9 research outputs found
Antioxidant and antimicrobial potentials of Retama Sphaerocarpa.
No full textInternational audienceThe present work studies the antioxidant activities and antimicrobial properties of the aerial part of Retama sphaerocarpa. The secondary metabolites (polyphenols) were extracted using different solvents: chloroform, ethyl acetate and n-butanol. In each fraction, total polyphenols and flavonoids were respectively quantified using Folin-Ciocalteu test and aluminium chloride colorimetric method. The concentration of polyphenols was higher in the chloroform extract (121.4 ± 0.3 mg GAE/g), than in n-butanol extract (111.7 ± 0.1 mg GAE/g) and ethyl acetate extract (73.0 ± 0.4 mgGAE/g). The evaluation of flavonoids content also showed a high value of flavonoid in chloroform extract (20.9 ± 0.2 mg QE /g DM), whereas the ethyl acetate and the n-butanol extracts of Retama sphaerocarpa leaves contained similar quantity of flavonoids with 16.5± 0.8 mg QE /g DM and 15.3± 0.7 mg QE /g DM, respectively. The obtained extracts of R. sphaerocarpa were also evaluated for their antioxidant activities using DPPH radical-scavenging method. The three extracts (i.e. chloroform, ethyl acetate and n-butanol extracts) showed very high free radical scavenging activity: 73 ± 0.8, 75.6 ± 1.9 and 81.5 ± 0.3 (%), respectively. We also investigated the antimicrobial activities of the three extracts using the disc diffusion method. Each of the three extracts were active against Bacillus sp
Phytochemical analysis, antioxidant and antimicrobial activities of leaves and flowers ethyl acetate and n-butanol fractions from an Algerian endemic plant Calycotome spinosa (L.) Link
No full textKinetic models and parameters estimation study of biomass and ethanol production from inulin by Pichia caribbica (KC977491)
No full textKinetic models and parameters estimation study of biomass and ethanol production from inulin by Pichia caribbica (KC977491)
Get PDFThe growth kinetics and modeling of ethanol production from inulin by Pichia caribbica (KC977491) were studied in a batch system. Unstructured models were proposed using the logistic equation for growth, the Luedeking-Piret equation for ethanol production and modified Leudeking-Piret model for substrate consumption. Kinetic parameters (X0, μm, m, n, p and q) were determined by nonlinear regression, using Levenberg-Marquart method implemented in a Mathcad program. Since the production of ethanol was associated with P. caribbica cell growth, a good agreement between model predictions and experimental data was obtained. Indeed, significant R2 values of 0.91, 0.96, and 0.95 were observed for biomass, ethanol production and substrate consumption, respectively. Furthermore, analysis of variance (ANOVA) was also used to validate the proposed models. According to the obtained results, the predicted kinetic values and experimental data agreed well . Finally, it is possible to predict the development of P. caribbica using these models.Key words: Pichia caribbica, inulin, bioethanol, numerical simulation
Optimization of Baker’s Yeast Production on Date Extract Using Response Surface Methodology (RSM)
No full textThis work aims to study the production of the biomass of S. cerevisiae on an optimized medium using date extract as the only carbon source in order to obtain a good yield of the biomass. The biomass production was carried out according to the central composite experimental design (CCD) as a response surface methodology using Minitab 16 software. Indeed, under optimal biomass production conditions, temperature (32.9 °C), pH (5.35) and the total reducing sugar extracted from dates (70.93 g/L), S. cerevisiae produced 40 g/L of their biomass in an Erlenmeyer after only 16 h of fermentation. The kinetic performance of the S. cerevisiae strain was investigated with three unstructured models i.e., Monod, Verhulst, and Tessier. The conformity of the experimental data fitted showed a good consistency with Monod and Tessier models with R2 = 0.945 and 0.979, respectively. An excellent adequacy was noted in the case of the Verhulst model (R2 = 0.981). The values of kinetic parameters (Ks, Xm, μm, p and q) calculated by the Excel software, confirmed that Monod and Verhulst were suitable models, in contrast, the Tessier model was inappropriately fitted with the experimental data due to the illogical value of Ks (−9.434). The profiles prediction of the biomass production with the Verhulst model, and that of the substrate consumption using Leudeking Piret model over time, demonstrated a good agreement between the simulation models and the experimental data
Effect of Zinc on the Growth and the Antioxidant System of Lens Culinaris Cultivated on Agar Medium
No full textThis study aimed to analyze the impact of Zn on the growth and the antioxidant response of Lens culinaris. For this purpose, the seeds were germinated for 6 days in an MS/2 culture medium with different Zn concentrations. Malondialdehyde (MDA), total protein contents, and antioxidant enzymes activities were measured in both parts of the plant by spectrometry. The results showed that from the Zn concentration of 250 µM, the growth of lentils is inversely proportional to the concentration of Zn in the culture medium. The variations in the level of MDA are not very significant, but at 10 000 μM of Zn in the medium, the level becomes very important, whilst the total protein content decreased. Besides, the evaluation of enzymatic activities indicated that the decline of peroxidase (POD) is concomitant with the increase in glutathione peroxidase (GPx) and that glutathione S-transferase (GST), as well as catalase (CAT) reach their maximum activities at 10 000 µM and 3000 µM of Zn in upper parts and roots, respectively. These findings revealed that MDA is a real indicator of oxidative stress in Lens culinaris and that this plant is tolerant to the presence of Zn in the culture medium by developing a powerful antioxidant system, but beyond a certain concentration its antioxidant system becomes ineffective and the plant enters a stress state
Box-Behnken design optimization of xylanase and cellulase production by Aspergillus fumigatus on Stipa tenacissima biomass
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Production of a halotolerant endo‐1,4‐β‐glucanase by a newly isolated Bacillus velezensis H1 on olive mill wastes without pretreatment: purification and characterization of the enzyme
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A new record of Agaricus litoralis, a rare edible macro-fungus from Eastern Algeria
Get PDFA rare edible macro-fungus of phylum Basidiomycota belonging to the genus Agaricus (Agaricales, Agaricomycetes) was collected at the forest of Djebel el Ouahech of Constantine region in the eastern of Algeria and was identified as Agaricus litoralis using morphological and molecular Data. The species Agaricus litoralis is reported for the first time in Algeria
