Viscosity is a nonnegligible factor in the waste activated sludge fermentation: Taking hyaluronan as an example.

The waste activated sludge (WAS) exhibits typical viscoelasticity due to the presence of viscous and gelling organics in extracellular polymeric substances (EPS). However, the positive role of reducing viscosity in WAS fermentation by degrading viscous polysaccharides has been historically overlooked. This work demonstrates the occurrence of viscous hyaluronan-like polysaccharides in the WAS for the first time.

Elucidating the complex hydrolysis and conversion network of xanthan-like extracellular heteropolysaccharides in waste activated sludge fermentation.

The hydrolysis of structural extracellular polymeric substances (St-EPS) is considered a major limiting step in the anaerobic fermentation of waste activated sludge (WAS). However, the degradation of heteropolysaccharides, characterized by complex monomers of uronic acids and neutral saccharides in St-EPS, has rarely been reported. In this study, microbial-produced xanthan-like heteropolysaccharides, characterized by a blue filamentary film, were identified.

[The fluorescence characteristics of dissolved organic matter (DOM) in the seagrass ecosystem from Hainan by fluorescence excitation-emission matrix spectroscopy].

The fluorescence characteristics of dissolved organic matter (DOM) were determined in the seagrass ecosystem collected in Xincun Bay of Hainan Island in late January, 2013, using fluorescence excitation-emission matrix spectroscopy (EEMs). EEMs spectra showed 2 types of fluorescence signals in DOM samples, three hurnic-like fluorescence peaks and two protein-like fluorescence peaks, respectively. The former included UVC peak A (Ex/Em: 230/430 nm), UVA peak C (Ex/Em: 350/440 nm), and UVA peak M (Ex/Em: 300/380-400 nm), while the latter included tryptophan-like peaks R (Ex/Em: 230/355 - 375 nm) and N (Ex/Em: 280-300/365-380 nm).