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Conventional degreasing of skins and hides in the leather industry requires high amounts of organic solvents and detergents that cause environmental issues. In this study, the LIP2 lipase from the yeast Yarrowia lipolytica (YLLIP2) was shown to be effective in degreasing sheepskins, thus reducing the amount of harmful chemicals. Using 6 mg of lipase/kg of raw skin, successful degreasing was achieved in only 15 min at pH 8 and 30°C. ToF-SIMS mass spectra of chemically and enzymatically treated sheepskins are consistent with a selective elimination process for the enzymatic treatment. Comparative SEM microscopy, ATR-FTIR spectroscopy and physicochemical analyses showed better properties of the enzymatically treated leather than those of the chemical treatment. Effluent physicochemical parameters showed that the enzymatic treatment is a cleaner degreasing operation. Altogether, this work opens new horizons to use the YLLIP2 lipase as a more efficient alternative in the leather industry., (Copyright © 2022 Elsevier B.V. All rights reserved.)

The extremely halophilic archaeon Halobacterium salinarum strain ETD5 was previously isolated from the solar saltern of Sfax (Tunisia) and shown to encode and express halocin S8. The Hbt. salinarum ETD5 culture supernatant was shown here to exhibit high antimicrobial activity against several halophilic archaea and bacteria of different genera, showing a cross-domain inhibition. The antimicrobial activity was destroyed by proteases, thus pointing to halocins. A bioguided purification procedure was applied using two chromatography steps and antimicrobial assays directed against Halorubrum chaoviator ETR14. In-gel screening assay showed the presence of two antimicrobial bands of approximately 8 and 14 kDa, for which characterization was investigated by N-terminal sequencing and mass spectrometry. The full-length form of halocin S8 that contains 81 amino acids and differs from the 36 amino acid short-length halocin S8 previously described from an uncharacterized haloarchaeon S8a, was identified in the 8 kDa halocin band. A novel halocin that we termed halocin S14 was found in the 14 kDa band. It exhibits amino acid sequence identities with the N-terminally truncated region of the archaeal Mn-superoxide dismutase. These results show that Hbt. salinarum ETD5 produces multiple halocins, a feature that had not been described until now in the domain Archaea., (Copyright © 2019 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.)

The use of an immobilized Serratia. sp W3 lipase as a replacement for the standard pancreatic lipases in the hydrolysis of liver oil from the Musteleus mustelus was studied. Monoacylglycerols (MAGs) and diacylglycerols (DAGs) containing ω-3 polyunsaturated fatty acids, namely eicosapentaenoic and docosahexaenoic acids were produced in hexane solvent at reaction temperatures reaching 55 °C with a molar triacylglycerol conversion over than 75 ± 5% in 24 h showing excellent hydrolysis characteristics. The favorable conditions for the hydrolysis reaction allowed fats with higher melting points to be analyzed facilitating the coupling of the hydrolysis reaction to the later steps in the analytical protocol. The lipid composition was elucidated for the first time by employing a highly efficient UHPLC-MS method with a novel embedded linear retention index approach. MAGs and DAGs obtained during the enzymatic hydrolysis could be used for the production of glycerol based emulsifiers of nutritional interest., Competing Interests: Declaration Competing of Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2019. Published by Elsevier B.V.)

Marine species have gained significant attention as potential source for a broad spectrum of bioactive proteins. Fish phospholipases A 2 (PLA 2 ) have attracted renewed interest due to their excellent properties in lipid digestion. Herein, we report for the first time the catalytic properties of two intestinal secreted PLA 2 (sPLA 2 ) identified from Diplodus sargus (IDsPLA 2 ) and Sparus aurata (ISaPLA 2 ). The highest sequence identity was obtained with recently isolated Sparidae digestive PLA 2 (45%) and Human pancreatic PLA 2 (42%). IDsPLA 2 and ISaPLA 2 were overexpressed in E. coli as inclusion bodies, refolded and purified. Both enzymes have improved thermostability compared to mammalian pancreatic sPLA 2 since they are active and stable at 55 °C, with specific activities of 320 and 190 U mg -1 measured on phosphatidylcholine, respectively. Interestingly, IDsPLA 2 , but not ISaPLA 2 , revealed weak toxicity towards macrophages and suggests its involvement in cell membrane degradation. ISaPLA 2 was found to be more active than IDsPLA 2 when using the monolayer technique at 20 mN m -1 . Structural models of both enzymes revealed their differences. In silico docking of phospholipids with both models allowed proposing key amino-acids in substrate binding and selectivity. Overall, these results provide insight into the enzymatic and structural properties of two novel sPLA 2 with potential for future applications., (Copyright © 2019 Elsevier B.V. All rights reserved.)

The main purpose of this work was to investigate some physiochemical and antioxidant properties of purified proteins of 18 kDa from black cumin seeds. The structural properties of purified proteins were characterized using Fourier Transform-Infrared spectroscopy (FT-IR) and Circular dichroism (CD) spectroscopy analysis. The Tunisian purified protein exhibited a α-helix structure and the Turkish purified protein adopted a β-sheet conformation. The thermal properties were also evaluated by differential scanning calorimetry (DSC). The Tunisian purified protein presented two endothermic peaks, the first one was at 76.71 °C and the second one was at 131.32 °C. However, only one endothermic peak was found for the Turkish purified protein at 157.63 °C. Both Tunisian and Turkish purified proteins were very stable towards heat-induced denaturation. In addition, the effect of pH, salt (NaCl and Na 2 SO 4 ) and temperature on functional properties was investigated. The Tunisian black cumin seeds pure protein exhibited better antioxidant activity than that of the Turkish one at all tested concentrations (0.2 to 1 mg/mL) and temperatures (50 °C, 75 °C and 100 °C), as well as after gastrointestinal digestion simulation., (Copyright © 2018. Published by Elsevier B.V.)

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., (Copyright © 2018 Elsevier B.V. All rights reserved.)

A lipolytic activity was located in the chicken uropygial glands, from which a carboxylesterase (CUE) was purified. Pure CUE has an apparent molecular mass of 50 kDa. The purified esterase displayed its maximal activity (200 U/mg) on short-chain triacylglycerols (tributyrin) at a temperature of 50°C. No significant lipolytic activity was found when medium chain (trioctanoin) or long chain (olive oil) triacylglycerols were used as substrates. The enzyme retained 75% of its maximal activity when incubated during 2h at 50°C. The NH(2)-terminal amino acid sequence showed similarities with the esterase purified recently from turkey pharyngeal tissue. Esterase activity remains stable after its incubation during 30 min in presence of organic solvents such as hexane or butanol. CUE is a serine enzyme since it was inactivated by phenylmethanesulphonyl fluoride (PMSF), a serine-specific inhibitor. The purified enzyme, which tolerates the presence of some organic solvent and a high temperature, can be used in non-aqueous synthesis reactions. Hence, the uropygial esterase immobilised onto CaCO(3) was tested to produce the isoamyl and the butyl acetate (flavour esters). Reactions were performed at 50°C in presence of hexane. High synthesis yields of 91 and 67.8% were obtained for isoamyl and butyl acetate, respectively., (Copyright © 2012 Elsevier B.V. All rights reserved.)

A marine snail digestive phospholipase A2 (mSDPL) was purified from delipidated hepatopancreas. Unlike known digestive phospholipases A2, which are 14 kDa proteins, the purified mSDPL has a molecular mass of about 30 kDa. It has a specific activity of about 180 U/mg measured at 50 degrees C and pH 8.5 using phosphatidylcholine liposomes as a substrate in the presence of 4 mM NaTDC and 6mM CaCl2. The N-terminal amino-acid of the purified mSDPL does not share any homology with known phospholipases. Moreover, the mSDPL exhibits hemolytic activity in intact erythrocytes and can penetrate phospholipid monolayers at high surface pressure, comparable to snake venom PLA2. These observations suggest that mSDPL could be toxic to mammal cells. However, mSDPL can be classified as a member of a new family of enzymes. It should be situated between the class of toxic phospholipase A2 from venoms and another class of non toxic pancreatic phospholipase A2 from mammals., (2009 Elsevier Inc. All rights reserved.)