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Ezzine A, Ben Hadj Mohamed S, Bezzine S, Aoudi Y, Hajlaoui MR, Baciou L, Smaali I. Improved Expression of a Thermostable GH18 Bacterial Chitinase in Two Different Escherichia coli Strains and Its Potential Use in Plant Protection and Biocontrol of Phytopathogenic Fungi. Mol Biotechnol 2024:10.1007/s12033-023-01041-1. [PMID: 38265740 DOI: 10.1007/s12033-023-01041-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Accepted: 12/18/2023] [Indexed: 01/25/2024]
Abstract
Chitinases are enzymes that can break down chitin, a major component of the exoskeleton of insects and fungi. This feature makes them potential biopesticides in agriculture since they are considered a safe and environmentally friendly alternative to synthetic pesticides. In this work, we performed a comparative study between two different bacterial expression strains to produce a recombinant chitinase with improved stability. Escherichia coli strains Origami B and BL21 (DE3) were selected for their distinct cytosolic environment to express BhChitA chitinase of Bacillus halodurans C-125 and to investigate the role of disulfide bond formation and proper folding on its stability and activity. Expression of the recombinant BhChitA in bacterial strain containing oxidative cytosol (Origami B) improved its activity and stability. Although both expression systems have comparable biochemical properties (temperature range 20-80 °C and pH spectrum 3-10), BhChitA expressed in Origami strain seems more stable than expressed in BL21. Furthermore, the optimal expression conditions of the recombinant BhChitA has been carried out at 30 °C during 6 h for the Origami strain, against 20 °C during 2 h for BL21. On the other hand, no significant differences were detected between the two enzymes when the effect of metal ions was tested. These findings correlate with the analysis of the overall structure of BhChitA. The model structure permitted to localize disulfide bond, which form a stable connection between the substrate-binding residues and the hydrophobic core. This link is required for efficient binding of the chitin insertion domain to the substrate. BhChitA exhibited in vitro antifungal effect against phytopathogenic fungi and suppressed necrosis of Botrytis cinerea on detached tomato leaves. In vitro assays showed the influence of BhChitA on growth suppression of Botrytis cinerea (53%) Aspergillus niger (65%), Fusarium graminearum (25%), and Fusarium oxysporum (34%). Our results highlight the importance of the bacterial expression system with oxidative cytosol in producing promising biopesticides that can be applied for post-harvest processing and crop protection.
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Affiliation(s)
- Aymen Ezzine
- Laboratory of Protein Engineering and Bioactive Molecules (LIP-MB), LR11ES24, National Institute of Applied Sciences and Technology, University of Carthage, 1080, Tunis Cedex, Tunisia.
- Higher Institute of Preparatory Studies in Biology and Geology (ISEP-BG), 49 Avenue 13 Août, Choutrana II, 2036, Soukra, Tunisia.
| | - Safa Ben Hadj Mohamed
- Laboratory of Protein Engineering and Bioactive Molecules (LIP-MB), LR11ES24, National Institute of Applied Sciences and Technology, University of Carthage, 1080, Tunis Cedex, Tunisia
| | - Sofiane Bezzine
- Laboratory of Protein Engineering and Bioactive Molecules (LIP-MB), LR11ES24, National Institute of Applied Sciences and Technology, University of Carthage, 1080, Tunis Cedex, Tunisia
- Higher Institute of Preparatory Studies in Biology and Geology (ISEP-BG), 49 Avenue 13 Août, Choutrana II, 2036, Soukra, Tunisia
| | - Yosra Aoudi
- Laboratory of Protein Engineering and Bioactive Molecules (LIP-MB), LR11ES24, National Institute of Applied Sciences and Technology, University of Carthage, 1080, Tunis Cedex, Tunisia
- Department of Biological Production Science, United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, 3-5-8 Saiwaicho, 183-8509, Fuchu, Japan
| | - Mohamed Rabeh Hajlaoui
- National Institute of Agronomic Research (INRAT), Laboratory of Biotechnology Applied to Agriculture, 1004, El Menzah, Tunis, Tunisia
| | - Laura Baciou
- Institut de Chimie Physique UMR 8000, CNRS, Université Paris-Saclay, 91405, Orsay, France
| | - Issam Smaali
- Laboratory of Protein Engineering and Bioactive Molecules (LIP-MB), LR11ES24, National Institute of Applied Sciences and Technology, University of Carthage, 1080, Tunis Cedex, Tunisia
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Khemiri S, Nunes MC, Raymundo A, Smaali I. In vitro
starch digestibility and estimation of glycemic index in algae‐based couscous. Int J Food Sci Technol 2022. [DOI: 10.1111/ijfs.16073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Sheyma Khemiri
- University of Carthage INSAT, Laboratory of Protein Engineering and Bioactive Molecules (LR11ES24), BP 676, 1080, Cedex Tunisia
| | - M Cristiana Nunes
- LEAF – Linking Landscape, Environment, Agriculture and Food, Instituto Superior de Agronomia, Universidade de Lisboa, Tapada da Ajuda, 1349‐017 Lisboa Portugal
| | - Anabela Raymundo
- LEAF – Linking Landscape, Environment, Agriculture and Food, Instituto Superior de Agronomia, Universidade de Lisboa, Tapada da Ajuda, 1349‐017 Lisboa Portugal
| | - Issam Smaali
- University of Carthage INSAT, Laboratory of Protein Engineering and Bioactive Molecules (LR11ES24), BP 676, 1080, Cedex Tunisia
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Khemiri S, Nunes MC, Bessa RJB, Alves SP, Smaali I, Raymundo A. Technological Feasibility of Couscous-Algae-Supplemented Formulae: Process Description, Nutritional Properties and In Vitro Digestibility. Foods 2021; 10:3159. [PMID: 34945710 PMCID: PMC8701376 DOI: 10.3390/foods10123159] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Revised: 12/06/2021] [Accepted: 12/14/2021] [Indexed: 12/02/2022] Open
Abstract
The aim of this work was to develop functional couscous in a traditional Tunisian manner (hand rolling), enriched in algae biomass (6% w/w). Four Chlorella vulgaris (C. vulgaris) biomasses and one mixture of C. vulgaris and two macroalgae biomasses (Ulva rigida and Fucus vesiculosus) were used. The C. vulgaris strain was subjected to random mutagenesis and different culture conditions (Allmicroalgae), resulting in different pigmentations and biochemical compositions. Couscous samples were characterized in terms of nutritional properties, oscillatory rheology properties and digestibility. All biomasses provided a significant supplementation of nutrients and excellent acceptance. The enrichment resulted in lower firmness, higher viscoelastic functions (G' and G″) and a significant improvement in the cooking quality. Major differences between couscous samples with different microalgae were observed in protein and mineral contents, fully meeting Regulation (EC) No. 1924/2006 requirements for health claims made on foodstuffs. The amount of digested proteins was also higher in algae-containing samples. The fatty acid profile of the enriched couscous varied in a biomass-specific way, with a marked increase in linolenic acid (18:3 ω3) and a decrease in the ω6/ω3 ratio. Sensory analysis revealed that microalgae-containing products could compete with conventional goods with an added advantage, that is, having an ameliorated nutritional value using algae as a "trendy" and sustainable ingredient.
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Affiliation(s)
- Sheyma Khemiri
- Laboratory of Protein Engineering and Bioactive Molecules (LR11ES24), National Institute of Applied Science and Technology, University of Carthage, BP 676, Tunis 1080, Tunisia; (S.K.); (I.S.)
| | - Maria Cristiana Nunes
- LEAF—Linking Landscape, Environment, Agriculture and Food, Instituto Superior de Agronomia, Universidade de Lisboa, Tapada da Ajuda, 1349-017 Lisboa, Portugal;
| | - Rui J. B. Bessa
- CIISA, Faculdade de Medicina Veterinária, Avenida da Universidade Técnica, Pólo Universitário do Alto da Ajuda, 1300-477 Lisboa, Portugal; (R.J.B.B.); (S.P.A.)
| | - Susana P. Alves
- CIISA, Faculdade de Medicina Veterinária, Avenida da Universidade Técnica, Pólo Universitário do Alto da Ajuda, 1300-477 Lisboa, Portugal; (R.J.B.B.); (S.P.A.)
| | - Issam Smaali
- Laboratory of Protein Engineering and Bioactive Molecules (LR11ES24), National Institute of Applied Science and Technology, University of Carthage, BP 676, Tunis 1080, Tunisia; (S.K.); (I.S.)
| | - Anabela Raymundo
- LEAF—Linking Landscape, Environment, Agriculture and Food, Instituto Superior de Agronomia, Universidade de Lisboa, Tapada da Ajuda, 1349-017 Lisboa, Portugal;
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Khemiri S, Bouchech I, Berrejeb N, Mejri M, Smaali I, Khelifi N. Effects of Growth Medium Variation on the Nutri-Functional Properties of Microalgae Used for the Enrichment of Ricotta. Food Technol Biotechnol 2021; 60:29-40. [PMID: 35440884 PMCID: PMC8990991 DOI: 10.17113/ftb.60.01.22.7105] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Accepted: 11/12/2021] [Indexed: 11/12/2022] Open
Abstract
Research background. Microalgae represent an emergent sustainable source of bioactive compounds such as antioxidants, vitamins, minerals, and polyunsaturated fatty acids that can ameliorate the nutritional characteristics of foods. The biochemical composition of microalgae could be modulated by varying the culture conditions to enhance the accumulation of biomolecules of interest. The aim of this work is to optimise the nutri-functional properties of two microalgae with potential utility for food-application.
Experimental approach. Nannochloropsis gaditana.L2 and Chlorella sp.SM1 were screened for growth, biochemical composition, and radical scavenging activity employing four different growth media (Algal, BG-11, f/2, and Conway) with different nutrients composition. Additionally, the feasibility of using Chlorella sp.SM1 cultivated in BG-11 medium, in a Mediterranean under-investigated dairy product “ricotta cheese” and its effect on the sensory attributes was investigated.
Results and conclusions. Nitrate- and phosphate-rich media (BG-11 and Algal) enhanced the biomass productivity. However, the highest lipid productivity (23.10 mg/(L·day); 11.86 mg/(L·day) for SM1 and L2 respectively) and carbohydrates content (34.79 %; 44.84 % for SM1 and L2 respectively) were obtained with the nitrate-deficient f/2 medium. Regardless of the used medium, the lipidic profile of Chlorella sp.SM1 and Nannochloropsis gaditana.L2 remained adequate for different applications with the presence of C16-18 as main fatty acid (>50 %). Significant increase in oleic acid (C18:1) content was recorded in response to nitrogen deficiency, being the highest in SM1 in f/2 medium (34 %). Nitrogen deficiency was also found to enhance phenolic compounds (48.8 GAE/(mg/g); 35.1 GAE/(mg/g) for SM1 and L2 respectively) and carotenoids contents (2.2 mg/g; 2 mg/g for SM1 and L2 respectively). Due to its interesting antioxidant potential, Chlorella sp.SM1 was used to enrich the ricotta cheese product at different concentrations (0.2 %, 1 % and 1.5 %). The sample with 0.2 % was found to give the most appreciated product.
Novelty and scientific contribution. This study permitted the production of an innovative ricotta cheese using Chlorella, as a functional ingredient, without altering the manufacturing diagram while maintaining acceptable sensorial characteristics. The biochemical composition of the used strains varied depending on the culture media’s composition, which permitted the accumulation of phytonutrients of interest.
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Affiliation(s)
- Sheyma Khemiri
- University of Carthage, INSAT, Laboratory of Protein Engineering and Bioactive Molecules (LR11ES24), BP 676, 1080, Cedex, Tunisia
| | - Ines Bouchech
- University of Carthage, Higher Institute of Fisheries and Aquaculture, BP 15, Errimel, 7080, Bizerte, Tunisia
| | - Nadia Berrejeb
- University of Carthage, INSAT, Laboratory of Protein Engineering and Bioactive Molecules (LR11ES24), BP 676, 1080, Cedex, Tunisia
| | - Mondher Mejri
- University of Carthage, INSAT, Laboratory of Protein Engineering and Bioactive Molecules (LR11ES24), BP 676, 1080, Cedex, Tunisia
| | - Issam Smaali
- University of Carthage, INSAT, Laboratory of Protein Engineering and Bioactive Molecules (LR11ES24), BP 676, 1080, Cedex, Tunisia
| | - Nadia Khelifi
- University of Carthage, INSAT, Laboratory of Protein Engineering and Bioactive Molecules (LR11ES24), BP 676, 1080, Cedex, Tunisia
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Lajnef I, Khemiri S, Ben Yahmed N, Chouaibi M, Smaali I. Straightforward extraction of date palm syrup from Phoenix dactylifera L. byproducts: application as sucrose substitute in sponge cake formulation. Food Measure 2021. [DOI: 10.1007/s11694-021-00970-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Anders N, van Ohlen M, Jestel T, Herbst L, Jmel MA, Smaali I, Spiess AC. Uncover aldehydes in biomass hydrolyzates: disproportionation of aldehydes in alkaline solution and subsequent measurement using an automated HPAEC-PAD method. Anal Bioanal Chem 2020; 412:5593-5600. [DOI: 10.1007/s00216-020-02775-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 06/06/2020] [Accepted: 06/17/2020] [Indexed: 11/24/2022]
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Ben Hlel T, Borges T, Rueda A, Smaali I, Marzouki MN, Seiquer I. Polyphenols bioaccessibility and bioavailability assessment in ipecac infusion using a combined assay of simulated
in vitro
digestion and Caco‐2 cell model. Int J Food Sci Technol 2018. [DOI: 10.1111/ijfs.14023] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Takoua Ben Hlel
- LIP‐MB Laboratory (LR11ES24) National Institute of Applied Sciences and Technology, University of Carthage Centre urbain nord de Tunis, B.P. 676 Tunis Cedex 1080 Tunisia
- Department of Biology Faculty of Tunis University of Tunis El Manar Rue de Tolède 2092 Tunis Tunisia
| | - Thays Borges
- Department of Physiology and Biochemistry of Animal Nutrition Estación Experimental del Zaidín (CSIC) Camino del Jueves s/n 18100 Armilla Granada Spain
| | - Ascensión Rueda
- Institute of Nutrition and Food Technology José Mataix Verdú Avenida del Conocimiento s/n. Parque Tecnológico de la Salud 18071 Armilla Granada Spain
| | - Issam Smaali
- LIP‐MB Laboratory (LR11ES24) National Institute of Applied Sciences and Technology, University of Carthage Centre urbain nord de Tunis, B.P. 676 Tunis Cedex 1080 Tunisia
| | - M. Nejib Marzouki
- LIP‐MB Laboratory (LR11ES24) National Institute of Applied Sciences and Technology, University of Carthage Centre urbain nord de Tunis, B.P. 676 Tunis Cedex 1080 Tunisia
| | - Isabel Seiquer
- Department of Physiology and Biochemistry of Animal Nutrition Estación Experimental del Zaidín (CSIC) Camino del Jueves s/n 18100 Armilla Granada Spain
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Ben Yahmed N, Carrere H, Marzouki MN, Smaali I. Enhancement of biogas production from Ulva sp. by using solid-state fermentation as biological pretreatment. ALGAL RES 2017. [DOI: 10.1016/j.algal.2017.09.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Manai I, Miladi B, El Mselmi A, Smaali I, Ben Hassen A, Hamdi M, Bouallagui H. Industrial textile effluent decolourization in stirred and static batch cultures of a new fungal strain Chaetomium globosum IMA1 KJ472923. J Environ Manage 2016; 170:8-14. [PMID: 26775156 DOI: 10.1016/j.jenvman.2015.12.038] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Revised: 12/27/2015] [Accepted: 12/30/2015] [Indexed: 06/05/2023]
Abstract
The treatment of an industrial textile effluent (ITE) was investigated by using a mono-culture of a novel fungal strain Chaetomium globosum IMA1. This filamentous fungus was selected based on its capacity for dye removal via the biodegradation mechanism. The respirometric analysis showed that C. globosum IMA1 was resistant to an indigo concentration up to 700 mg equivalent COD/L. The decolourization of the ITE by C. globosum was performed in static and stirred batch systems. The better lignin peroxidase (LiP), laccase and the manganese peroxidase (MnP) productions were 829.9 U/L, 83 U/L and 247.8 U/L, respectively since 3-5 days under a stirred condition. Therefore, the chemical oxygen demand (COD) and colors (OD620) removal yields reached 88.4% and 99.8%, respectively. Fourier transforms infrared spectroscopy (FTIR) analysis of the treated effluent showed that the decolourization was due to the degradation and the transformation of dye molecules. However, spectrophotometric examination showed that the complete dye removal was through fungal adsorption (8%), followed by degradation (92%).
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Affiliation(s)
- Imène Manai
- Université de Carthage, Lab Eco Tech Micro, INSAT, Tunis, Tunisia
| | - Baligh Miladi
- Université de Carthage, Lab Eco Tech Micro, INSAT, Tunis, Tunisia; Laboratoire de Biologie Moléculaire, Ecole de Biologie Industrielle, Cergy, France
| | - Abdellatif El Mselmi
- Laboratoire de Biologie Moléculaire, Ecole de Biologie Industrielle, Cergy, France
| | - Issam Smaali
- Université de Carthage, Lab Prot & Bioact Mol Engn INSAT, Tunis, Tunisia
| | - Aida Ben Hassen
- Laboratoire de valorisation énergétique des déchets (LVED), CRTEn, Tunisia
| | - Moktar Hamdi
- Université de Carthage, Lab Eco Tech Micro, INSAT, Tunis, Tunisia
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Jazzar S, Quesada-Medina J, Olivares-Carrillo P, Marzouki MN, Acién-Fernández FG, Fernández-Sevilla JM, Molina-Grima E, Smaali I. A whole biodiesel conversion process combining isolation, cultivation and in situ supercritical methanol transesterification of native microalgae. Bioresour Technol 2015; 190:281-288. [PMID: 25965253 DOI: 10.1016/j.biortech.2015.04.097] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Revised: 04/24/2015] [Accepted: 04/26/2015] [Indexed: 06/04/2023]
Abstract
A coupled process combining microalgae production with direct supercritical biodiesel conversion using a reduced number of operating steps is proposed in this work. Two newly isolated native microalgae strains, identified as Chlorella sp. and Nannochloris sp., were cultivated in both batch and continuous modes. Maximum productivities were achieved during continuous cultures with 318mg/lday and 256mg/lday for Chlorella sp. and Nannochloris sp., respectively. Microalgae were further characterized by determining their photosynthetic performance and nutrient removal efficiency. Biodiesel was produced by catalyst-free in situ supercritical methanol transesterification of wet unwashed algal biomass (75wt.% of moisture). Maximum biodiesel yields of 45.62wt.% and 21.79wt.% were reached for Chlorella sp. and Nannochloris sp., respectively. The analysis of polyunsaturated fatty acids of Chlorella sp. showed a decrease in their proportion when comparing conventional and supercritical transesterification processes (from 37.4% to 13.9%, respectively), thus improving the quality of the biodiesel.
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Affiliation(s)
- Souhir Jazzar
- LIP-MB Laboratory (LR11ES24), INSAT - University of Carthage, Tunisia
| | - Joaquín Quesada-Medina
- Department of Chemical Engineering, University of Murcia, Campus of Espinardo, E-30071 Murcia, Spain
| | - Pilar Olivares-Carrillo
- Department of Chemical Engineering, University of Murcia, Campus of Espinardo, E-30071 Murcia, Spain
| | | | | | | | - Emilio Molina-Grima
- Department of Chemical Engineering, University of Almería, E-04120 Almería, Spain
| | - Issam Smaali
- LIP-MB Laboratory (LR11ES24), INSAT - University of Carthage, Tunisia.
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Ahmed SBH, Sghaier RM, Guesmi F, Kaabi B, Mejri M, Attia H, Laouini D, Smaali I. Evaluation of antileishmanial, cytotoxic and antioxidant activities of essential oils extracted from plants issued from the leishmaniasis-endemic region of Sned (Tunisia). Nat Prod Res 2011; 25:1195-201. [PMID: 21740286 DOI: 10.1080/14786419.2010.534097] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
In this study, we tested 10 essential oils (EOs) extracted from 10 plants issued from Sned region (Tunisia) to evaluate both their leishmanicidal effects against Leishmania major and L. infantum, and their cytotoxicity against murine macrophage cell line RAW 264.7 (ATCC, TIB-71). The antioxidant activity was also monitored by the DDPH method, while the chemical composition of active EO was assessed by GC-MS analysis. The results showed that the EOs obtained from Thymus hirtus sp. algeriensis (rich on monoterpenoids, especially linalool at 17.62% and camphor at 13.82%) is significantly active against both L. major and L. infantum, whereas Ruta chalepensis EO (rich on 2-undecanone at 84.28%) is only active against L. infantum. Both oil extracts showed low cytotoxicity towards murine macrophages. The characteristic ratios (IC₈₀ Raw264.7 cells/IC₅₀ L. infantum and IC₈₀ Raw264.7 cells/IC₅₀ L. major) were, respectively, 2.7 and 1.57 for T. hirtus sp. algeriensis, and 1.34 and 0.19 for R. chalepensis. However, when measuring the antioxidant effects (DDPH method), the two latter EOs presented a moderate 2,2-diphenyl-2-picrylhydrazyl hydrate scavenging effects compared to EOs from Eucaliptus globulus, Pinus halepensis, Pituranthos tortuosus, Rosmarinus officinalis, Tetraclinis articulata or to BHT.
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Affiliation(s)
- S Ben Hadj Ahmed
- Département de Biologie, Faculté des Sciences de Gafsa, Campus Universitaire Zarroug-Gafsa 2112, Gafsa, Tunisia.
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Smaali I, Soussi A, Bouallagui H, Chaira N, Hamdi M, Marzouki M. Production of high-fructose syrup from date by-products in a packed bed bioreactor using a novel thermostable invertase fromAspergillus awamori. BIOCATAL BIOTRANSFOR 2011. [DOI: 10.3109/10242422.2011.615924] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Bouasker I, Khalfallah M, El Ouaer MA, Smaali I, Hani MA, Dziri C. Giant inflammatory fibrous polyp of the anal verge. Tunis Med 2010; 88:449-450. [PMID: 20517861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
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Smaali I, Rémond C, Skhiri Y, O'Donohue MJ. Biocatalytic conversion of wheat bran hydrolysate using an immobilized GH43 beta-xylosidase. Bioresour Technol 2009; 100:338-344. [PMID: 18674896 DOI: 10.1016/j.biortech.2008.06.041] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2008] [Revised: 06/10/2008] [Accepted: 06/11/2008] [Indexed: 05/26/2023]
Abstract
To investigate the concept of a xylosidase-based process for the continuous production of xylose from arabinoxylan-containing feedstocks, a beta-xylosidase from Bacillus halodurans C-125 was immobilized and deployed in packed bed reactor (PBR). Among the several immobilization methods tested, glutaraldehyde-mediated immobilization on chitosan was the best both in terms of immobilization and activity yields (91% and 72.9%, respectively). In batch experiments the immobilized enzyme hydrolyzed wheat bran hydrolysates quite efficiently, consuming nearly all xylobiose and xylotriose after 6h. Its reusability showed only a 50% decrease of its activity after 92h. Using the chitosan-immobilized beta-xylosidase in a PBR, xylose productivity was 7.2g xylose l(-1)h(-1) and the conversion factor was 0.55 (derived from initial xylose in the substrate). The operational stability of the PBR was good, because only 25% of productivity was lost after the treatment of three batches of substrate over a 72-h period.
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Affiliation(s)
- Issam Smaali
- Fractionnement des Agroressources et Emballage, URCA, UMR INRA 614, Reims Cedex 2, France.
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Smaali I, Bachraoui K, Joulek A, Selmi K, Boujnah MR. [Infectious endocarditis secondary to streptococcus bovis revealing adenomatous polyposis coli ]. Tunis Med 2008; 86:723-724. [PMID: 19472746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
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Smaali I, Rémond C, O'Donohue MJ. Expression in Escherichia coli and characterization of β-xylosidases GH39 and GH-43 from Bacillus halodurans C-125. Appl Microbiol Biotechnol 2006; 73:582-90. [PMID: 16896606 DOI: 10.1007/s00253-006-0512-5] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2006] [Revised: 05/17/2006] [Accepted: 05/17/2006] [Indexed: 10/24/2022]
Abstract
To develop xylosidases as tools for the hydrolysis of wheat bran arabinoxylans, two beta-xylosidases from Bacillus halodurans C-125 have been cloned and expressed in Escherichia coli. The recombinant (His)(6)-tagged enzymes, designated as XylBH39 and XylBH43, were efficiently purified using Ni(2+)-affinity chromatography. Determination of native molecular masses indicated that XylBH43 is dimeric in solution, whereas a similar analysis of XylBH39 did not allow differentiation between the dimeric and trimeric states. Both enzymes had similar pH and temperature optima (pH 7.5 and 55 degrees C for XylBH39 and pH 8 and 60 degrees C for XylBH43) and were relatively stable over the pH range of 3.5-8.5. In contrast, XylBH39 was more thermostable. At 60 degrees C, XylBH39 and XylBH43 displayed approximate half-life values of 2.40 and 0.05 h, respectively. The comparison of the ratio k (cat)/K (M) revealed that XylBH43 hydrolyzed p-nitrophenyl-beta-D: -xyloside more efficiently (4.6-fold) than XylBH39. Similarly, while XylBH43 was 18-fold less active on p-nitrophenyl-alpha-L: -arabinofuranoside, XylBH39 was essentially inactive on this substrate. Using either p-nitrophenyl-beta-D: -xyloside or xylotriose, XylBH39 performed transglycosylation, while xylobiose proved to be a poor substrate for both hydrolysis and transglycosylation. The use of XylBH39 and XylBH43 for the posttreatment of endoxylanase-generated wheat bran hydrolysates revealed that XylBH43 efficiently produced xylose monomers (385 microg/ml after 330 min incubation). Its activity was improved by the simultaneous deployment of an alpha-L: -arabinofuranosidase. Together, these enzymes were able to release 521 microg/ml of xylose after 330 min. This constitutes an approximate yield improvement of 35%.
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Affiliation(s)
- Issam Smaali
- Institut National de la Recherche Agronomique, UMR 614, 8 rue Gabriel Voisin, B.P. 316, 51688 Reims, Cedex 2, France
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Smaali I, Maugard T, Limam F, Legoy MD, Marzouki N. Efficient synthesis of gluco-oligosaccharides and alkyl-glucosides by transglycosylation activity of β-glucosidase from Sclerotinia sclerotiorum. World J Microbiol Biotechnol 2006. [DOI: 10.1007/s11274-006-9185-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Gargouri M, Smaali I, Maugard T, Legoy MD, Marzouki N. Fungus β-glycosidases: immobilization and use in alkyl-β-glycoside synthesis. ACTA ACUST UNITED AC 2004. [DOI: 10.1016/j.molcatb.2003.11.020] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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