| 1. |
- Deraz, Sahar, et al.
(author)
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Capture of bacteriocins directly from non-clarified fermentation broth using macroporous monolithic cryogels with phenyl ligands
- 2007
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In: Enzyme and Microbial Technology. - : Elsevier BV. - 0141-0229. ; 40:4, s. 786-793
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Journal article (peer-reviewed)abstract
- The bacteriocin, sakacin P was produced by the bacteriocin-producing strain Lactobacillus sakei CCUG 42687 at 20 degrees C without pH control. The bacteriocin was captured directly from the fermentation broth using macroporous octyl- and phenyl-monolith columns. The large size of the interconnected macropores (up to 100 mu m) in the macroporous monolith allowed for direct fermentation broth processing with no clarification needed. Screening for optimal bacteriocin binding demonstrated that at pH 6.2 about 80% of the bacteriocin activity could be recovered with a purification factor of 150-160 in the cell-free eluate. Capture of bacteriocins from the fermentation broth using macroporous monoliths in the 96-well plate format presents a promising approach for rapid analytical isolation of bacteriocins from numerous samples.
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| 2. |
- Deraz, Sahar, et al.
(author)
-
Mode of action of acidocin D20079, a bacteriocin produced by the potential probiotic strain, Lactobacillus acidophilus DSM 20079
- 2007
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In: Journal of Industrial Microbiology & Biotechnology. - : Oxford University Press (OUP). - 1367-5435 .- 1476-5535. ; 34:5, s. 373-379
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Journal article (peer-reviewed)abstract
- Lactobacillus acidophilus DSM 20079 is the producer of a novel bacteriocin termed acidocin D20079. In this paper, mode of action using three various concentrations of acidocin D20079 (2,048, 128 and 11.3 AU/ml) was determined against an indicator strain L. delbrueckii subsp. lactis DSM 20076. These concentrations all led to marked decreases in both the number of viable cells and in optical density, indicating that the activity of the acidocin D20079 was bactericidal with concomitant cell lysis. Moreover, the probiotic potential of L. acidophilus DSM 20079 was analyzed for its ability to survive and retain viability at conditions (acid and bile concentrations) mimicking the gastrointestinal (GI) tract, under which it survived exposure to pH 2.0 with a 1.2 log cycle reduction in viability and where 45% of the original population survived in a medium containing 0.3% bile for 3 h.
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| 3. |
- Deraz, Sahar, et al.
(author)
-
Production and physicochemical characterization of acidocin D20079, a bacteriocin produced by Lactobacillus acidophilus DSM 20079
- 2007
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In: World Journal of Microbiology & Biotechnology. - : Springer Science and Business Media LLC. - 0959-3993 .- 1573-0972. ; 23:7, s. 911-921
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Journal article (peer-reviewed)abstract
- Lactobacillus acidophilus DSM 20079 is the producer of a novel bacteriocin termed acidocin D20079. In this paper, a partial sequence of this peptide is determined, together with data on its secondary structure. A modification of the MRS-growth medium (replacing the detergent Tween 80 with oleic acid), was shown to improve the production level of the peptide by one order of magnitude, as well as to stabilize the activity level. Addition of a detergent (Tween 20, less interfering in mass spectrometric analysis), was however necessary for solubilization of the purified acidocin D20079. Digestion of the peptide followed by de-novo sequencing of generated fragments, allowed determination of a partial sequence consisting of 39 of the totally estimated 65 residues. Acidocin D20079 has a high content of glycine residues, hydrophobic residues, and acidic residues. No modified amino acids were found. Edman degradation, and C-terminal sequencing failed, suggesting that the peptide may be cyclic, and a novel member of class IIc bacteriocins. Circular dichroism spectroscopy and secondary structure prediction showed random coil conformation in aqueous solution, but secondary structure was induced in the presence of sodium-dodecyl sulfate. The data could be fitted assuming 2-13% of the residues to be in alpha-helix and 23-27% of the residues to be in beta-strand conformation. This indicates that a membrane/membrane-mimicking hydrocarbon-water interface induces an active conformation.
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