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2 Acta Biochimica Polonica

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Adhesive and hydrophobic properties of the selected LAB isolated from gastrointestinal tract of farming animals

100%

Grajek K. , Sip A. , Foksowicz-Flaczyk J. , Dobrowolska A. , Wita A.

Acta Biochimica Polonica

2016

tom 63

nr 2

311-314

The aim of this study was to determine the degree of adhesion and hydrophobicity of some strains of lactic acid bacteria (LAB) with proven antagonistic properties against pathogenic bacteria. Studies were performed using-LAB strains isolated from the gastrointestinal tract of calves and piglets. These strains exhibited an antibacterial activity against pathogenic strains of Clostridium perfringens and Escherichia coli. Cell adhesiveness was examined in relation to the porcine and bovine mucin. Our analyses had shown that the tested microorganisms demonstrated a degree of adhesion in the range of 32.00-40.00% for strains isolated from calves, and 34.00-40.00% for strains isolated from pigs. The hydrophobicity of tested bacteria was in the range of 31.00%-44.00% for strains isolated from pigs, and 26.00%-42.00% for strains obtained from calves. The best mucin adhesion ability was found for bacterial strains belonging to the Enterococcus genus isolated from calves. Taking into account porcine isolates, the best adhesion was observed for the Leuconostoc bacterial strains. Among tested strains, the highest hydrophobicity, measured in relation to hexadecane, was recorded for the bacterial strains belonging to the Leuconostoc sp. isolated from piglets and a of Lactobacillus sp. bacterial strain isolated from calves.

Group II intron-mediated deletion of lactate dehydrogenase gene in an isolated 1,3-propanediol producer Hafnia alvei AD27

86%

Celińska E. , Drożdżyńska A. , Wita A. , Juzwa W. , Białas W. , Czaczyk K. , Grajek W.

Acta Biochimica Polonica

2017

tom 64

nr 1

123-133

Our previous studies showed that glycerol fermentation by Hafnia alvei AD27 strain was accompanied by formation of high quantities of lactate. The ultimate aim of this work was the elimination of excessive lactate production in the 1,3-propanediol producer cultures. Group II intron-mediated deletion of ldh (lactate dehydrogenase) gene in an environmental isolate of H. alvei AD27 strain was conducted. The effect of the Δldh genotype in H. alvei AD27 strain varied depending on the culture medium applied. Under lower initial glycerol concentration (20 gL-1), lactate and 1,3-propanediol production was fully abolished, and the main carbon flux was directed to ethanol synthesis. On the other hand, at higher initial glycerol concentrations (40 gL-1), 1,3-propanediol and lactate production was recovered in the recombinant strain. The final titers of 1,3-propanediol and ethanol were similar for the recombinant and the WT strains, while the Δldh genotype displayed significantly decreased lactate titer. The by-products profile was altered upon ldh gene deletion, while glycerol utilization and biomass accumulation remained unaltered. As indicated by flow-cytometry analyses, the internal pH was not different for the WT and the recombinant Δldh strains over the culture duration, however, the WT strain was characterized by higher redox potential.