The production of microalgal biomass and its derived products on a large-scale requires the development of sustainable and cost-effective harvesting technologies. Biomass recovery is the primary step in the downstream processing of microalgae and it is a costly operation because microalgal cultures are stable hydrophilic colloidal suspensions. Bio-flocculation has been proposed as a low-cost technology that can be employed to dewater microalgal cultures thus making secondary harvesting methods like filtration and centrifugation less energy-intensive. This review provides an overview of increasing applications of plant-based biopolymers in microalgal biomass harvesting on laboratory and pilot-scale culture volumes. The structure, preparation, and flocculation activity of natural and chemically cationized plant biopolymers are presented. Recent studies demonstrating microalgal biomass recovery have been summarized discussing the advantages and limitations of plant-based biopolymers as emerging bio-flocculants. Future perspectives on biopolymers with special attention to studies reported on nutrient medium recycling, environmental impact assessment and techno-economic analysis of plant-based bio-flocculants facilitated bio-flocculation have been discussed.

大规模生产微藻生物质及其衍生产品需要开发可持续且具有成本效益的收获技术。生物量回收是微藻下游加工的主要步骤，并且是昂贵的操作，因为微藻培养物是稳定的亲水性胶体悬浮液。已经提出了生物絮凝作为一种低成本技术，该技术可用于对微藻培养物进行脱水，从而使诸如过滤和离心分离的二次收获方法的能源消耗更少。这篇综述概述了在实验室和中试规模的培养量下，基于植物的生物聚合物在微藻类生物质收获中日益增加的应用。介绍了天然和化学阳离子化的植物生物聚合物的结构，制备和絮凝活性。总结了微藻生物质回收的最新研究，讨论了作为新兴生物絮凝剂的基于植物的生物聚合物的优势和局限性。讨论了生物聚合物的未来前景，特别关注了有关营养介质循环利用，环境影响评估以及基于植物的生物絮凝剂促进生物絮凝的技术经济分析方面的研究报告。