Characterization and Production of Extracellular Polysaccharides (EPS) by Bacillus Pseudomycoides U10

Abstract

We aimed to determine the effect of Luria-Bertani (LB) medium, nutrient broth (NB) and tryptic soy broth (TSB), pH, temperature, and incubation time on the production of extracellular polysaccharides (EPS). The effect of glucose, whey and glycerol on bacterial EPS production by Bacillus pseudomycoides U10 was also tested. LB was better than NB and TSB for EPS production. Maximum EPS production was obtained when 1 g/L whey was added to the growth medium. The influence of incubation times (24-96 h), different pH values (6.5, 7.0, 7.5, 8.0 and 9.0) and temperature (25, 30, 37 and 45 • C) were also tested. The optimum pH level was 7.0 and the highest EPS production was observed at 37 • C after 60 h of incubation. Glycerol was not a good carbon source for cell growth and EPS production. The difference in carbohydrate and protein amount was related to the different types of EPS (dissolved and particulate). In general, the uronic acid content in particulate EPS was lower than in dissolved EPS. The maximum uronic acid was obtained from dissolved EPS (16 mg uronic acid/g EPS). According to X-ray diffraction (XRD), thermogravimetric EPS have a poorly crystalline nature and exhibit two-step degradations, corresponding to the weight loss of moisture and/or carboxyl group and the pyrolysis of EPS, without distinctive changes in different media conditions. Small-angle X-ray scattering (SAXS) data indicate the layer thickness of the bacterial EPS is from 12.04 to 14.07 Å for whey and dissolved LB conditions, respectively. It was found that EPS structures changed with whey addition, such as higher d-values, lower weight losses and more filamentous structures which seemed to be related to increasing durability and/or stability.

Energy Generation from Pharmaceutical Residual Water in Microbial Fuel Cells Using Ordered Mesoporous Carbon and Bacillus subtilis as Bioanode

“…Formation of exopolysaccharides during the formation of a biofilm has been reported for B. subtilis and Bacillus pseudomycoides. 20,40,41 Figure 6f) is a high magnification top-view image showing what seems to be bacteria having rod-like shape with a length of less than 1.5 μm, in good agreement with our previous report on bioanodes having a biofilm of B. subtilis. 42 CVs of the anodes with the different carbon catalysts in KOH and PRW electrolytes are shown in Figure S2.…”

Structural Diversity in Early-Stage Biofilm Formation on Microplastics Depends on Environmental Medium and Polymer Properties

“…Samples were subsequently sputter-coated with a two nm-thick platinum layer (208HR sputter coater, Cressington, Watford, UK) and visualized using the SEM. The structural diversity was further compared with SEM images from the literature [12,31,[41][42][43][44][45][46][47][48][49][50][51][52][53]. Additionally, we investigated both incubation media, freshwater and seawater, as a blank for comparison with the samples.…”

“…The differences between seawater and freshwater in the late-stage biofilm structures may relate to different types of EPS and the differences in salinity of the incubation media. Two types of EPS are typically described, which are defined as dissolved and particulate EPS (pEPS, Figure 3 h) [42,43]. For instance, diatoms show different morphological forms of EPS, such as highly crystalline and rigid fibrils (rough) up to highly hydrated and mucilaginous capsules (smooth) [43,44].…”

What are the different styles of calcite precipitation within a hyperalkaline leachate? A sedimentological Anthropocene case study

“…This significant difference is probably due to the lethally high pH at Brook Bottom (12–12.6). Indeed, biomolecules have a range of pKa between 6.5 and 9 (Solmaz et al, 2018), significantly below 12, so at this pH biomolecules are completely dissolved and cannot construct EPS (Jones et al, 2015). Therefore, the lack of bio‐influence at Brook Bottom is probably to be responsible for the dendritic and shrub fabrics only developing in Consett at a more viable pH (9).…”