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Table olives, a vital category among fermented vegetables, come in treated and natural forms. Treated green olives require an alkaline treatment before brining to start fermentation. This study investigates the fermentation of unsalted Moroccan Picholine green olives using a method that includes heat shock treatment, inoculation with Lactiplantibacillus plantarum S61, and orange peel juice. The findings indicate that a heat shock at 70°C significantly reduces enterobacteria and enhances acidification, dropping pH levels from 5.0 to 3.6. In contrast, non-heat-treated olives showed only a slight pH decrease. The method also exhibited high antimicrobial activity, with substantial inhibition of E. coli, P. aeruginosa, L. monocytogenes, and S. aureus. Antifungal activity was noted, with significant inhibition of various strains. These results suggest that combining heat shock, L. plantarum S61, and orange peel juice can significantly improve the fermentation process of green olives, enhancing safety and quality.

This work describes the immobilization and the characterization of purified Penicillium crustosum Thom P22 lipase (PCrL) using adsorption, encapsulation, and adsorption–encapsulation approaches. The maximum activity of the immobilized PCrL on CaCO3 microspheres and sodium alginate beads was shifted from 37 to 45 °C, compared with that of the free enzyme. When sodium alginate was coupled with zeolite or chitosan, the immobilization yield reached 100% and the immobilized PCrL showed improved stability over a wide temperature range, retaining all of its initial activity after a one-hour incubation at 60 °C. The immobilization of PCrL significantly improves its catalytic performance in organic solvents, its pH tolerance value, and its thermal stability. Interestingly, 95% and almost 50% of PCrL's initial activity was retained after 6 and 12 cycles, respectively. The characteristics of all PCrL forms were analyzed by X-ray diffraction and scanning electron microscopy combined with energy dispersive spectroscopy. The maximum conversion efficiency of oleic acid and methanol to methyl esters (biodiesel), by PCrL immobilized on CaCO3, was 65% after a 12 h incubation at 40 °C, while free PCrL generated only 30% conversion, under the same conditions. [ABSTRACT FROM AUTHOR]

Biological preservatives are increasingly in demand as an alternative to chemicals, because of consumer's health and environmental concerns. Lactic acid bacteria isolated from fermented olives, considered as extreme environment, may encompass significant antimicrobial activity against microorganisms involved in foodborne diseases and food spoilage. Three LAB strains (Levilactobacillus brevis S27, Lactiplantibacillus pentosus S42, and Lactiplantibacillus plantarum S62), isolated from fermented olive, were studied for their antimicrobial activity against pathogenic bacteria (Listeria innocua and E. coli) and yeast (Rhodotorula glutinis), involved in foodborne diseases and food spoilage. The microbial culture, cell-free supernatant (CFS) of all LAB strains showed inhibition zone (IZ) values ranges of 26.33-28.83 mm, 14.16-16.33 mm and 10-12.16 mm against R. glutinis, L. innocua and E. coli, respectively. The IZ values ranges obtained with NCFS (neutralized CFS at pH 7) against R. glutinis and L. innocua were respectively of 17.83-20.50 mm and 13.16-14.50 mm, whereas no inhibition was obtained against E. coli. Their bioactive molecules of proteinaceous nature showed that among the four peptide bands obtained, two bands of approximately 42 and 56 kDa are common for the three LAB strains (S27, S42 and S62). Two additional bands of 46 and 89kD are observed in S42 and S27, respectively. The minimum inhibitory concentration of 10-fold concentrated CFS (10xCFS) obtained was 5% against E. coli and 4.5% against L. innocua and R. glutinis. The 10xCFS of Lb. plantarum S62, selected as the most efficient strain against pathogens, demonstrated its effectiveness in decontamination of milk at concentrations of 0.45% (v/v) and 0.5% (v/v) against L. innocua and E. coli. The CFS allowed, at 0.5 mL/piece of 5 cm diameter, a total inhibition of R. glutinis, without affecting the color of Pastilla leaf. The CFS of Lb. plantarum S62 can be used as a bio-preservative against pathogenic bacteria (L. innocua and E. coli) in milk, and against R. glutinis in Pastilla leaf. [ABSTRACT FROM AUTHOR]

A novel extracellular lipase from a filamentous fungus Ascomycota strain, P22, was isolated from olive mill wastewater, then purified and characterized. This strain was identified as Penicillium crustosum Thom based on sequencing analyses. Penicilliumcrustosum Thom strain P22 lipase (PCrL) was purified 63-fold to homogeneity using ammonium sulfate precipitation and chromatography on a Q-Sepharose Fast Flow column, with a total yield of 34%. The purified PCrL had a molecular mass of 28 kDa, estimated by SDS-PAGE. The 20 NH2-terminal amino-acid residues showed a high degree of homology with those of other Penicillium lipases. The specific activity of PCrL at pH 9 and 37 °C were found to be 5000 and 10,000 U/mg on olive oil and trioctanoin emulsions, respectively. PCrL exhibited clear regioselectivity toward the sn-1 position of the surface-coated triglycerides which were esterified with α-eleostearic acid at the sn-1/3 position. PCrL was completely inhibited by 53 µM of Orlistat, 5 mM of phenylmethylsulfonylfluoride, and 2 mM of diiodopropyl fluorophosphate, suggesting that it belonged to the serine lipase family. PCrL showed high activity and stability in the presence of water-immiscible organic solvents, surfactant, and oxidizing agents, and showed considerable compatibility with commercial laundry detergents. Washing performance analysis revealed that it could effectively remove oil stains. Hence, PCrL has several attractive properties that make it a promising potential candidate for detergent formulations. [ABSTRACT FROM AUTHOR]

Abstract Background Phospholipase D (PLD) belongs to a lipolytic enzyme subclass which catalyzes the hydrolysis and transesterification of glycerophospholipids at the terminal phosphodiester bond. Results In this work, we have studied the substrate specificity of PLDs from germinating sunflower seeds and cultured-soybean cells, using their capacity of transphosphatidylation. In the presence of a nucleophilic acceptor, such as [14C]ethanol, PLD catalyzes the production of phosphatidyl-[14C]-ethanol. The resulting product is easily identified since it is well separated from the other lipids by thin-layer chromatography. The main advantage of this assay is that the phospholipid used as substrate does not need to be radiolabelled and thus allow us a large choice of polar heads and fatty acids. In vitro, we observed that sunflower and soybean cell PLD show the following decreasing order of specificity: phosphatidylcholine, phosphatidylethanolamine and phosphatidylglycerol; while phosphatidylserine and phosphatidylinositol are utilized much less efficiently. Conclusions The substrate specificity is modulated by the fatty acid composition of the phosphatidylcholine used as well as by the presence of other charged phospholipids.