Soluble microbial products from the white-rot fungus Phanerochaete chrysosporium as the bioflocculant for municipal wastewater treatment

Soluble microbial products (SMP), a type of polymers released from microbial metabolism and decay, show great potential for wastewater treatment as bioflocculants; however, biogenic flocculant utilization is currently limited to bacterial SMP. In this study, SMP produced by Phanerochaete chrysosporium BKMF-1767 (SMP-P) was investigated to determine the application potential of fungal SMP. SMP-P exhibited high flocculation activity in kaolin suspension at a dosage range of 0.67-0.84 mg/L with Ca2+ assistance, comparable to that of commercial polyacrylamide. The high molecular weight polysaccharides (2.0 x 10(6)-4.7 x 10(7) Da) in SMP-P, which enabled flocculation via the bridging mechanism and served as the dominant active constituent, were composed of glucose and arabinose at a molar ratio of 1: 0.03, with (1 -> 4, 6)-linked glucose as the main backbone and a small proportion of branched structures. They contained hydroxyl and carboxyl, effective functional groups for the flocculation process, and displayed parallel self-orientation behavior in water. Efficient chemical oxygen demand removal was achieved during municipal wastewater treatment using SMP-P as the bioflocculant. This study demonstrates the feasibility of utilizing fugal SMP as bioflocculants and provides guidance for their practical application. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

The study shows that SMP produced by fungi has great potential as an efficient bioflocculant in wastewater treatment; SMP-P contains high molecular weight polysaccharides as the main active component, demonstrating good flocculation effects; Using SMP-P as a bioflocculant achieved effective removal of chemical oxygen demand in municipal wastewater treatment.