum dose of 30.0 mg L⁻¹ at pH 4.0 with a 3 min settling time demonstrated that this new coagulant for microalgae recovery has potential for application. Thus, these natural coagulants are promising and can be used in coagulation-flocculation to recover biomass from Scenedesmus obliquuos and, thus, minimize the use of synthetic or metallic products.

通过凝结-絮凝的方式回收微藻是有效，简单且运行成本低的。凝结剂的加入可能使微藻表面负荷不稳定并回收其生物量。化学混凝剂会污染环境并对人体健康产生负面影响。因此，探索天然凝结剂，例如辣木和Guazuma ulmifolia，是创新的。因此，本研究旨在评估通过絮凝-絮凝法从斜藻微藻分离生物质的效率。油橄榄和G. ulmifolia为了通过中央复合旋转设计优化变量剂量，pH和沉降时间，使用了该复合设计，其回收率分别高于80.0％和60.0％。关于油橄榄，在沉降时间30分钟内，在pH 4.0和剂量分别为40.0 mg L ^-1和pH 9.0和剂量为80.0 mg L ^{-1的条件下}均获得了最佳的生物量回收区。对于小叶青霉菌，pH 4.0的最佳剂量30.0 mg L ^-1，沉降时间为3分钟，表明这种用于微藻回收的新型混凝剂具有应用潜力。因此，这些天然凝结剂很有前途，可用于凝结絮凝以回收斜生场景生物质。 因此，尽量减少使用合成或金属产品。