Volume 57, Issue No. 1
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https://doi.org/10.17113/ftb.57.01.19.5816 |
Innovative Nonthermal Technologies: Chlorophyllin and Visible Light Significantly Reduce Microbial Load on Basil
Egle Paskeviciute
, Bernadeta Zudyte and Zivile Luksiene*
Vilnius University, Institute of Photonics and Nanotechnology, Sauletekio 10, 10223 Vilnius, Lithuania
Article history:
Received: 23 April 2018
Accepted: 21 December 2018
Key words:
photosensitization, antimicrobial technology, fresh produce, Ocimum basilicum
Summary:
Due to the high amount of biologically active compounds, basil is one of the most popular herbs. However, several outbreaks have been reported in the world due to the consumption of basil contaminated with different food pathogens. The aim of this study is to apply nonthermal and ecologically friendly approach based on photosensitization for microbial control of basil which was naturally contaminated with mesophils and inoculated with thermoresistant food pathogen Listeria monocytogenes 56Ly. The obtained data indicate that soaking the basil in 1.5·10-4 M chlorophyllin (Chl) for 15 min and illumination with light for 15 min at 405 nm significantly reduced total aerobic microorganisms on basil by 1.3 log CFU/g, and thermoresistant L. monocytogenes 56Ly from 6.1 log CFU/g in control to 4.5 log CFU/g in the treated samples. It is important to note that this treatment had no impact on enzymatic activity of polyphenol oxidase and pectinesterase. Results obtained in this study support the idea that photosensitization technique with its high selectivity, antimicrobial efficiency and nonthermal nature can serve in the future for the development of safe nonthermal and environmentally friendly preservation technology for different fruits and vegetables.
*Corresponding author: 
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https://doi.org/10.17113/ftb.57.01.19.5685 |
Novel Approach in the Construction of Bioethanol-Producing Saccharomyces cerevisiae Hybrids
Anamarija Štafa1, Bojan Žunar1, Andrea Pranklin1, Antonio Zandona1, Marina Svetec Miklenić1, Božidar Šantek2 and Ivan Krešimir Svetec1*
1University of Zagreb, Faculty of Food Technology and Biotechnology, Department of Biochemical Engineering, Laboratory for Biology and Microbial Genetics, Kršnjavoga 25, 10000 Zagreb, Croatia
2University of Zagreb, Faculty of Food Technology and Biotechnology, Department of Biochemical Engineering, Laboratory for Biochemical Engineering, Industrial Microbiology and Malting and Brewing Technology, Kačićeva 28, 10000 Zagreb, Croatia
Article history:
Received: 25 January 2018
Accepted: 10 December 2018
Key words:
yeast Saccharomyces cerevisiae, intraspecies hybrids, lignocellulosic hydrolysates, growth and fermentation inhibitors, gene targeting
Summary:
Bioethanol production from lignocellulosic hydrolysates requires a producer strain that tolerates both the presence of growth and fermentation inhibitors and high ethanol concentrations. Therefore, we constructed heterozygous intraspecies hybrid diploids of Saccharomyces cerevisiae by crossing two natural S. cerevisiae isolates, YIIc17_E5 and UWOPS87-2421, a good ethanol producer found in wine and a strain from the flower of the cactus Opuntia megacantha resistant to inhibitors found in lignocellulosic hydrolysates, respectively. Hybrids grew faster than parental strains in the absence and in the presence of acetic and levulinic acids and 2-furaldehyde, inhibitors frequently found in lignocellulosic hydrolysates, and the overexpression of YAP1 gene increased their survival. Furthermore, although originating from the same parental strains, hybrids displayed different fermentative potential in a CO2 production test, suggesting genetic variability that could be used for further selection of desirable traits. Therefore, our results suggest that the construction of intraspecies hybrids coupled with the use of genetic engineering techniques is a promising approach for improvement or development of new biotechnologically relevant strains of S. cerevisiae. Moreover, it was found that the success of gene targeting (gene targeting fidelity) in natural S. cerevisiae isolates (YIIc17_E5α and UWOPS87-2421α) was strikingly lower than in laboratory strains and the most frequent off-targeting event was targeted chromosome duplication.
*Corresponding author: 
+38514836013
+38514836016
§The paper was presented at European Biotechnology Congress, 25-27 May 2017, Dubrovnik, Croatia
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https://doi.org/10.17113/ftb.57.01.19.5879 |
In Vitro Assessment of the Antioxidant Properties of Aqueous Byproduct Extracts of Vitis vinifera
Roberto Puglisi1*, Alex Severgnini1, Aldo Tava2 and Marina Montedoro1
1Istituto Sperimentale Italiano Lazzaro Spallanzani, Loc. La Quercia, 26027 Rivolta d’Adda (CR), Italy
2CREA-ZA Centro di Ricerca Zootecnia e Acquacoltura, Viale Piacenza 29, 26900 Lodi, Italy
Article history:
Received: 1 June 2018
Accepted: 31 January 2019
Key words:
non-cytotoxic effect, extraction at low temperature, human dermal fibroblasts, oxidative status, mitochondrial membrane
Summary:
Aqueous extracts were obtained at low temperature with the Naviglio technology from grapevine stalks (Merlot), marc (Merlot and Cabernet Sauvignon) and leaves (Merlot) as typical byproducts of winemaking industry, and their properties were evaluated cytofluorometrically on human dermal fibroblasts. Leaf extracts had the greatest total phenolic ((47.6±3.5) mg/g) and proanthocyanidin ((24.2±0.1) mg/g) contents compared to the others. The preliminary colorimetric MTT (3-[4,5-dimethylthiazole-2-yl]-2,5-diphenyltetrazolium bromide) assay individuated two consecutive non-toxic volume fractions of each extract (from 0.8 to 12.8 %) that were adopted for three cytofluorometric tests. The first cell membrane test did not evidence any harmful effects against plasma membranes at the two non-toxic volume fractions. The second mitochondrial membrane test showed a decreased (p<0.01) percentage of cells ((15.7±8.3) vs (32.5±1.3) %) with active polarized mitochondrial membranes at the higher non-cytotoxic volume fractions of extracts from Cabernet Sauvignon marc in response to 4.5 mM H2O2, and from Merlot stalks (p<0.05) at 1.5 mM H2O2 ((49.3±6.1) vs (64.6±2.4) %) and without H2O2 ((89.7±2.4) vs (96.9±1.8) %), compared to the controls submitted to the same H2O2 concentration. Conversely, mitochondrial activity of leaf extracts significantly (p<0.05) increased ((96.3±1.8) and (96.4±1.4) %) after treatment with 0.5 mM H2O2 at both non-cytotoxic volume fractions compared to control ((88.2±1.1) %). Finally, as evidenced by the third oxidative status test, stalk extracts did not evidence relevant effects on the cellular oxidative state, while the extracts of marc and leaves demonstrated significantly medium (p<0.05) to highly (p<0.001) positive effects following exposure to H2O2 ranging from 0.5 to 4.5 mM, compared to controls.
*Corresponding author: +39036378883
+390363371021