Myxococcus xanthus DK1622 enhance sludge dewatering performance

The removal of bound water remains one of the most significant challenges in sludge reduction. As classic predatory microorganisms, myxobacteria, exhibit broad-spectrum predatory activity against various organisms. However, it remains unclear whether myxobacteria can prey on sludge microorganisms and subsequently induce bound water release. This study demonstrates that the application of myxobacteria at different concentrations significantly reduced water content, total suspended solids (TSS), and volatile suspended solids (VSS) in sludge. Notably, the addition of Myxococcus xanthus DK1622 at 200 mg/L achieved a 0.85 % reduction in water content. At this optimal concentration, TSS and VSS decreased by up to 4.58 g/L and 2.29 g/L, respectively. The predation process induced significant changes in extracellular polymeric substances (EPS), with protein and polysaccharide concentrations increasing by 2.3-fold and 1.2-fold, respectively. These alterations were attributed to cellular material leakage during predation, which in turn contributed to EPS accumulation. Furthermore, the disruption of microbial aggregates via predatory activity facilitated the release of bound water from the sludge. These findings provide valuable insights for potential applications of myxobacteria in biological sludge dewatering processes.