First report of collagenase production by Trichosporon sp. strain isolated from pollen of Amazonian bee (Melipona seminigra seminigra)

Trichosporon yeasts are widely employed to produce lipids, lipases, and aspartic peptidases, but there are no previous studies on collagenase production. This work aimed to select the best collagenase producing Amazonian Trichosporon strains. Moreover, a 2³-full factorial design (FFD) and a 2²-central composite design combined with Response Surface Methodology were applied to optimize production and find the best conditions for hydrolysis of type I bovine collagen. Most of the studied strains had some collagenolytic activity, but the selected one achieved the highest value (44.02 U) and a biomass concentration of 2.31 g/L. The best collagenase production conditions were 160 rpm of agitation, pH 5.5 and a substrate concentration of 4.0 g/L. The former experimental design showed that substrate concentration was the only statistically significant factor on both biomass concentration and collagenase activity, while the latter showed simultaneous effects of substrate concentration and pH on collagenolytic activity, which peaked at pH 5.5-6.4 and substrate concentration of 3.0-3.4 g/L. An additional 2³-FFD was finally used to optimize the conditions collagen hydrolysis, and pH 6, 25 °C and a substrate concentration of 7.5 (g/L) ensured the highest hydrolysis degree. This study is the first that describes optimized conditions of collagenase production by Trichosporon strains.

Immobilization of fibrinolytic protease from Mucor subtilissimus UCP 1262 in magnetic nanoparticles

This work reports the immobilization of a fibrinolytic protease (FP) from Mucor subtilissimus UCP 1262 on Fe₃O₄ magnetic nanoparticles (MNPs) produced by precipitation of FeCl₃·6H₂O and FeCl₂·4H₂O, coated with polyaniline and activated with glutaraldehyde. The FP was obtained by solid state fermentation, precipitated with 40-60% ammonium sulfate, and purified by DEAE-Sephadex A50 ion exchange chromatography. The FP immobilization procedure allowed for an enzyme retention of 52.13%. The fibrinolytic protease immobilized on magnetic nanoparticles (MNPs/FP) maintained more than 60% of activity at a temperature of 40 to 60 °C and at pH 7 to 10, when compared to the non-immobilized enzyme. MNPs and MNPs/FP did not show any cytotoxicity against HEK-293 and J774A.1 cells. MNPs/FP was not hemolytic and reduced the hemolysis induced by MNPs from 2.07% to 1.37%. Thrombus degradation by MNPs/FP demonstrated that the immobilization process guaranteed the thrombolytic activity of the enzyme. MNPs/FP showed a total degradation of the γ chain of human fibrinogen within 90 min. These results suggest that MNPs/FP may be used as an alternative strategy to treat cardiovascular diseases with a targeted release through an external magnetic field.

Structural and functional analysis of broad pH and thermal stable protease from Penicillium aurantiogriseum URM 4622

This study aimed to better characterize a recently purified stable extracellular alkaline peptidase produced by Penicillium aurantiogriseum (URM 4622) through fluorescence spectroscopy, far-UV circular dichroism, kinetic and thermodynamic models to understand its' structure-activity and denaturation. Fluorescence data showed that changing pH leads to tryptophan residues exposure to more hydrophilic environments at optimum activity pH 9.0 and 10.0. When thermally treated, it displayed less unfolding at these pH values, along with 4-fold less photoproducts formation than at neutral pH. Different pH CD spectra showed more β-sheet (21.5-43.0%) than α-helix (1-6.2%). At pH9.0, more than 2-fold higher α-helix content than any other pH. The melting temperature (T_m) was observed between 50 and 60 °C at all pH studied, with lower T_m at pH 9.0-11.0 (54.9-50.3 °C). The protease displayed two phase transition, with two energies of denaturation, and a 4-fold higher thermal stability (ΔH°_m) than reports for other microorganism's proteases. An irreversible folding transition occurs between 50 and 60 °C. It displayed energies of denaturation suggesting higher thermal stability than reported for other microorganism's proteases. These results help elucidating the applicability of this new stable protease.

Single step purification via magnetic nanoparticles of new broad pH active protease from Penicillium aurantiogriseum

A new set of applications can be achieved when using high stability proteases. Industrially, high costs can be related to production medium and purification process. Magnetic nanoparticles have been successfully used for rapid and scalable purification. In this work, azocasein were immobilized on magnetite nanoparticles and applied in a single step purification of protease produced by Penicillium aurantiogriseum using soybean flour medium, and the new purified enzyme was characterized. Glutaraldehyde activated nanoparticles were used in azocasein immobilization and then incubated with dialyzed 60-80% saline precipitation fraction of crude extract for purification. Adsorbents were washed 7 times (0.1 M NaCl solution) and eluted 3 times (1 M NaCl solution), these final elutions contained the purified protease. This protease was purified 55.68-fold, retaining 46% of its original activity. Presented approximately 40 kDa on SDS-PAGE and optimum activity at 45 °C and pH 9.0. Maintained over 60% of activity from pH 6.0 to 11.0. Kept more than 50% activity from 15 to 55 °C, did not lose any activity over 48 h at 25 °C. Inhibitors assay suggested a serine protease with aspartic residues on its active site. Results report a successful application of an alternative purification method and novel broad pH tolerant protease.

Optimization of Penicillium aurantiogriseum protease immobilization on magnetic nanoparticles for antioxidant peptides' obtainment

This work reports an optimization of protease from Penicillium aurantiogriseum immobilization on polyaniline-coated magnetic nanoparticles for antioxidant peptides' obtainment derived from bovine casein. Immobilization process was optimized using a full two-level factorial design (2⁴) followed by a response surface methodology. Using the derivative, casein was hydrolyzed uncovering its peptides that were sequenced and had antioxidant properties tested through (2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt) (ABTS) radical scavenging and hydrogen peroxide scavenging assays. Optimal conditions for immobilization were 2 hr of immobilization, offered protein amount of 200 µg/mL, immobilization pH of 6.3 and 7.3 hr of activation. Derivative keeps over 74% of its original activity after reused five times. Free and immobilized enzyme casein hydrolysates presented similar peptide mass fingerprints, and prevalent peptides could be sequenced. Hydrolysates presented more than 2.5× higher ROS scavenging activity than nonhydrolyzed casein, which validates the immobilized protease capacity to develop casein-derived natural ingredients with potential for functional foods.

Collagenolytic enzymes produced by fungi: a systematic review

Specific proteases capable of degrading native triple helical or denatured collagen have been required for many years and have a large spectrum of applications. There are few complete reports that fully uncover production, characterization and purification of fungi collagenases. In this review, authors searched through four scientific on line data bases using the following keywords (collagenolytic OR collagenase) AND (fungi OR fungus OR fungal) AND (production OR synthesis OR synthesize) AND (characterization). Scientific criteria were adopted in this review to classify found articles by score (from 0 to 10). After exclusion criteria, 21 articles were selected. None obtained the maximum of 10 points defined by the methodology, which indicates a deficiency in studies dealing simultaneously with production, characterization and purification of collagenase by fungi. Among microorganisms studied the non-pathogenic fungi Penicillium aurantiogriseum and Rhizoctonia solani stood out in volumetric and specific collagenase activity. The only article found that made sequencing of a true collagenase showed 100% homology with several metalloproteinases fungi. A clear gap in literature about collagenase production by fungi was verified, which prevents further development in the area and increases the need for further studies, particularly full characterization of fungal collagenases with high specificity to collagen.