Development of a continuous-flow tubular reactor for synthesis of 5-hydroxymethylfurfural from fructose using heterogeneous solid acid catalysts in biphasic reaction medium

5-Hydroxymethylfurfural (5-HMF) is an important biomass-derived platform chemical used to produce polymers, biofuels, and other valuable industrial chemicals.

Enzymatic pre-treatment for enhancement of primary sludge fermentation

This research showed the interrelated impact of cellulase enzyme, temperature, and SRT on enhancement of primary and rotating belt filter (PS, RBF) sludges fermentation. SRTs of 1, 2, and 4-days were tested at 25 °C and 35 °C. Enzymatic enhancement was examined using three different doses of enzyme (i.e. 0.5%, 1%, and 1.5% of the total solids in the feed). The results showed a positive impact of enzyme dose as well as temperature and SRT on VFA and soluble COD production. For the RBF sludge, enzyme addition enhanced the VFA yield of fermentation at room temperature (25 °C) from 52-103 mgCOD/g VS to 93-188 mgCOD/g VS, as compared with increase from 78-192 to 87-202 mgCOD/gVS in PS. Intensification of the fermentation process, particularly for the cellulose-rich RBF sludge, by enzyme addition confirms process viability as an alternative to the extraneous carbon sources for biological nutrient removal in wastewater treatment plants.

Seroprevalence and molecular detection of Toxoplasma gondii in healthy blood donors in southwest Iran

BACKGROUND

Toxoplasmosis is a cosmopolitan parasitic disease caused by Toxoplasma gondii (T. gondii). Blood transfusion is a probable route of T. gondii transmission. Due to lack of information about seroprevalence of T. gondii in healthy blood donors, this study was aimed to determine the chronic and acute infection using serological and molecular methods.

MATERIAL AND METHODS

In this cross-sectional investigation, 380 samples were collected from donated bloods. Anti-Toxoplasma IgG and IgM antibodies were examined using enzyme-linked immunosorbent assay (ELISA). Also, all IgG positive samples were tested by IgG avidity test. Eventually, to detection of active infection, DNA was extracted from IgM positive and low IgG avidity samples and then tested using nested-polymerase chain reaction (PCR).

RESULTS

Among 380 blood donors, 131 (34.47%) were positive for only anti-T. gondii IgG, 2 (0.5%) were positive for only anti-T. gondii IgM, and 11 (2.9%) were positive for both IgG and IgM antibodies. Then, 142 samples (131 IgG ⁺ and 11 IgG ⁺IgM ⁺) were evaluated using IgG avidity test. Of these, 115 (81%) had high avidity IgG indicates past infection; 16 (11.26%) had low avidity IgG representing recent infection, and 11 (7.74%) were equivocal. With nested PCR, 20 samples of 50 seropositive samples were diagnosed positive.

CONCLUSION

Detected active infection using nested-PCR draws attention to the possibility of T. gondii infection via blood transfusion which emphasizes the importance of parasite DNA screening before donation of blood in high risk groups such as: multi-transfused persons, immunosuppressed patient, and pregnant women.

Low-temperature thermal pre-treatment of municipal wastewater sludge: Process optimization and effects on solubilization and anaerobic degradation

The present study examines the relationship between the degree of solubilization and biodegradability of wastewater sludge in anaerobic digestion as a result of low-temperature thermal pre-treatment. The main effect of thermal pre-treatment is the disintegration of cell membranes and thus solubilization of organic compounds. There is an established correlation between chemical oxygen demand (COD) solubilization and temperature of thermal pre-treatment, but results of thermal pre-treatment in terms of biodegradability are not well understood. Aiming to determine the impact of low temperature treatments on biogas production, the thermal pre-treatment process was first optimized based on an experimental design study on waste activated sludge in batch mode. The optimum temperature, reaction time and pH of the process were determined to be 80 °C, 5 h and pH 10, respectively. All three factors had a strong individual effect (p < 0.001), with a significant interaction effect for temp. pH² (p = 0.002). Thermal pre-treatments, carried out on seven different municipal wastewater sludges at the above optimum operating conditions, produced increased COD solubilization of 18.3 ± 7.5% and VSS reduction of 27.7 ± 12.3% compared to the untreated sludges. The solubilization of proteins was significantly higher than carbohydrates. Methane produced in biochemical methane potential (BMP) tests, indicated initial higher rates (p = 0.0013) for the thermally treated samples (k_hyd up to 5 times higher), although the ultimate methane yields were not significantly affected by the treatment.