The Experts below are selected from a list of 1191 Experts worldwide ranked by ideXlab platform
Radhouane Kammoun - One of the best experts on this subject based on the ideXlab platform.
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Overproduction of Glucose Oxidase by Aspergillus tubingensis CTM 507 Randomly Obtained Mutants and Study of Its Insecticidal Activity against Ephestia kuehniella.
BioMed research international, 2020Co-Authors: Mouna Kriaa, Hanen Boukedi, Marwa Ben Rhouma, Yosri Ben Nasr, Slim Tounsi, Lotfi Mellouli, Radhouane KammounAbstract:In order to enhance the production of glucose oxidase (GOD), random mutagenesis of Aspergillus tubingensis CTM 507 was performed using the chemical and physical mutagens: nitric acid and UV irradiation, respectively. The majority of the isolated mutants showed good GOD production, but only some mutants presented a significant overproduction, as compared with the parent strain. The selected mutants (19 strains), showing an overproduction larger than 200%, are quite stable after three successive subcultures. Among these, six strains revealed an important improvement in submerged fermentation. The insecticidal activity of GOD produced by the wild and the selected mutant strains was evaluated against the third larval instars of E. kuehniella. Mutant strains U11, U12, U20, and U21, presenting the most important effect, displayed an LC50 value of 89.00, 88.51, 80.00, and 86.00 U/cm2, respectively, which was 1.5-fold more important than the wild strain (61 U/cm2). According to histopathology observations, the GOD enzyme showed approximately similar damage on the E. kuehniella midgut including rupture and disintegration of the epithelial layer and cellular vacuolization. The data supports, for the first time, the use of GOD as a pest control agent against E. kuehniella.
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producing Aspergillus tubingensis ctm507 glucose oxidase by solid state fermentation versus submerged fermentation process optimization and enzyme stability by an intermediary metabolite in relation with diauxic growth
Journal of Chemical Technology & Biotechnology, 2016Co-Authors: Mouna Kriaa, Radhouane KammounAbstract:BACKGROUND The variability of glucose oxidase (GOD) by Aspergillus tubingensis CTM507 in respect of titer under both submerged (SmF) and solid-state fermentation (SSF) was assessed in relation to growth and substrate consumption. L27 Taguchi experimental design was applied to determine optimum culture conditions for GOD production in SSF. RESULTS Kinetic results showed that fungal growth is a diauxic process which used glucose and gluconic acid as substrates, respectively, and that SmF is suitable for fungi growth. However, SSF led to higher GOD activity (170.59 U mL−1 against 43.73 U mL−1 by SmF). Moreover, GOD stability and liberation were related to the presence and levels of glucose, gluconic acid and to a lesser degree, lactose and arabinose. Optimization of culture media of multi-agro resources led to a final production yield of about 73103 U g−1 of substrates which corresponded to 10 and 84-fold higher than the preliminary SFF and SmF results, respectively. These conditions were validated experimentally and revealed an enhanced GOD yield of 74%. CONCLUSION These findings help an understanding of the phenomena of supremacy of SSF vs SmF to produce functional biomolecules. They also define an SSF process for an important enzyme production at low cost with interesting properties for industrial application. © 2015 Society of Chemical Industry
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Synergistic effect of Aspergillus tubingensis CTM 507 glucose oxidase in presence of ascorbic acid and alpha amylase on dough properties, baking quality and shelf life of bread.
Journal of food science and technology, 2015Co-Authors: Mouna Kriaa, Rabeb Ouhibi, Héla Graba, Souhail Besbes, Mohamed Jardak, Radhouane KammounAbstract:The impact of Aspergillus tubingensis glucose oxidase (GOD) in combination with α-amylase and ascorbic acid on dough properties, qualities and shelf life of bread was investigated. Regression models of alveograph and texture parameters of dough and bread were adjusted. Indeed, the mixture of GOD (44 %) and ascorbic acid (56 %) on flour containing basal improver showed its potential as a corrective action to get better functional and rheological properties of dough and bread texture. Furthermore, wheat flour containing basal additives and enriched with GOD (63.8 %), ascorbic acid (32 %) and α- amylase (4.2 %) led to high technological bread making parameters, to decrease the crumb firmness and chewiness and to improve elasticity, adhesion, cohesion and specific volume of bread. In addition to that, the optimized formulation addition significantly reduced water activity and therefore decreased bread susceptibility to microbial spoilage. These findings demonstrated that GOD could partially substitute not only ascorbic acid but also α-amylase. The generated models allowed to predict the behavior of wheat flour containing additives in the range of values tested and to define the additives formula that led to desired rheological and baking qualities of dough. This fact provides new perspectives to compensate flour quality deficiencies at the moment of selecting raw materials and technological parameters reducing the production costs and facilitating gluten free products development. Graphical abstractᅟ.
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Biocontrol of tomato plant diseases caused by Fusarium solani using a new isolated Aspergillus tubingensis CTM 507 glucose oxidase.
Comptes rendus biologies, 2015Co-Authors: Mouna Kriaa, Ines Hammami, Mouna Sahnoun, Manel Cheffi Azebou, Mohamed Ali Triki, Radhouane KammounAbstract:The present study focuses on the potential of glucose oxidase (GOD) as a promising biocontrol agent for fungal plant pathogens. In fact, a new GOD producing fungus was isolated and identified as an Aspergillus tubingensis. GOD (125 AU) has been found to inhibit Fusarium solani growth and spore production. Indeed, GOD caused the reduction of spores, the formation of chlamydospores, the induction of mycelial cords and the vacuolization of mycelium. In vivo assays, GOD acted as a curative treatment capable of protecting the tomato plants against F. solani diseases. In fact, the incidence was null in the curative treatment with GOD and it is around 45% for the preventive treatment. The optimization of media composition and culture conditions led to a 2.6-fold enhancement in enzyme activity, reaching 81.48U/mL. This study has demonstrated that GOD is a potent antifungal agent that could be used as a new biofungicide to protect plants from diseases.
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Purification, biochemical characterization and antifungal activity of a novel Aspergillus tubingensis glucose oxidase steady on broad range of pH and temperatures.
Bioprocess and biosystems engineering, 2015Co-Authors: Mouna Kriaa, Ines Hammami, Mouna Sahnoun, Manel Cheffi Azebou, Mohamed Ali Triki, Radhouane KammounAbstract:This study was carried out to evaluate the in vitro and in vivo antifungal efficiency of Aspergillus tubingensis CTM 507 glucose oxidase (GOD) against plant pathogenic fungi. GOD displayed a wide inhibitory spectrum toward different fungi at a concentration of 20 AU. The GOD had a strong inhibitor effect on mycelia growth and spore germination of Pythium ultimum. Interestingly, the GOD exhibited a potent in vivo antifungal effect against P. ultimum responsible for potato plants disease. The antifungal GOD was purified 13-fold with 27 % yield and a specific activity of 3435 U/mg. The relative molecular mass of the GOD was 180 kDa by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The GOD activity was optimum at pH 4.5 and 60 °C. It was found to be stable over a large pH range (3-9). It also displayed a marked thermostability with a 50-min half-life at 65 °C. The 10 residues of the N-terminal sequence of the purified GOD (S-K-G-S-A-V-T-T-P-D) showed no homology to the other reported GOD, identifying a novel GOD. FTIR spectroscopic analysis revealed the presence of C-O and C=O groups corresponding to a D-glucono-lactone. The findings indicated that GOD is the first A. tubingensis-produced fungicide ever reported to exhibit such promising biological properties. It could become a natural alternative to synthetic fungicides to control certain important plant microbial diseases.
Draženka Komes - One of the best experts on this subject based on the ideXlab platform.
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evaluation of microbial toxins trace elements and sensory properties of a high theabrownins instant pu erh tea produced using Aspergillus tubingensis via submerged fermentation
International Journal of Food Science and Technology, 2019Co-Authors: Qiuping Wang, Yusuf Chisti, Jiashun Gong, Sarote Sirisansaneeyakul, Bojan Sarkanj, Jasna Jurasovic, Michael Sulyok, Draženka KomesAbstract:Theabrownins (TB) are polymeric phenolic compounds associated with the multiple bioactivities of Pu‐erh tea, a post‐fermented Chinese dark tea. High‐TB instant Pu‐erh tea was produced via a novel submerged fermentation (SF) using Aspergillus tubingensis and compared with samples produced commercially via the conventional solid‐state fermentation (SSF). Viable microorganisms and microbial toxins, especially aflatoxins B₁, G₁, B₂, G₂, cyclopiazonic acid, fumonisins B₁, B₂, B₃ and ochratoxin A, were below the detection limit in all samples. Fewer microbial metabolites were found in SF instant tea compared with the SSF teas. Based on an adult consuming 1 g of instant Pu‐erh tea daily, the dietary intake of investigated elements was below the safe limits recommended by various authorities. Tasters viewed the instant tea infusions as very mild, smooth, mellow and full. This suggested that submerged fermentation using A. tubingensis offers a speedy and safe alternative to commercial production of instant Pu‐erh tea.
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physicochemical properties and biological activities of a high theabrownins instant pu erh tea produced using Aspergillus tubingensis
Lwt - Food Science and Technology, 2018Co-Authors: Qiuping Wang, Ana Belscakcvitanovic, Ksenija Durgo, Yusuf Chisti, Jiashun Gong, Sarote Sirisansaneeyakul, Draženka KomesAbstract:Abstract High-theabrownins (TB) instant Pu-erh tea was produced via a novel submerged fermentation (SF) by Aspergillus tubingensis and compared with samples produced commercially via the conventional solid-state fermentation (SSF). All tea samples were assessed for physicochemical properties and biological activities (cytotoxicity toward cancer cells; antioxidant capacity). TB content of SF tea was nearly 4-fold compared to SSF teas. SF instant Pu-erh tea had significantly higher levels of theabrownins, total polyphenols, total flavonoids, caffeine and theobromine compared to the SSF ripe tea, but had significantly lower levels of gallic acid, total catechins, epicatechin, epicatechin gallate, theaflavins, thearubigins, amino acids, total carbohydrate and polysaccharides. The free radical scavenging ability of SF-produced tea was lower than of the teas made via SSF. At suitable combinations of concentration and contact time, the instant Pu-erh tea had anticancer and antioxidative effects in vitro. The cytotoxic effect and the intracellular reactive oxygen species scavenging capacity of SF tea was mainly associated with theabrownins.
Mouna Kriaa - One of the best experts on this subject based on the ideXlab platform.
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Overproduction of Glucose Oxidase by Aspergillus tubingensis CTM 507 Randomly Obtained Mutants and Study of Its Insecticidal Activity against Ephestia kuehniella.
BioMed research international, 2020Co-Authors: Mouna Kriaa, Hanen Boukedi, Marwa Ben Rhouma, Yosri Ben Nasr, Slim Tounsi, Lotfi Mellouli, Radhouane KammounAbstract:In order to enhance the production of glucose oxidase (GOD), random mutagenesis of Aspergillus tubingensis CTM 507 was performed using the chemical and physical mutagens: nitric acid and UV irradiation, respectively. The majority of the isolated mutants showed good GOD production, but only some mutants presented a significant overproduction, as compared with the parent strain. The selected mutants (19 strains), showing an overproduction larger than 200%, are quite stable after three successive subcultures. Among these, six strains revealed an important improvement in submerged fermentation. The insecticidal activity of GOD produced by the wild and the selected mutant strains was evaluated against the third larval instars of E. kuehniella. Mutant strains U11, U12, U20, and U21, presenting the most important effect, displayed an LC50 value of 89.00, 88.51, 80.00, and 86.00 U/cm2, respectively, which was 1.5-fold more important than the wild strain (61 U/cm2). According to histopathology observations, the GOD enzyme showed approximately similar damage on the E. kuehniella midgut including rupture and disintegration of the epithelial layer and cellular vacuolization. The data supports, for the first time, the use of GOD as a pest control agent against E. kuehniella.
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producing Aspergillus tubingensis ctm507 glucose oxidase by solid state fermentation versus submerged fermentation process optimization and enzyme stability by an intermediary metabolite in relation with diauxic growth
Journal of Chemical Technology & Biotechnology, 2016Co-Authors: Mouna Kriaa, Radhouane KammounAbstract:BACKGROUND The variability of glucose oxidase (GOD) by Aspergillus tubingensis CTM507 in respect of titer under both submerged (SmF) and solid-state fermentation (SSF) was assessed in relation to growth and substrate consumption. L27 Taguchi experimental design was applied to determine optimum culture conditions for GOD production in SSF. RESULTS Kinetic results showed that fungal growth is a diauxic process which used glucose and gluconic acid as substrates, respectively, and that SmF is suitable for fungi growth. However, SSF led to higher GOD activity (170.59 U mL−1 against 43.73 U mL−1 by SmF). Moreover, GOD stability and liberation were related to the presence and levels of glucose, gluconic acid and to a lesser degree, lactose and arabinose. Optimization of culture media of multi-agro resources led to a final production yield of about 73103 U g−1 of substrates which corresponded to 10 and 84-fold higher than the preliminary SFF and SmF results, respectively. These conditions were validated experimentally and revealed an enhanced GOD yield of 74%. CONCLUSION These findings help an understanding of the phenomena of supremacy of SSF vs SmF to produce functional biomolecules. They also define an SSF process for an important enzyme production at low cost with interesting properties for industrial application. © 2015 Society of Chemical Industry
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Synergistic effect of Aspergillus tubingensis CTM 507 glucose oxidase in presence of ascorbic acid and alpha amylase on dough properties, baking quality and shelf life of bread.
Journal of food science and technology, 2015Co-Authors: Mouna Kriaa, Rabeb Ouhibi, Héla Graba, Souhail Besbes, Mohamed Jardak, Radhouane KammounAbstract:The impact of Aspergillus tubingensis glucose oxidase (GOD) in combination with α-amylase and ascorbic acid on dough properties, qualities and shelf life of bread was investigated. Regression models of alveograph and texture parameters of dough and bread were adjusted. Indeed, the mixture of GOD (44 %) and ascorbic acid (56 %) on flour containing basal improver showed its potential as a corrective action to get better functional and rheological properties of dough and bread texture. Furthermore, wheat flour containing basal additives and enriched with GOD (63.8 %), ascorbic acid (32 %) and α- amylase (4.2 %) led to high technological bread making parameters, to decrease the crumb firmness and chewiness and to improve elasticity, adhesion, cohesion and specific volume of bread. In addition to that, the optimized formulation addition significantly reduced water activity and therefore decreased bread susceptibility to microbial spoilage. These findings demonstrated that GOD could partially substitute not only ascorbic acid but also α-amylase. The generated models allowed to predict the behavior of wheat flour containing additives in the range of values tested and to define the additives formula that led to desired rheological and baking qualities of dough. This fact provides new perspectives to compensate flour quality deficiencies at the moment of selecting raw materials and technological parameters reducing the production costs and facilitating gluten free products development. Graphical abstractᅟ.
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Biocontrol of tomato plant diseases caused by Fusarium solani using a new isolated Aspergillus tubingensis CTM 507 glucose oxidase.
Comptes rendus biologies, 2015Co-Authors: Mouna Kriaa, Ines Hammami, Mouna Sahnoun, Manel Cheffi Azebou, Mohamed Ali Triki, Radhouane KammounAbstract:The present study focuses on the potential of glucose oxidase (GOD) as a promising biocontrol agent for fungal plant pathogens. In fact, a new GOD producing fungus was isolated and identified as an Aspergillus tubingensis. GOD (125 AU) has been found to inhibit Fusarium solani growth and spore production. Indeed, GOD caused the reduction of spores, the formation of chlamydospores, the induction of mycelial cords and the vacuolization of mycelium. In vivo assays, GOD acted as a curative treatment capable of protecting the tomato plants against F. solani diseases. In fact, the incidence was null in the curative treatment with GOD and it is around 45% for the preventive treatment. The optimization of media composition and culture conditions led to a 2.6-fold enhancement in enzyme activity, reaching 81.48U/mL. This study has demonstrated that GOD is a potent antifungal agent that could be used as a new biofungicide to protect plants from diseases.
-
Purification, biochemical characterization and antifungal activity of a novel Aspergillus tubingensis glucose oxidase steady on broad range of pH and temperatures.
Bioprocess and biosystems engineering, 2015Co-Authors: Mouna Kriaa, Ines Hammami, Mouna Sahnoun, Manel Cheffi Azebou, Mohamed Ali Triki, Radhouane KammounAbstract:This study was carried out to evaluate the in vitro and in vivo antifungal efficiency of Aspergillus tubingensis CTM 507 glucose oxidase (GOD) against plant pathogenic fungi. GOD displayed a wide inhibitory spectrum toward different fungi at a concentration of 20 AU. The GOD had a strong inhibitor effect on mycelia growth and spore germination of Pythium ultimum. Interestingly, the GOD exhibited a potent in vivo antifungal effect against P. ultimum responsible for potato plants disease. The antifungal GOD was purified 13-fold with 27 % yield and a specific activity of 3435 U/mg. The relative molecular mass of the GOD was 180 kDa by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The GOD activity was optimum at pH 4.5 and 60 °C. It was found to be stable over a large pH range (3-9). It also displayed a marked thermostability with a 50-min half-life at 65 °C. The 10 residues of the N-terminal sequence of the purified GOD (S-K-G-S-A-V-T-T-P-D) showed no homology to the other reported GOD, identifying a novel GOD. FTIR spectroscopic analysis revealed the presence of C-O and C=O groups corresponding to a D-glucono-lactone. The findings indicated that GOD is the first A. tubingensis-produced fungicide ever reported to exhibit such promising biological properties. It could become a natural alternative to synthetic fungicides to control certain important plant microbial diseases.
Qiuping Wang - One of the best experts on this subject based on the ideXlab platform.
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evaluation of microbial toxins trace elements and sensory properties of a high theabrownins instant pu erh tea produced using Aspergillus tubingensis via submerged fermentation
International Journal of Food Science and Technology, 2019Co-Authors: Qiuping Wang, Yusuf Chisti, Jiashun Gong, Sarote Sirisansaneeyakul, Bojan Sarkanj, Jasna Jurasovic, Michael Sulyok, Draženka KomesAbstract:Theabrownins (TB) are polymeric phenolic compounds associated with the multiple bioactivities of Pu‐erh tea, a post‐fermented Chinese dark tea. High‐TB instant Pu‐erh tea was produced via a novel submerged fermentation (SF) using Aspergillus tubingensis and compared with samples produced commercially via the conventional solid‐state fermentation (SSF). Viable microorganisms and microbial toxins, especially aflatoxins B₁, G₁, B₂, G₂, cyclopiazonic acid, fumonisins B₁, B₂, B₃ and ochratoxin A, were below the detection limit in all samples. Fewer microbial metabolites were found in SF instant tea compared with the SSF teas. Based on an adult consuming 1 g of instant Pu‐erh tea daily, the dietary intake of investigated elements was below the safe limits recommended by various authorities. Tasters viewed the instant tea infusions as very mild, smooth, mellow and full. This suggested that submerged fermentation using A. tubingensis offers a speedy and safe alternative to commercial production of instant Pu‐erh tea.
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physicochemical properties and biological activities of a high theabrownins instant pu erh tea produced using Aspergillus tubingensis
Lwt - Food Science and Technology, 2018Co-Authors: Qiuping Wang, Ana Belscakcvitanovic, Ksenija Durgo, Yusuf Chisti, Jiashun Gong, Sarote Sirisansaneeyakul, Draženka KomesAbstract:Abstract High-theabrownins (TB) instant Pu-erh tea was produced via a novel submerged fermentation (SF) by Aspergillus tubingensis and compared with samples produced commercially via the conventional solid-state fermentation (SSF). All tea samples were assessed for physicochemical properties and biological activities (cytotoxicity toward cancer cells; antioxidant capacity). TB content of SF tea was nearly 4-fold compared to SSF teas. SF instant Pu-erh tea had significantly higher levels of theabrownins, total polyphenols, total flavonoids, caffeine and theobromine compared to the SSF ripe tea, but had significantly lower levels of gallic acid, total catechins, epicatechin, epicatechin gallate, theaflavins, thearubigins, amino acids, total carbohydrate and polysaccharides. The free radical scavenging ability of SF-produced tea was lower than of the teas made via SSF. At suitable combinations of concentration and contact time, the instant Pu-erh tea had anticancer and antioxidative effects in vitro. The cytotoxic effect and the intracellular reactive oxygen species scavenging capacity of SF tea was mainly associated with theabrownins.
Yusuf Chisti - One of the best experts on this subject based on the ideXlab platform.
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evaluation of microbial toxins trace elements and sensory properties of a high theabrownins instant pu erh tea produced using Aspergillus tubingensis via submerged fermentation
International Journal of Food Science and Technology, 2019Co-Authors: Qiuping Wang, Yusuf Chisti, Jiashun Gong, Sarote Sirisansaneeyakul, Bojan Sarkanj, Jasna Jurasovic, Michael Sulyok, Draženka KomesAbstract:Theabrownins (TB) are polymeric phenolic compounds associated with the multiple bioactivities of Pu‐erh tea, a post‐fermented Chinese dark tea. High‐TB instant Pu‐erh tea was produced via a novel submerged fermentation (SF) using Aspergillus tubingensis and compared with samples produced commercially via the conventional solid‐state fermentation (SSF). Viable microorganisms and microbial toxins, especially aflatoxins B₁, G₁, B₂, G₂, cyclopiazonic acid, fumonisins B₁, B₂, B₃ and ochratoxin A, were below the detection limit in all samples. Fewer microbial metabolites were found in SF instant tea compared with the SSF teas. Based on an adult consuming 1 g of instant Pu‐erh tea daily, the dietary intake of investigated elements was below the safe limits recommended by various authorities. Tasters viewed the instant tea infusions as very mild, smooth, mellow and full. This suggested that submerged fermentation using A. tubingensis offers a speedy and safe alternative to commercial production of instant Pu‐erh tea.
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physicochemical properties and biological activities of a high theabrownins instant pu erh tea produced using Aspergillus tubingensis
Lwt - Food Science and Technology, 2018Co-Authors: Qiuping Wang, Ana Belscakcvitanovic, Ksenija Durgo, Yusuf Chisti, Jiashun Gong, Sarote Sirisansaneeyakul, Draženka KomesAbstract:Abstract High-theabrownins (TB) instant Pu-erh tea was produced via a novel submerged fermentation (SF) by Aspergillus tubingensis and compared with samples produced commercially via the conventional solid-state fermentation (SSF). All tea samples were assessed for physicochemical properties and biological activities (cytotoxicity toward cancer cells; antioxidant capacity). TB content of SF tea was nearly 4-fold compared to SSF teas. SF instant Pu-erh tea had significantly higher levels of theabrownins, total polyphenols, total flavonoids, caffeine and theobromine compared to the SSF ripe tea, but had significantly lower levels of gallic acid, total catechins, epicatechin, epicatechin gallate, theaflavins, thearubigins, amino acids, total carbohydrate and polysaccharides. The free radical scavenging ability of SF-produced tea was lower than of the teas made via SSF. At suitable combinations of concentration and contact time, the instant Pu-erh tea had anticancer and antioxidative effects in vitro. The cytotoxic effect and the intracellular reactive oxygen species scavenging capacity of SF tea was mainly associated with theabrownins.
