Relationship between the cell surface hydrophobicity and survival of bacteria Zymomonas mobilis after exposures to ethanol, freezing or freeze-drying

Abstract

An inverse linear relationship (P < 0.01) was detected between the cell surface hydrophobicity (CSH) and survival of ethanologenic bacteria Zymomonas mobilis 113S exposed to elevated (2.55 M) ethanol concentration. In the same way, viable cell counts of relatively hydrophobic Z. mobilis were less diminished by growing (0.85-3.40 M) ethanol concentrations as compared to more hydrophobic bacteria. Very similar inverse relationships (P < 0.01) were observed between the CSH of intact Z. mobilis and survival of cells subjected to subsequent freeze-drying or freezing/thawing cycles thereby affinity substantially lowered ability of hydrophobic bacteria to survive under adverse environments. Observed relationships were supported by significant correlations between independent analytical data of the carbohydrate content within fractions of lipopolysaccharide and surface proteins extracted from cells of varied hydrophobicity. The results suggest that the CSH could be of value to predict the ability of intact bacteria to endure stress conditions and should be monitored towards lower values during cultivation in order to reduce subsequent unwanted structural and physiological disturbances provoked by multiple stress factors.

Influence of growth conditions on hydrophobicity ofLactobacillus acidophilusandBifidobacterium lactiscells and characteristics by FT-IR spectra

“…For example in cell biomass with CSH from 61.2 to 75.1% the total carbohydrate content decreased from 20.93 to 10.50% DW and the protein content increased from 58.99 to 67.45% DW. Similar relationships were detected for bacteria Z. mobilis 113S and reported previously [13]. Observed…”

Biodegradation of phthalic acid esters by a newly isolated Mycobacterium sp. YC-RL4 and the bioprocess with environmental samples

“…Benzoic acid was metabolized for cell growth by benzoate metabolism pathway biodegradation. Microorganisms with higher CSH were supposed to have potential superiorities in petroleum bioremediation and endurance stress conditions (Plaza et al 2005;Shakirova et al 2008). Zhang et al (2010) reported the biodegradation of beta-cypermethrin (beta-CP) degrading by two Serratia strains and further investigation found that high hydrophobicity of cells could enhance the degradation of beta-CP.…”

A study on cell surface hydrophobicity, growth and metabolism of Zymomonas mobilis influenced by PEG as a pretreatment agent

“…28 Lipopolysaccharides (LPS) form the last outer layer of the cell wall in gram negative proteobacteria 29 and are therefore affected rst when environmental conditions change. Shakirova et al 20 showed a carbohydrate content reduction in LPS fractions of more hydrophobic Z. mobilis cells concomitantly with a proportional decrease of ketodeoxy gluconic acid concentration in corresponding LPS samples. Therefore, it can be concluded that PEG changes the LPS of Z. mobilis, possibly by altering the amounts of LPS constituents.…”

“…16 Several studies have investigated the effect of various environmental conditions and shocking procedures such as freeze-drying, freezing and thawing on the viability and ultra-structure of Z. mobilis. [17][18][19][20] Zikmanis et al 18 studied the effect of different amphiphilic compounds on the hydrophobicity and protein secretion of Z. mobilis. The effect of some surfactants, especially nonionic surfactants of the tween group on Pseudomonas aeruginosa, Escherichia coli, Saccharomyces cerevisiae and Mycobacterium paratuberculosis were examined; the studies mentioned above reected the change of growth and ethanol tolerance of these microorganisms as inuenced by the tested surfactants through the changes of membrane constituents.…”

“…The cell surface properties of bacteria are known to be vital to the survival of an organism, since the various surface constituents organize the contact and interaction of the bacterium with its environment. 20 Thus CSH determination is crucial for understanding the PEG effect on the growth and metabolism of Z. mobilis.…”