Romero Marcos Pedrosa Brandão-Costa’s research while affiliated with Federal University of Pernambuco and other places

Azo dyes are widely used in the textile industry due to their stability and resistance. These properties also make them recalcitrant xenobiotics, toxic, mutagenic, and carcinogenic, even at low concentrations. Considered emerging pollutants, there is an urgency to address mechanisms capable of remediating these contaminants, with Aspergillus fungi standing out as an effective solution. Fifteen strains of Aspergillus were investigated for the decolorization of the tetra azo dye Direct Black 22. The influence of different culture media was evaluated on fungi biomass production, dye concentrations (50–300 mg/L), biomass concentrations (1–5g), and the reuse of biomass in continuous batches. The strains that stood out the most were Aspergillus japonicus URM 5620, Aspergillus niger URM 5741, and A. niger URM 5838. Obtaining biomass in less nutrient-rich medium favored decolorization by forming more organized pellets. The live biomass of these fungi was 59% more efficient than the dead biomass. The decolorization efficiency was not affected at lower dye concentrations, showing a decrease in decolorization only when the concentration reached 300 mg/L. Increasing the amount of biomass resulted in proportionally greater decolorization. Even with just 1 g of biomass, the three fungi could remove more than 90% of the dye in less than 60 minutes, and with 5 g, the dye was completely removed in 10 minutes. Thebiomass was reused in three consecutive decolorization cycles, and the fungus that best withstood the cycles was A. niger URM 5741. These results demonstrate the potential of the genus Aspergillus fungi tested in this study as sustainable and efficient biosorbents for the remediation of azo dyes such as Direct Black 22, with potential for colored industrial effluent treatment.

(1) Background: Polysaccharide films are promising vehicles for the delivery of bioactive agents such as collagenases, as they provide controlled release at the wound site, facilitating tissue regeneration. This study aimed to investigate the physicochemical properties of Cassia grandis polysaccharide films with immobilized collagenase from Streptomyces parvulus (DPUA/1573). (2) Methods: Galactomannan was extracted from Cassia grandis seeds for film production with 0.8% (w/v) galactomannan and 0.2% (v/v) glycerol with or without collagenases. The films underwent physical-chemical analyses: Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), color and opacity (luminosity-L*, green to red-a*, yellow to blue-b*, opacity-Y%), moisture content, water vapor permeability (WVP), thickness, contact angle, and mechanical properties. (3) Results: The results showed similar FTIR spectra to the literature, indicating carbonyl functional groups. Immobilizing bioactive compounds increased surface roughness observed in SEM. TGA indicated a better viability for films with immobilized S. parvulus enzymes. Both collagenase-containing and control films exhibited a bright-yellowish color with slight opacity (Y%). Mechanical tests revealed decreased rigidity in PCF (−25%) and SCF (−41%) and increased deformability in films with the immobilized bioactive compounds, PCF (234%) and SCF (295%). (4) Conclusions: Polysaccharide-based films are promising biomaterials for controlled composition, biocompatibility, biodegradability, and wound healing, with a potential in pharmacological applications.

Collagenases are proteases able to degrade native and denatured collagen, with broad applications such as leather, food, and pharmaceutical industries. The aim of this research was to purify and characterize a collagenase from Streptomyces antibioticus. In the present work, the coffee ground substrate provided conditions to obtaining high collagenase activity (377.5 U/mL) using anion-exchange DEAE-Sephadex G50 chromatographic protocol. SDS-PAGE revealed the metallo-collagenase with a single band of 41.28 kDa and was able to hydrolyzed type I and type V collagen producing bioactive peptides that delayed the coagulation time. The enzyme activity showed stability across a range of pH (6.0-11) and temperature (30-55 °C) with optima at pH 7.0 and 60 °C, respectively. Activators include Mg+2, Ca+2, Na+, K+, while full inhibition was given by other tested metalloproteinase inhibitors. Kinetic parameters (Km of 27.14 mg/mol, Vmax of 714.29 mg/mol/min, Kcat of 79.9 s-1 and Kcat/Km of 2.95 mL/mg/s) and thermodynamic parameters (Ea of 65.224 kJ/mol, ΔH of 62.75 kJ/mol, ΔS of 1.96 J/mol, ΔG of 62.16 kJ/mol, ΔGE-S of 8.18 kJ/mol and ΔGE-T of -2.64 kJ/mol) were also defined. Coffee grounds showed to be an interesting source to obtaining a collagenase able to produce bioactive peptides with anticoagulant activity.

Solid state fermentation is a promising technology largely used in biotechnology process and is a suitable strategy for producing low-cost enzymatic products. At the present study, a novel enzyme obtained through solid state fermentation using Aspergillus sydowii was herein purified and characterized. The fermentations used coffee ground residue as substrate and the crude enzyme was submitted through further purification steps of: acetonic precipitation, DEAE-Sephadex and Superdex G-75 column. Both crude and purified enzymes were submitted to biochemical characterization of their thermostability, optimal temperature and pH, effects of inhibitors and metal ions. A purified protease was obtained with yield of 5.9-fold and 53% recovery, with maximal proteolytic activity of 352.0 U/mL. SDS-PAGE revealed a band of protein at 47.0 kDa. The enzyme activity was abolished in the presence of phenyl-methyl sulfonyl fluoride and partially inhibited against Triton X-100 (78.0%). The optimal activity was found in pH 8.0 at 45°C of temperature. Besides, the enzyme showed stability between 35°C and 50°C. It was possible to determine appropriate conditions to the obtainment of thermostable proteases with biotechnological interest associated with a method that concomitantly shows excellent production levels and recovery waste raw material in a very profitable process.

Vector-borne diseases are considered public health concerns. As vaccines for some of these diseases are not available or still have serious restrictions, the vector control is an important strategy. Aedes aegypti mosquitoes can transmit dengue, yellow fever, chikungunya and Zika viruses. Chemical compounds are used to control A. aegypti populations which are usually toxic to non-target organisms, and thus the safety of their use is questionable. This work reports the purification and characterization of a lectin from Chlorella vulgaris microalgae (CvL) and its toxicity to the A. aegypti fourth instar larvae (L4). CvL was isolated (purification factor of 8.72; yield of 6.67) from the C. vulgaris aqueous extract (AE) with hemagglutinating activity of 185,130 titre mg⁻¹. The characterization showed that CvL is a 17 kDa protein whose activity was inhibited various carbohydrates, resisted to heating up to 60 °C and was stable over a broad pH range. Additionally, CvL activity was strongly reduced by monovalent and divalent metal ions. AE and CvL were toxic to L4 and the concentrations that killed 50% of larvae after 24 h were 10.62% (v/v) and 164.24 μg mL⁻¹, respectively. CvL inhibited the activity of trypsin-like enzymes from L4 gut and this effect, as well as the larvicidal activity, were abolished when the lectin was denatured by heating or when its carbohydrate-binding site was blocked by fructose or azocasein. These findings points the C. vulgaris biomass as a new source of a biomaterial with potential to control A. aegypti larvae by inhibition of trypsin-like enzymes representing a larvicidal mechanism.

β-fructofuranosidases (EC3.2.1.26) are members of the GH32 family of glycoside hydrolases, which include more than 390 enzymes of vegetable and microbial origins, used in several biotechnological applications. Thus, this research aimed to produce a β-fructofuranosidase obtained by Aspergillus tamarii through solid state fermentation, and to purify by Aqueous Two-Phase System (ATPS). Summary results presented the optimal parameters to produce the β-fructofuranosidase used wheat bran as a substrate at 30 °C for 48 h, and purification process using ATPS with polyethylene glycol and sodium citrate (PEG/sodium citrate), where the β-fructofuranosidase preferably partitioned to the salt-rich phase, the best run (24% of PEG 400, 20% sodium citrate, pH 8) which presented a higher purification factor 6.42 with 12.39 U/mL activity and 352% yield. Optimum parameter was pH 5.15 and temperature of 55 °C, respectively. The purified enzyme showed excellent thermal stability and exhibited a half-life of 60 min at 65 °C. Kinetics results for enzyme showed for Sucrose substrate the enzyme showed Km of 42.9 ± 2.21 mM and Vmax of 180.2 ± 2.8 μM min⁻¹ mg⁻¹ of protein. Although Vmax was the highest for 1-Kestose (219.4 ± 2.7 μM min⁻¹ mg⁻¹ of protein) the preferred substrate of Aspergillus tamarii β-fructofuranosidase (β-FFase) was Nystose (Km of 3.8 ± 0.15 mM). SDS-PAGE revealed a single band of protein at ~66 kDa. Finally, this study demonstrated the potential of ATPS to purify a β-fructofuranosidase with application in biotechnological field aiming to functional foods.