Production of extracellular polymeric substances from Rhodopseudomonas acidophila in the presence of toxic substances

2005 ◽  
Vol 69 (2) ◽  
pp. 216-222 ◽  
Author(s):  
Guo-Ping Sheng ◽  
Han-Qing Yu ◽  
Zheng-Bo Yue
2001 ◽  
Vol 43 (6) ◽  
pp. 169-175 ◽  
Author(s):  
M. Strathmann ◽  
T. Griebe ◽  
H.-C. Flemming

For investigating the influence of extracellular polymeric substances (EPSs) on biofilm properties, artificial models of defined composition and structure can be very helpful. Different immobilised cell systems can be useful in the fitting of experimental results. Two different types of artificial EPS matrix model were developed earlier. Homogeneous agarose beads (50-500 μm diameter) and porous beads (260 μm mean diameter) containing pores with diameters from 10 to 80 μm (28 μm on average), allowed the embedding of cells, particles and typical EPS matrix components such as proteins and polysaccharides. In this paper, some physico-chemical properties of the artificial EPS matrices were described and compared with results known from natural EPS. The stability of the artificial matrix polymer against solution in the aqueous medium was studied in batch experiments. The water binding and water retaining capabilities of the EPS models were investigated by drying and re-swelling experiments. The simulation of protective effects of the artificial EPS matrix against toxic substances like biocides in comparison to such known protective effects of the EPS of native biofilms were proved by the application of sodium hypochlorite (0.5 mg/l, 30 min) and subsequent microscopic investigation of the cell population after LIVE/DEAD staining (Molecular Probes).


2020 ◽  
Author(s):  
Jonas Chodorski ◽  
Jan Hauth ◽  
Andreas Wirsen ◽  
Roland Ulber

<p>Through their special way of life, biofilms have several advantages over organisms in planktonic growth. By being surface-attached and producing a mass of extracellular polymeric substances (EPS), microorganisms possess inherent self-immobilization, which decreases the expenditure of downstream processing in industrial applications. Furthermore, they are more resilient against environmental stress and toxic substances, such as antibiotics. An important factor here is diffusion, of substrate into the biofilm and metabolites through and out of the biofilm; however, these mechanisms are still poorly understood. By utilizing a specially developed diffusion model and CLSM FRAP microscopy, diffusion constants in the living, fully hydrated biofilm of <em>L. lactis</em> during development can be assessed. With it, heatmaps of diffusional constants and finally a diffusion profile encompassing a true 3D space of the living biofilm in growth can be generated. With those, possible hotspots and changes of diffusion inside the biofilm structure with regard to changing cultivation conditions and the substratum can be identified, thus furthering our understanding of diffusion in biofilms and how they react to their environment.</p> <p>The project is funded by the DFG (UL 170/14-1) and the collaborative research center (SFB) 926 on “microscale morphology of component surfaces” (MICOS).</p>


2020 ◽  
pp. 66-72
Author(s):  
Irina A. Piterskikh ◽  
Svetlana V. Vikhrova ◽  
Nina G. Kovaleva ◽  
Tatyana O. Barynskaya

Certified reference materials (CRM) composed of propyl (11383-2019) and isopropyl (11384-2019) alcohols solutions were created for validation of measurement procedures and control of measurement errors of measurement results of mass concentrations of toxic substances (alcohol) in biological objects (urine, blood) and water. Two ways of establishing the value of the certified characteristic – mass consentration of propanol-1 or propanol-2 have been studied. The results obtained by the preparation procedure and comparison with the standard are the same within the margin of error.


Author(s):  
J. P. F. D'Mello ◽  
Carol M. Duffus ◽  
John H. Duffus
Keyword(s):  

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