Optimization of extracellular catalase production from Aspergillus phoenicis K30 by a linear regression method using date flour as single carbon source and purification of the enzyme

Aspergillus phoenicis K30 is the selected mutant which produces an amount of extracellular catalase. To amplify the extracellular catalase production by the strain, a fermentation optimization was performed. To select the factors affecting the production, nine active variables (factors) consisting of 12 experiments were analyzed by Plackett-Burman design. Each variable was tested at two levels, a higher and a lower level. The studies of the effect of each variable and the establishment of a correlation between the response of enzyme activity and variables revealed that the link is a multiple linear regression form. The optimization was carried out through a simplex algorithm. The amount of extracellular catalase produced by the strain in the optimized medium was about four times higher than that obtained in non optimized medium corresponding to 3820 mg/L of extracellular proteins including 59500 U/L of extracellular catalase activity after 96 h of fermentation. The steps of purification were allowed to improve enzyme activity by 305-fold. From an analytical gel electrophoresis under native conditions, an apparent molecular mass of 158 kDa was determined suggesting that the enzyme is a homodimer. The isoelectric point of the protein was found to be 5 ± 0.1 as determined by a Pharmacia Phast-system.Keywords: Aspergillus phoenicis, extracellular catalase purification, dates flour, optimization, multiple linear regression.African Journal of Biotechnology Vol. 12(19), pp. 2646-265

Decommissioned dates: chemical composition and fermentation substrate for the production of extracellular catalase by an Aspergillus phoenicis mutant

peer reviewedThe recovery of dates downgraded as a fermentation medium for the production of extracellular catalase by Aspergillus phoenicis K30 was studied. Analysis of the chemical composition of pulp and kernel flour of dates showed that the pulp had a considerably greater carbohydrate content compared to the kernel (84 vs 2.93% respectively). However, the kernel flour was richer in nitrogen (0.68% vs 0.34), mineral elements (3.63 vs 1.28%) and in essential fatty acids C18: 2 vs C18: 3 than the pulp flour. The soluble extract of the date flour showed that sugars solubilised at 90% consisted of sucrose, fructose and glucose. Therefore, this extract, being an important source of carbon and energy, was used in the current study as a fermentation medium (after supplementation with 20% of corn steep) for the production of extracellular catalase by A. Phoenicis K30. During the course of this fermentation, the biomass was estimated at 18.6 g / L after 72 h of culture, while the maximum concentration of extracellular catalase (47.5 U / ml) was reached at 96 h of fermentation. The mycelium obtained in pellet form is suitable for industrial exploitation of this process

Chlorpyrifos-induced oxidative stress and tissue damage in the liver, kidney, brain and fetus in pregnant rats: the protective role of the butanolic extract of **Paronychia argentea** L.

Objective : Toxicity of pesticides is thought to be due to reactive oxygen species (ROS). Due to their antioxidant property, polyphenols in plant extracts may afford protection from pesticide toxicity. In the present study, we evaluated the protective effect of a butanolic extract of Paronychia argentea L. against toxicity caused by the organophosphorus pesticide, chloropyriphos ethyl (CE). Materials and Methods: Pregnant albino Wistar rats were used. Pesticide and plant extract were administered daily by oral gavage from the 6 th to the 15 th day of gestation. Plasma and tissue malondialdehyde (MDA), blood reduced glutathione (GSH) and erythrocyte superoxide dismutase (SOD) activities were estimated. MDA levels were estimated in plasma and different organs (liver, kidney, brain, placenta and in the fetuses and their livers) as an indicator of lipid peroxydation (LPO). Results: The data showed a significant increase in plasma and tissue LPO levels in animals treated with the pesticide while the effect was attenuated by the plant extract (CE-ex). Also, CE caused a significant decrease in antioxidant enzyme activity and this effect was partially reversed in groups treated with the plant extract. The pesticide induced embryotoxicity and resulted in resorption, fetal death and a reduced implant number. Conclusion : It can be concluded that CE can lead to an increase in LPO production in adult and fetal tissues, while treatment with the plant extract leads to protection against CE toxicity. The decrease in LPO levels and the increase in GSH and SOD enzyme activities after treatment with the plant extract revealed its antioxidant property

The protective effect of Chrysanthemum fantanesii extract, vitamin E and C on sodium valproate-induced embryotoxicity in pregnant mice

investigated the ability of butanolic extract from leaves of Chrysanthemum fantanesii, vitamin E and C to modulate VPA-induced toxicity and oxidation damage in maternal and fetal tissues in mice. Plant extract, VPA and vitamins were administered orally to pregnant mice from the 6 to 17th day of gestation. Animals received plant extract (200 mg/kg per day), vitamin E (100 mg/kg per day) and vitamin C (8.3 mg/kg per day) with an oral administration of VPA (400 mg /kg per day) under the same conditions. On day 18 of gestation pregnant mice were sacrificed, fetuses, placenta and maternal tissues were removed, homogenized and used for the determination of lipid peroxidation rates (LPO) using thiobarbituric acid reactive substance (TBARS) method. Embryotoxicity was assessed by counting the number of implants, live and dead fetuses, and resumptions. The fetuses were observed for malformation including neural tube defect (Exencephaly), open eyes and skeletal malformation. The results show clearly that there is a positive correlation between the increase in LPO and congenital malformation. Plant extract, vitamin E and C caused partial decrease of embryo toxicity and congenital malformation induced by VPA in mic

Improved Quantum Chaotic Animal Migration Optimization Algorithm for QoS Multicast Routing Problem

Part 2: Evolutionary ComputationInternational audienceIn recent years, we are witnessing the spread of many and various modern real-time applications implemented on computer networks such as video conferencing, distance education, online games, and video streaming. These applications require the high quality of different network resources such as bandwidth, delay, jitter, and packet loss rate. In this paper, we propose an improved quantum chaotic animal migration optimization algorithm to solve the multicast routing problem (Multi-Constrained Least Cost MCLC). We used a quantum representation of the solutions that allow the use of the original AMO version without discretization, as well as improving AMO by introducing chaotic map to determine the random numbers. These two contributions improve the diversification and intensification of the algorithm. The simulation results show that our proposed algorithm has a good scalability and efficiency compared with other existing algorithms in the literature