Sugar composition and FT-IR analysis of exopolysaccharides produced by microbial isolates from paper mill slime deposits

Abstract

Thirty exopolysaccharides (EPS) produced by bacteria isolated from biofilms or slimelayers from different paper and board mills in Finland, France and Spain were subjected to size exclusion chromatography and sugar compositional analysis. High performance size exclusion chromatography (HPSEC) analysis revealed that some samples were composed of several molecular weight populations. These samples were fractionated by size exclusion chromatography and pooled accordingly. Principal components analysis (PCA) of the sugar compositions of the different pools indicated the presence of glucans and mannans caused by insufficient removal of the carbon or nitrogen source (yeast extract) from the bacteria growth medium leading to an overestimation of the glucose and mannose level in the sample, respectively. From the point of view of slime problems the EPS populations are the most important for multivariate analysis. Four groups of EPSs have been recognized by PCA analysis: a group of EPSs produced by Enterobacter and related genera similar to the regularly reported colanic acid; a group of Methylobacterium EPSs having high galactose and pyruvate levels and two groups that showed less dense clusters produced by Bacillus and related genera, showing high mannose and/or glucose levels and Klebsiella EPSs that showed galactose with rhamnose as major characteristic sugar moieties. Fourier transform infrared spectroscopy (FT-IR) of the same samples followed by discriminant partial least squares regression (DPLS) and linear discriminant analysis (LDA) showed that, when used with a well-defined training set, FT-IR could be used clustering instead of time-consuming sugar composition analysis. The Enterobacter and Methylobacetrium EPS groups could be recognized clearly. However the fact that this could hardly be done for the other two groups in the dataset indicates the importance of a larger and well-defined training or calibration set. The potential to use FT-IR, as a tool for pattern recognition and clustering with respect to EPS structures produced by micro organisms isolated from a paper mill environment is discussed.

Characterization of Extracellular Polymeric Substances from Acidophilic Microbial Biofilms

“…Consequently, given the diversity in the glycosyl compositions of EPS produced by various microorganisms, it is difficult to predict or justify the specific composition for any given EPS. Similar to the glycosyl composition of EPS produced by microorganisms isolated from paper mill slimes (38,39), galactose, glucose, rhamnose, and mannose are present in great abundance in the AMD biofilms. Although xylose has been found in some bacterial EPS, such as Paenibacillus and Idiomarina species EPS (2,25), it is not a common sugar residue associated with EPS.…”

Enzymatic approaches in paper industry for pulp refining and biofilm control

“…Verhoef (2005) showed the presence of the EPSs colanic acid in several different paper mills from Spain and Finland. Colanic acid is commonly known to be produced by several members of the Enterobacteriaceae family.…”

“…Due to this, most enzymes acting on EPSs have to be isolated from 3 major sources: endogenously from EPSs synthesising microorganism, exogenously from a wide range of other prokaryotic and eukaryotic microorganism or from bacteriophage particles or phage induced bacterial lysates. Enzymes are usually highly specific (Simoes 2010, Verhoef 2005.…”

Viability study of biofilm-former strains from paper industry by flow cytometry with application to kinetic models

“…One is located in Finland and the other in Spain. These strains were selected because their high capability of producing EPS (Verhoef et al, 2005) Experimental set-up Pre-inocula were prepared using shake flasks at 37ºC and 150 rpm in a medium containing glucose (20 g·L Each bioreactor (Sartorius model Biostat B-plus of 1L) was seeded with the volume of inoculum calculated previously. The medium employed for cultivation was the same as the one used for inoculum preparation.…”

“…These studies provide information on the importance of certain microorganism strains in the early stages of biofilm formation (Kolari et al, 2003) and on the amount and type of polysaccharides that they produce (Verhoef et al, 2005). Thus specific control programs can be developed e.g.…”