Zeitschrift für Bioverarbeitung und Biotechnik

The present study evaluated the influence of variables involved in the drying process by atomization on the physico-chemical properties of umbu powder. The process was carried out using a laboratory scale atomizer with DE 15 maltodextrin as the carrier agent. Seventeen assays were performed according to a central composite rotational design. The independent variables were drying air temperature, mass feeding flow, and carrier agent concentration. The analyzed responses were water activity, moisture, hygroscopicity, process yield, and retention of phenolic compounds (RPC) in the final product. Drying air temperature negatively affected water activity and moisture content, i.e., higher applied temperatures led to lower water activity and moisture content in atomized umbu. However, the effects of the linear, quadratic, and interaction factors were not statistically significant over hygroscopicity and process yield at 95% level of statistical significance; therefore, it was not possible to generate a model. The RPC was influenced by the mass feeding flow and carrier agent concentration; the use of faster flows and higher concentrations of maltodextrin presented a final product with higher RPC. Based on the analysis of response surface graphs, an assay was selected and physically characterized: apparent density of 0.61 g/mL and percentage of solubility of 80.28%. Atomized umbu particles showed uniform size and formed numerous small pellets with spherical shape and predominantly rough surface.

Due to the effective antimicrobial properties of silver nanoparticles (Ag-NPs), these particles are receiving an extensive interest for applying in wide range of consumer products and water purification systems. Entering the Agbased material in wastewater system can influence the biological cycle such as nitrogen. Denitrification as a part of nitrogen cycle is an effective biological process in wastewater systems which can be affected by Ag-NPs. The objective of this research was to study the impact of Ag-NPs on aerobic nitrate reduction. We showed that Rhizobium sp and Azotobacter sp isolates were able to reduce nitrate aerobically. Adding 0.2 ppm of Ag-NPs in culture medium of Azotobacter PHB⁺ enhanced the nitrate reduction activity about 20% and Ag-NPs at this concentration has no significant effect on the nitrate reduction activity of periplasmic extracts of the selected isolates in aerobic conditions. Thus, it seems that entering certain concentration of Ag-NPs in environments has no significant impact on microbial aerobic denitrification as a certain part of nitrogen cycle.

The applications of starch in food systems are primarily governed by its gelatinization, pasting, solubility, swelling and digestibility properties. To select the appropriate variety starch for end-use suitability, thermal, pasting and gel textural properties of nine starches were determined. Commercial grade wheat starch, corn starch, potato starch, sweet potato starch, cassava starch, mung bean starch, pea starch, amylose from potato, and amylopectin from waxy corn were used in the research aim to the industry end-use. Wheat starch showed the lowest transition temperatures (the onset temperature, T_o and the peak temperature, T_p). Sweet potato starch and cassava starch showed the highest transition temperatures and the lowest enthalpy changes. Mung bean starch showed the slowest transition speed. Tuber and root starches showed higher pasting temperatures, peak viscosity, final viscosity, breakdown viscosity, setback viscosity, and lower adhesiveness. Legume starches showed the highest hardness values. Person correlations and a principal component analysis showed that the transition temperatures were negatively correlated with enthalpy change (p<0.01). Peak viscosity, final viscosity, breakdown viscosity and setback viscosity were positively correlated with each other, but negatively correlated with adhesiveness. The hardness was positively correlated with springiness (r=0.830, p<0.01), and the cohesiveness was positively correlated with enthalpy change.

Gluconoacetobacter hansenii CGMCC3917 (M₄₃₈), isolated from inoculums of strain J₂ treated by high hydrostatic pressure, has strong ability of producing cellulose as more than three times as that of its initial strain J₂. In this paper, in order to further study the effects of high hydrostatic pressure treatment on characterizations of strain J₂ on the basis of previous study, properties of these two strains were examined and compared. The results indicated that the mutant strain M₄₃₈ and its initial strain J₂ had different Phenotypic Characterizations in liquid seed medium. The fermentation parameters showed that cell growth rate of strain M₄₃₈ was relatively higher than that of strain J₂, namely, residual sugar, residual nitrogen and acidity of strain M₄₃₈ were less than that of strain J₂. Furthermore, water holding capacity (WHC) and water release rate (WRR) of bacterial cellulose (BC) membranes produced by M₄₃₈ were both better than those of BC membranes produced by J₂. However, SEM imagines suggested that there was no evidence difference in microstructure of BC membranes. Additionally, FT-IR also showed no difference between BC membranes produced by strain M₄₃₈ and its initial strain J₂.

Great amounts of carbon dioxide generated by Pseudomonas denitrificans during high aerobic vitamin B₁₂ fermentation, while the influence of CO₂ concentration on vitamin B₁₂ production remains unclear. In this paper, we present parallel experiments to investigate various levels of inlet CO₂ fractions on the physiological metabolism of P. denitrificans in laboratory scale fermentation. The results demonstrated that the oxygen transfer rate, cell growth and glucose consumption were inhibited with CO₂ fraction elevated from 0.03% to 8.86 ± 0.24%, while the most exciting results showed that the specific vitamin B₁₂ production rate and the yield to glucose were greatly stimulated when dissolved CO₂ increased to 8.86 ± 0.24%. Therefore, the optimal exhausted CO₂ fraction control strategy in 120 m³ fermenter was established. With the exhaust CO₂ concentration was well controlled at 7.5 ± 0.25% on-line, vitamin B₁₂ production greatly improved to 223.7 ± 3.7 mg/L, which was 11.2% higher than that of control. This strategy was proved to be significant necessary and effective for successfully scale up optimization in industrial vitamin B₁₂ fermentation.

The leaf methanolic extract scavenged each gas NO and DPPH radical with a dose dependent manner. However the pet ether fraction of root was found to possess highest effectuality in Fe3+ reducing power assay. Flavonoid was found to contain highest within the pet ether fraction of root in terms of quercetin equivalent, equally highest quantity of total phenolic resin compounds (assayed as acid equivalents) were found to contain within the same fraction. The methanol fractions appeared less cytotoxic compared to pet ether extracts. The plant extracts caused a dose dependent decrease in soiled BM in each cathartic and atomic number 12 sulfate induced looseness of the bowels, wherever as leaf extracts in every solvent appeared only. Also, the plant extracts showed anthelmintic activity in oligochaete worm by causing palsy and death in an exceedingly dose dependent manner. At highest doses all fractions were nearly effective because the positive management helminthic citrate.

Conclusion: Thus, besides this cytotoxic effect its traditional claim for therapeutic use can never be overlooked.