Production, purification and biochemical characterization of a thermoactive, alkaline lipase from a newly isolated Serratia sp. W3 Tunisian strain.

A newly isolated Serratia sp. W3 strain was shown to secrete a non-induced lipase in the culture medium. Lipolytic activity was optimized using the response surface methodology (RSM) and the extracellular lipase from Serratia sp. W3 (SmL) was purified to homogeneity with a total yield of 10% and its molecular mass was estimated of about 67 kDa by SDS-PAGE. The amino acid sequence of the first 7 N-terminal residues of SmL revealed a high degree of homology with other Serratia lipase sequences. The purified SmL can be considered as thermoactive lipase, its maximal specific activity measured at pH 9 and 55 °C was shown to be 625 U/mg and 300 U/mg using tributyrin and olive oil emulsion as substrate, respectively. In contrast to other described Serratia lipases, SmL was found to be stable at a large scale of pH between pH 5 and pH 12. SmL was also able to hydrolyze its substrate in presence of various oxidizing agents as well as in presence of surfactants and some commercial detergents. Then, considering the overall biochemical properties of SmL, it can be considered as a potential candidate for industrial and biotechnological applications, such as synthesis of biodiesel and in the detergent industry.

Synergistic effect of polysaccharides, betalain pigment and phenolic compounds of red prickly pear (Opuntia stricta) in the stabilization of salami.

The aim of this work is to try to substitute some synthetic additives by a natural extract from red prickly pear (Opuntia stricta) which known by its richness on bioactive polysaccharides mainly consisting of galactose, rhamnose and galacturonic acid. This natural fruit has a high content of carbohydrates above 18.81% FM. It contains also a high level of polyphenols 152.25 ±â€¯0.26 µg QE/mg PPE and flavonoids about 370.60 ±â€¯0.12 µg GAE/mg of PPE. In addition, prickly pear extract (PPE) displayed a strong antioxidant and antimicrobial activities. These activities are likely due to its phenolic, flavonoid and carbohydrate contents. Moreover, the addition of 2.5% of PPE, as a natural colorant and antimicrobial agent in salami formulation, causes a decrease in hardness and chewiness of the formulated salami. Interestingly, PPE inhibited bacterial growth in salami stored at 4 °C over 30 days. Sensorial analysis shows that the color, taste and texture of salami prepared with 2.5% of PPE are markedly more appreciated by panelists. Our results suggest that the betalain pigment, carbohydrate and phenolic compounds present in PPE could be used as a natural colorant, antioxidant and antimicrobial agent without change of the sensory characteristics.

Enzymatic synthesis of 1,3-dihydroxyphenylacetoyl-sn-glycerol: Optimization by response surface methodology and evaluation of its antioxidant and antibacterial activities.

In this study, the enzymatic synthesis of phenylacetoyl glycerol ester was carried out as a response to the increasing consumer demand for natural compounds. 1,3-dihydroxyphenylacetoyl-sn-Glycerol (1,3-di-HPA-Gly), labeled as "natural" compound with interesting biological properties, has been successfully synthesized for the first time in good yield by a direct esterification of glycerol (Gly) with p-hydroxyphenylacetic acid (p-HPA) using immobilized Candida antarctica lipase as a biocatalyst. Spectroscopic analyses of purified esters showed that the glycerol was mono- or di-esterified on the primary hydroxyl group. These compounds were evaluated for their antioxidant activity using two different tests. The glycerol di-esters (1,3-di-HPA-Gly) showed a higher antiradical capacity than that of the butyl hydroxytoluene. Furthermore, compared to the p-HPA, synthesized ester (1,3-di-HPA-Gly) exhibited the most antibacterial effect mainly against Gram + bacteria. Among synthesized esters the 1,3-di-HPA-Gly was most effective as antioxidant and antibacterial compound. These findings could be the basis for a further exploitation of the new compound, 1,3-di-HPA-Gly, as antioxidant and antibacterial active ingredient in the cosmetic and pharmaceutical fields.

Valorization of antioxidants extracted from olive mill wastewater.

Antioxidants are highly important gradients used to preserve cosmetic products and reduce the effect of oxidative stress on the skin. The present work explores the possibility of using phenolic compounds of olive mill wastewater (OMW) as effective alternatives to the commercial antioxidants used in cosmetic formulations deemed by their allergic and carcinogenic effects. Esterification of tyrosol and hydroxytyrosol extracted from OMW with various fatty acids was conducted using Novozyme 435 lipase as a biocatalyst. Upon synthesis, butyrate, caprate, laurate, and palmitate tyrosyl and hydroxytyrosyl esters were isolated and evaluated for their antioxidant and antibacterial activities. Results showed that laurate derivatives are the most efficient in preventing lipid oxidation and inhibiting growth of pathogenic strains. In the prospective of industrial use, laurate tyrosyl and hydroxytyrosyl derivatives were incorporated in a formulation of moisturizer to substitute the commercial antioxidant butylated hydroxyltoluene. Oleuropein, extracted from olive leaves powder, was also tested as an antiaging ingredient in cosmetic formulations. The evaluation of physicochemical, microbiological, and sensorial properties of the new cosmetic products indicated that oleuropein and lipophilic derivatives do not affect the properties of the standard formulation. Oleuropein and lipophilic derivatives can be added as active ingredients to stabilize cosmetic preparations.

Oil from pumpkin (Cucurbita pepo L.) seeds: evaluation of its functional properties on wound healing in rats.

BACKGROUND: Increasing natural drug demand for pharmaceutical uses has encouraged scientifics all over the world to explore medicinal plants recognized as efficient remedies. In this context, extracted oil from pumpkin seeds (Cucurbita pepo L.) is an interesting target, as it is composed with prominent pharmacological properties to possible wound healing treatments. METHODS: The composition and content of certain bioactive constituents of the cold pressed oil obtained from pumpkin seeds (Cucurbita pepo L.) were analyzed and studied for their wound healing properties. Uniform wounds were induced on the dorsum of 18 rats, randomly divided into three groups. The wounds were photographed, and topically treated with saline solution (control group), 0.13 mg/mm(2) of a reference drug ("Cicaflora cream®"), and 0.52 µl/mm(2) of pumpkin's oil each 2 days until the first group is completely healing and so far biopsies were histologically assessed. RESULTS: The composition and content of tocopherols, fatty acids, and phytosterols were determined. The results showed an excellent quality of pumpkin oil with high content of polyunsaturated fatty acids (Linoleic acid: 50.88 ± 0.106 g/100 g of total fatty acids), tocopherols (280 ppm) and sterols (2086.5 ± 19.092 ppm). High content of these bioactive components were in agreement with an efficient wound healing by the mean of an in vivo study. In fact, morphometric assessment and histological findings revealed healed biopsies from pumpkin oil treated group of rats, unlike untreated group, and a full re-epithelialization with reappearance of skin appendages and well organized collagen fibers without inflammatory cells. CONCLUSIONS: This study showed the significance of oil from pumpkin seeds (Cucurbita pepo L.) as a promising drug to healing wounds in animal assays. As a whole, pumpkin's oil would be recommended in the nutritional and medicinal purposes.