Leptospirosis is a zoonose that is increasingly endemic in built-up areas, especially where there are communities living in precarious housing with poor or non-existent sanitation infrastructure. Leptospirosis can kill, for its symptoms are easily confused with those of other diseases. As such, a rapid diagnosis is required so it can be treated effectively. A test for leptospirosis diagnosis using Leptospira Immunoglobulin-like (Lig) proteins is currently at final validation at Fiocruz. In this work, the process for expression of LigB (131-645aa) in E. coli BL21 (DE3)Star™/pAE was evaluated. No significant difference was found for the experiments at two different pre-induction temperatures (28°C and 37°C). Then, the strain was cultivated at 37°C until IPTG addition, followed by induction at 28°C, thereby reducing the overall process time. Under this condition, expression was assessed using central composite design for two variables: cell growth at which LigB (131-645aa) was induced (absorbance at 600 nm between 0.75 and 2.0) and inducer concentration (0.1 mM to 1 mM IPTG). Both variables influenced cell growth and protein expression. Induction at the final exponential growth phase in shaking flasks with Absind = 2.0 yielded higher cell concentrations and LigB (131-645aa) productivities. IPTG concentration had a negative effect and could be ten-fold lower than the concentration commonly used in molecular biology (1 mM), while keeping expression at similar levels and inducing less damage to cell growth. The expression of LigB (131-645aa) was associated with cell growth. The induction at the end of the exponential phase using 0.1 mM IPTG at 28°C for 4 h was also performed in microbioreactors, reaching higher cell densities and 970 mg/L protein. LigB (131-645aa) was purified by nickel affinity chromatography with 91% homogeneity. It was possible to assess the effects and interactions of the induction variables on the expression of soluble LigB (131-645aa) using experimental design, with a view to improving process productivity and reducing the production costs of a rapid test for leptospirosis diagnosis.

Currently, stem cell research faces a major bottleneck related to the low efficiency of methods to produce large quantities of human embryonic stem cells (ESC) for use in clinical trials. Most culture media currently employed for human ESC cultivation contain animal compounds, and cells are grown in static flasks. Besides the immediate contamination with nonhuman compounds, cell expansion in flasks tends to be laborious and nonefficient. Here we cultured human ESC in stirred microcarrier (MC) systems using an animal/human-component-free medium, to overcome both issues. The method developed to culture cells on suspended beads combined the use of polymeric MCs in stirred vessels with an optimized culture medium free of supplements of animal and human origin. This approach generated approximately 160 million cells within 6 days, which were shown to remain pluripotent. The process developed herein provides a step forward toward therapy due to the economic advantages in the production of human ESC and to their consequent low immunogenic potential.

The brewer's spent grain (BSG) is a byproduct of the brewing industry produced in large quantities and with few ecological disposal options. The use of this low-cost residue was investigated for the removal of methylene blue (MB) and tartrazine yellow (TY) dyes. The BSG has been extensively characterized to obtain its physicochemical characteristics. Batch experiments were conducted to investigate the effects of biosorption parameters: initial pH, kinetics, equilibrium isotherms and adsorption thermodynamics. The characterization showed high carbon content and heterogeneous morphology with presence of meso and macropores. The best experimental conditions were obtained as pH 11 for MB and pH 2 for TY. Kinetics resulted in an equilibrium time of 240 min for MB and 300 min for TY and was best represented by the pseudo-second order model. Different interactions mechanisms were suggested, such as electrostatic interactions, electron donors and electron acceptors, hydrogen bonds, π-π dispersion interactions and the dye molecules aggregation. Equilibrium data were better represented by Langmuir isotherm. The maximum adsorbed amount of MB and TY was 284.75 and 26.18 mg/g, respectively, in each better experimental condition. Through the thermodynamic analysis, it was observed that the adsorption of the dyes was spontaneous and favorable. MB is preferentially retained through chemisorption, whereas TY followed a physical process. Considering the characteristics and results found compared to the recent literature, it was verified that BSG can be used as an effective and innovative biosorbent for removal purposes of dyeing effluent.

Contamination of water resources by pathogenic microorganisms is a major concern worldwide. As an example, hospitals generate effluents with a wide range of chemical and microbiological contaminants. These effluents are generally not treated beforehand due to the high costs and are, therefore, mixed with domestic effluents in regional treatment systems. Thus, actions to maintain water quality include the development of appropriate materials for its sustainable treatment. In this context, this study aims to develop natural antibacterial materials by impregnating aqueous and alcoholic extracts of garlic in activated babassu charcoal to reduce the microbial load of effluents. This material has been tested in a standard saline solution, which simulates the composition of hospital wastewater and allows bacteria to develop. The biomaterials were characterized by Scanning Electron Microscopy, pH_PZC assays, Boehm’s method, and microbiological assays. Significant antibacterial activities were verified for the garlic extract-impregnated biomaterials; the activated carbon functionalized with HNO₃ and impregnated with aqueous garlic extract inhibited 100% of E. coli growth. This result pointed to garlic extract associated with babassu activated carbon as a green alternative for the pre-treatment of complex effluents, such as hospital effluents.