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In this study, cellulose nanocrystals (CNC) were produced from untreated and pretreated sugarcane fibers through enzymatic hydrolysis using a crude cellulolytic extract produced by the fungus Aspergillus fumigatus CCT 7873 using semi-solid fermentation (SSF). The fibers were characterized in terms of cellulose, hemicellulose, and lignin contents and crystallinity index. The CNC generated during the enzymatic hydrolysis using a sugarcane fiber pretreated with 4% NaOH and an enzymatic loading of 7.5 FPU g−1 of bagasse were characterized by atomic force microscopy (AFM). The results showed that after the hydrolysis time of 48 h, spherical-like particles with a good size distribution and a mean diameter of 61 nm were obtained. In this study, we produced cellulose nanocrystals (CNC) from untreated and pretreated sugarcane fibers through enzymatic hydrolysis using a crude cellulolytic extract produced by the fungus Aspergillus fumigatus CCT 7873 using semi-solid fermentation (SSF). In fact, the main novelty of this manuscript is the fact that it accompanies the formation of CNC, by means of atomic force microscopy (AFM). It is noteworthy that there are few manuscripts with this approach in the literature. In addition, this was performed during the cultivation of a fermentation broth containing cellulases produced by an enzymatic extract of the fungus Aspergillus fumigatus CCT 7873 using SSF. Thus, CNC, a highly added value product, can be obtained from lignocellulosic residues, which is a renewable and low-cost source. The results showed that, during the cultivation, there is a variation in the size distribution of the CNC and that, for the hydrolysis time of 48 h, a good size distribution was obtained for the CNC with about 61 nm in diameter, presenting a spherical shape.

The present study aimed to evaluate the influence of induction conditions (IPTG concentration, temperature, and induction time) on the plasmid pQE-30 stability and 503 antigen expression of Leishmania i. chagasi in Escherichia coli M15. Batch cultures were performed at 37 °C and induced by the addition of different IPTG concentrations (0.01 to 1.5 mM). Subsequently, experiments were carried out at different temperatures (27 to 42 °C), evaluating the influence of induction time (0.5 to 6 h after the start of the culture). The results showed that IPTG toxicity caused a metabolic stress in the cells and, consequently, the microorganism growth reduced. The induction with IPTG may also be associated with the plasmid pQE-30 instability, due to metabolic burden imposed by the recombinant protein expression. The optimal conditions for 503 antigen expression of Leishmania i. chagasi in Escherichia coli M15 were an IPTG concentration of 1.0 mM, temperature of 37 °C, and induction time of 2 h. The maximum antigen concentration obtained was 0.119 ± 0.009 g/L, about seven times higher than the lowest concentration. Therefore, the results showed that 503 antigen can be produced in laboratory; however, it requires more studies to minimize the plasmid instability and improve to industrial scale.

2023-03 In this study, the potential of yellow mombin (Spondias mombin L.)–extracted pectin as a film-forming matrix for the elaboration of edible coatings was investigated. The films of chitosan, citric pectin, and carboxymethylcellulose (Sigma/USA) and natural pectin were prepared by casting. The film morphological characterization was performed by scanning electron microscopy (SME), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and atomic force microscopy (AFM). Additionally, total phenolic compounds (TPC), total antioxidant activity (TAC), DPPH scavenging capacity, and antimicrobial activity were assayed for the natural pectin–based films. The results showed that the film based on natural pectin presented a 46% degree of esterification that was higher than commercial (34%), showing its capacity of forming gels. The film formed by chitosan presented a very different behavior for loss of mass during TGA when compared to the other films, occurring a mass loss completely at 647.7 °C in 61 min. The value obtained from the concentration of total phenolics (mg GAE/100 g dried) found in the formulated film based on pectin was 3998.99 ± 42.64 and with solubility in water of almost 100%. Additionally, the scavenging of the DPPH radical with a value of 15.48 ± 1.48 μmol TE/g was found on the film based on natural pectin thus showing antioxidant capacity. Finally, this film showed less significant mechanical properties when compared to other films and a good pronounced antimicrobial effect against the gram-negative bacteria tested. Therefore, it could be potentially used for producing food-active packages

Purpose In this study, an aqueous two-phase micellar system (ATPMS), formed by the non-ionic surfactant Triton X-114, was used to investigate the partitioning of cellulolytic enzymes produced by the filamentous fungus Aspergillus fumigatus CCT 7873. Methods Performance of the ATPMS on the partitioning of CMCase (activity on carboxymethyl cellulose) and FPase (activity on filter paper) was investigated by varying the temperature (35, 40, 45, 50, 55, 60, and 65 °C), enzyme crude extract concentration (20, 40, 60, and 80% w/w), and Triton X-114 concentration (2, 4, 6, and 8% w/w) and by adding different inorganic salts (NaCl, CaCl2, MgSO4, and MnSO4) in the system. Results An ATPMS formed with 8% (w/w) Triton X-114 and 40% (w/w) enzymatic crude extract at a system temperature of 55 °C was most favorable for partitioning the tested enzymes. Under these conditions, a purification factor for CMCase and FPase of 10.89 and 0.65 was reached, respectively. The addition of inorganic salts changed the distribution of enzymes. Of these, CaCl2 contributed to a higher distribution coefficient (50.0), whereas for FPase, the presence of MnSO4 in the system improved the purification factor to 3.94. Conclusion The highest values obtained for the yield and purification factors demonstrate that ATPMS is an interesting option for recovering and purifying cellulolytic enzymes.

A leishmaniose visceral é uma doença parasitária infecciosa causada por protozoários do gênero Leishmania, que pode ser letal quando não é feito um tratamento adequado. O aumento da incidência desta doença torna importante a busca por alternativas de baixo custo para diagnóstico rápido e vacinas. Nesse contexto, o principal objetivo desta pesquisa foi avaliar a influência do IPTG na expressão do antígeno 503 de Leishmania i. Chagasi expresso em Escherichia coli. A bactéria foi cultivada em três ensaios diferentes, chamados Cinética A, B, C, onde a concentração do indutor IPTG foi variada em 10, 100 e 1500 μM, respectivamente. Observou-se que na Cinética C (1500 μM), obteve-se uma maior concentração de proteínas totais e a partir de uma análise qualitativa (eletroforese) observou-se que na cinética A e C obteve-se a melhor expressão do antígeno 503. Para purificação do antígeno,utilizou-se resina de níquel sefarose, operada em leito fixo. Os resultados qualitativos da purificação mostraram que não foi eficiente Visceral leishmaniasis is an infectious-parasitic disease caused by protozoa of the genus Leishmania, which can be lethal when there is no adequate treatment. The increasing incidence of this disease makes important the search for alternatives of low cost for rapid diagnosis and vaccine. In this context, the main objective of this research was to evaluate the influence of IPTG on 503 antigen expression of Leishmania i. chagasi expressed in Escherichia coli. The bacteria was cultured in three different assays, called Kinetics A, B, C where the concentration of the IPTG inducer was varied at 10, 100 and 1500 μM respectively. It was observed that in Kinetics C (1500μM), it was obtained a higher concentration of native proteins and from a qualitative analysis (electrophoresis) it was observed that in Kinetics A and C obtained the best expression of 503 antigen. For purification of the antigen, the Nickel Sepharose Resin, operated in fixed bed was used. The qualitative results of the purification showed that it was not efficient

Agroindustrial biomasses (sugarcane bagasse, green coconut husk and cashew apple bagasse) are used as substrate for producing cellulases by Aspergillus fumigatus on Semi-Solid Fermentation (SSF). The untreated lignocellulosics and fermented sugarcane bagasse are characterized using the National Renewable Energy Laboratory (NREL) protocols analysis as well as through Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) assays. A two-variable central composite rotatable design (CCRD) coupled to response surface methodology (RSM) with three experiments at center point are used to investigate the influence of initial moisture and pH on carboxymethycellulose and filter paper, i.e., CMCase and FPase activities produced by the Aspergillus fumigatus using all of the three lignocellulosic biomasses. Results show that sugarcane bagasse has the highest cellulose content and the cashew apple bagasse the highest lignin content, approximately 46.0%. Additionally, pH and moisture (linear and quadratic parameters), as well as their combination, play a key role on both CMCase and FPase activities. The highest values for CMCase and FPase are 4.20 U/g and 0.64 U/g for sugarcane bagasse; 4.07 U/g and 0.28 U/g for coconut husk and 0.64 U/g and 0.32 U/g for cashew apple bagasse. The use of SSF for producing cellulases can be an option for reducing energy consumption due to reduction on the steps during biomass pretreatment.