Effects of pectinolytic yeast on the microbial composition and spoilage of olive fermentations

This study resulted in the identification of pectinolytic yeasts in directly brined Sicilian-style green olive fermentations and examination of the influence of those yeasts on the microbial composition and quality of fermented olives. Firstly, defective olives processed in Northern California from 2007 to 2008 and characterized by high levels of mesocarp tissue degradation were found to contain distinct yeast and bacterial populations according to DNA sequence-based analyses. Strains of (pectinolytic) Saccharomyces cerevisiae, Pichia manshurica, Pichia kudriavzevii, and Candida boidinii isolated from directly brined olives were then inoculated into laboratory-scale olive fermentations to quantify the effects of individual yeast strains on the olives. The pH, titratable acidity, and numbers of lactic acid bacteria (LAB) and yeasts varied between the fermentations and fermentations inoculated with P. kudriavzevii and C. boidinii promoted the development of LAB populations. Olive tissue structural integrity declined significantly within 30, 74, and 192 days after the inoculation of pectinolytic S. cerevisiae, P. manshurica and C. boidinii, respectively. In comparison, tissue integrity of olives in control fermentations remained intact although pectinolytic yeasts were present. Notably, pectinolytic yeasts were not found in fermentations inoculated with (non-pectinolytic) P. kudriavzevii and olives exposed to a 1:1 ratio of P. kudriavzevii and P. manshurica exhibited no significant tissue defects. This study showed that pectinolytic yeast are important components of directly brined green olive fermentations and damage caused by pectinolytic yeasts might be prevented by other microbial colonists of the olives.     

Antiproliferative activity of Dioclea violacea lectin in CaCO3 particles on cancer cells after controlled release

Journal of Materials Science - Cancer is a serious health problem mainly characterized by unregulated cell divisions. It is known that malign cells display cancer-specific glycans that can be...     

Hydrochar as protein support: preservation of biomolecule properties with non-covalent immobilization

In this work, the ConBr lectin was non-covalently immobilized onto hydrochar (HC). This carbonaceous material was produced by the hydrothermal carbonization of glucose and then put to interact with the lectin, aiming to immobilize the biomolecule via electrostatic interactions. Samples obtained after the interaction were characterized by CHNS elemental analysis, scanning electron microscopy and Fourier transform infrared spectroscopy (FTIR). FTIR results from the conjugated sample identified the presence of NH₂ ⁺ and NH₃ ⁺ groups of the protein and COO^? groups of the HC, indicating the occurrence of electrostatic interaction between the biomolecule and the support. Furthermore, the immobilization experiment was also performed using ConBr lectin marked with fluorescein isothiocyanate to assess the immobilization on the hydrochar using fluorescence emission analysis. Hemagglutination tests revealed that even after the conjugation with the HC, the agglutinating property of lectin toward erythrocytes (red blood cells) was preserved. Finally, our results indicate that non-covalent interactions represent an efficient mechanism for protein immobilization on the HC while maintaining the protein structure and its biological activity.