Analysis and glycosyl composition of the exopolysaccharide isolated from the floc‐forming wastewater bacterium Thauera sp. MZ1T

Abstract

Conditions were developed for the reproducible production, isolation and characterization of a novel microbial extracellular polysaccharide believed to be involved in transient viscous bulking at an industrial wastewater treatment plant. The exopolysaccharide was extracted from cell-free culture supernatants of Thauera sp. strain MZ1T grown on a minimal medium with succinate. The purified polymer was found to be approximately 260 kDa in size by gel-permeation chromatography. The GC-MS analysis of the alditol acetate and per-O-trimethylsilyl methyl glycoside derivatives revealed that the exopolysaccharide was composed of four monosaccharides including: rhamnose, galacturonic acid, N-acetylglucosamine and N-acetylfucosamine. Glucose, which also appeared at low levels, is most likely from a co-eluting glucan. The FTIR and NMR spectroscopic analyses further revealed the presence of esterified component groups on the polymer. These results represent the first published description of a polysaccharide from a member of the genus Thauera, and lay the foundation for a deeper understanding of the factors potentially involved in zoogloeal cluster formation and viscous bulking.

Comparative genomics analyses on EPS biosynthesis genes required for floc formation of Zoogloea resiniphila and other activated sludge bacteria

“…The EPS of Thauera aminoaromatica Mzlt was composed of four monosaccharides including rhamnose, galacturonic acid, N-acetylglucosamine and N-acetylfucosamine (Allen et al, 2004). The latter two aminosugars, N-acetylglucosamine and N-acetylfucosamine, have also been previously identified in an axenic Zoogloea bacterium (Tezuka, 1973).…”

“…With the capacity of EPS synthesis and flocformation, PAOs could be enriched in activated sludge for phosphorus recovery in EBPR process. Previously EPS synthesis and floc formation have been described in Nitrosomonas and Thauera strains (Stehr et al, 1995;Allen et al, 2004). It could also be inferred that other desired bacteria of activated sludge, including Dechloromonas, Azoarcus, Nitrosomonas and Nitrosospira species, could form flocs, thereby being enriched in AS process and contributing to sludge formation.…”

“…There are two acetate permeases (ActP) and the acetate kinase encoded in the genome of Zoogloea, which may be the reason why this bacterium could utilize acetate as efficiently as Thauera did (Allen et al, 2004). Some activated sludge bacteria could uptake the volatile fatty acids (VFAs) such as acetate and propionate and store available VFAs as polyhydroxyalkanoates (PHAs) during the anaerobic period (Mino et al, 1998).…”

“…The samples were hydrolyzed in 1 M methanolic-chloride acid (methanolicHCl) overnight at 80 C. The samples were cooled to room temperature and then the methanolic-HCl was removed by dry nitrogen flush. The TMS (trimethylsilyl group) methyl derivatives were generated and were analyzed by gas chromatography/mass spectrometry (GC/MS) (Agilent Model 6890N/5973inert chromatograph outfitted with a DB-5MS capillary column) as previously described (Allen et al, 2004).…”

The biophysics of a critical phenomenon: colonization and sedimentation of the photosynthetic bacteria Rubrivivax gelatinosus

“…Optical assay for sugars As the bacterial exopolysaccharides are composed of monosaccharides including rhamnose, galacturonic acid, N-acetylglucosamine and Nacetylfucosamine (Allen et al 2004) and glucose at low levels, colorimetric method for carbohydrates was applied. The soluble carbohydrates content of the biofilm was efficiently extracted by 95% ethanol in 1:1 (v:v) ratio with bacterial culture at room temperature.…”