Métodos de extração de biofloculantes: uma revisão

Abstract

With the need to develop more sustainable processes that are less aggressive to the environment and human health, the production of bioflocculants and their application in water treatment systems have been widely studied. The present study aimed to evaluate the main methods of extracting bioflocculants from culture media, gathering their mechanisms, operational parameters, as well as their economic and ecological potential, in order to assist future research on the development of industrial processes and obtaining new bioflocculants. This work qualifies as basic and descriptive research, of a qualitative nature, configured as an integrative review of scientific literature. The results indicate that physical methods and mild saline or aqueous extractions preserve the structural integrity of macromolecules. In contrast, alkaline treatments and EDTA, despite higher crude yields, cause cell lysis and contamination. It is concluded that the viability of the techniques resides in the balance of their operational properties. Mild methods present the advantage of recovering extracellular polymers of high purity and functional activity, but bring as a disadvantage lower crude yields or slow kinetics. On the other hand, harsh methods offer the advantage of high nominal yields in tightly bound fractions, but have the severe disadvantage of inducing cell lysis, degrading the macromolecular structure, and generating secondary chemical wastes. Given these trade-offs, physical routes assisted by ultrasound or microwaves, along with saline extractions, consolidate as the most promising since they reconcile structural integrity, energy efficiency, and Green Chemistry principles. Finally, subsequent investigations should focus on life cycle assessments (LCA) and economic viability on an industrial scale, as well as developing standardized protocols for utilizing local agro-industrial wastes and native plants from the Cerrado biome.