Nova Biotechnologica et Chimica

Biosorption of Zn by dried biomass of Euglena gracilis from aqueous solutions

Linda Machalová — 2024-03-18

The aim of this work was to evaluate the possibility to utilize the dried biomass of Euglena gracilis var. bacillaris as a biosorbent applied for the removal of Zn from aqueous solutions. For these purposes, experiments involving solutions spiked by ⁶⁵ZnCl₂ were carried out under the conditions of batch systems. The prepared biosorbent in the form of dried biomass of E. gracilis (< 300 μm) was characterized in terms of the presence of functional groups (COOH, PO₃H₂, OH, and NH₂), the concentration of binding sites c_An and the value of pH_zpc = 6.6 using the modelling program ProtoFit. From the kinetics of Zn biosorption, it can be assumed that the Zn removal was a rapid process, in which the concentration equilibrium [Zn]_solution: [Zn]_biosorbent was stabilized in the first 5 min of interaction. In individual experiments, the effect of solution pH, initial biosorbent or Zn concentration were evaluated. Based on the MINEQL+ speciation modelling program, we predicted the decrease in the abundance of free Zn²⁺ cations in the presence of different concentrations of EDTA as a complexing agent in the solution. It was found that the Zn biosorption decreased linearly with the decreasing the proportion of Zn²⁺ in solution. The biosorption data expressed as equilibrium values of the remaining Zn concentration in solution C_eq (µmol.dm^-3) and equilibrium values of specific adsorption Q_eq (µmol.g^-1; d.w.) were well fitted to the Langmuir model of adsorption isotherm in comparison with the Freundlich model. The maximum adsorption capacity of the dried biomass of E. gracilis for the biosorption of Zn reached the value Q_max = 0.53 ± 0.05 mmol.g^-1or 34.7 ± 3.4 mg.g^-1 (d.w.), respectively.

Protective effect of ethanol extract of Coriolopsis aspera fruiting bodies against adjuvant-induced arthritis mice

Phuong-Nhung Thi Tran — 2024-01-30

Coriolopsis aspera is a medicinal mushroom that exerts several pharmacological and biological activities. However, the protective effect of the ethanol extract of C. aspera against arthritis has not been studied yet. In this study, we estimated some bioactive compounds in the ethanol extract of C. aspera fruiting bodies and used the extract with a dose of 400 mg.kg^-1 body weight or the reference drug Mobic (0.2 mg.kg^-1 body weight) to treat an adjuvant-induced arthritis model. Arthritis severity was determined via the changes in the diameters and volumes of hind paws, arthritic scores, total leukocyte count, ESR, biochemical parameters such as CRP and RF, as well as histological features of ankle joints. We found the presence of polyphenols and flavonoids with a high content (37.79 ± 0.88 mg GAE/g DW and 8.56 ± 0.37 mg QE/g DW, respectively) in the extract. Furthermore, the results showed that Freund’s complete adjuvant-treated mice exhibited a severe arthritic score and histological features, an increase in the diameters and volumes of hind paws, along with an elevation of leukocyte count, erythrocyte sediment rate, and biochemical parameters such as rheumatoid factor and C-reactive protein compared to normal mice. On the contrary, treatment with ethanol extract at a dose of 400 mg.kg^-1 body weight for 28 days exhibited a strong anti-arthritis effect and could improve all the testing parameters at the same efficacy as those of the reference drug (Mobic 0.2 mg.kg^-1 body weight). These findings suggest a potential application of the ethanol extract of C. aspera for arthritis treatment.

Fungicidal activities of chitosan-stabilized copper nanoparticles on Magnaporthe oryzae, Rhizoctonia solani, and Phytophthora capsica

Thi Kim Anh Nguyen — 2023-12-11

Pathogenic fungi are the most common causes of economic loss in crop production. Until now, synthetic fungicides are the most effective tools for management in agriculture, but they cause a severe impact on the environment as well as several side effects for human health. The use of synthetic fungicides is prohibited in organic agriculture; however, sulfur and copper fungicides are still permitted in organic farming. In this study, chitosan-stabilized copper chitosan nanoparticles (CS-CuNPs) were synthesized and characterized via UV-Vis analysis and scanning electron microscopy (SEM). Moreover, fungicidal activities of CS-CuNPs in the range of concentrations (00, 500, and 1000 mg/L) against several plant pathogenic fungi, including Magnaporthe oryzae, Rhizoctonia solani, and Phytophthora capsici, have been assessed via filamentous fugal growth inhibition. The results indicated that the size of CS-CuNPs ranged from 70 to 74 nm with the plasmon absorption peak at 600 nm, which implied the CS-CuNPs were successfully synthesized. Furthermore, CS-CuNPs effectively inhibited the growth of all three fungi at a concentration 1000 mg/L. Among the three species, Rhizoctonia solani was the most susceptible to CS-CuNPs, with the growth inhibitory effect at 100 mg/L. In conclusion, CS-CuNPs demonstrated a strong potential for the elimination of plant pathogenic fungi and further applications in agriculture.

Effect of exogenous dithiothreitol and lipoic acid on the content of photosynthetic pigments in oilseed rape Brassica napus L.

Dominika Dronzenková — 2024-01-30

We studied the effect of exogenous antioxidants dithiothreitol and lipoic acid on the contents of photosynthetic pigments, including total chlorophyll and carotenoids, in the leaves of regenerated shoots of the oilseed rape cultivars Mirakel, Lagonda and Menthal (Brasisca napus L.). The shoots were obtained from hypocotyl segments cultured for six weeks on in vitro regeneration media supplemented with dithiothreitol and lipoic acid at concentrations of 1 mg.dm^-3 and 10 mg.dm^-3, respectively. The application of DTT and LA resulted in a significant increase in the content of total chlorophyll and carotenoids, maintaining or increasing the Chl/carotenoids ratio in the cultivars Mirakel and Menthal. Unlike the cultivar Menthal, the frequency of explant regeneration significantly decreased in the cultivar Mirakel, which may be attributed to genotype-specific responses. Mirakel exhibited a higher frequency of regeneration under control conditions compared to Lagonda and Menthal. In the leaves of the cultivar Lagonda regenerated in the presence of DTT, there was a significant reduction in chlorophyll and carotenoid contents, along with a decrease in the Chl a/Chl b ratio, suggesting a conversion of Chl b to Chl a and a biphasic effect of DTT.