Peptidase from Aspergillus niger NRRL 3: Optimization of its production by solid-state fermentation, purification and characterization
Open accessAbstract
Orange peels, soybean hulls, Ilex paraguariensis and Platanus x hispanica were evaluated as solid substrates in order to produce peptidases from Aspergillus niger NRRL3 (PAN) under solid-state fermentation. The mixture of soybean hulls and orange peels enabled fungal development and showed the highest peptidase production. The optimal conditions for PAN production were found to be as follows: soybean hulls/orange peels mass ratio, 0.25; initial pH, 7.05; K₂HPO₄ 43.5 g/L and 4.03 g/L NaNO₃; inoculation with 5000 conidia per 3 g of solid substrate; incubation conditions, 30 °C for 5 days. Under these conditions, the peptidase activity was 1000 ± 100 AU/mL. PAN concentration was performed by adsorption on a DEAE-cellulose matrix. The subsequent purification was carried out by gel filtration on Sephadex G-100, with a global purification factor of about 9. PAN proved to belong to the serine-type of peptidases, its highest peptidase activity being at 65 °C. However, proteolysis at 60 °C proved more suitable due to the differences in the inactivation rate. Besides, PAN showed high stability over a pH range of 4–11. Taking all this into account, we herein describe the production and purification of a serine peptidase from Aspergillus niger NRRL3 for the first time.
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The milk-clotting activity of the Aspergillus niger enzyme was retained in the temperature range of 30°C to 75°C at a level of at least 40%.
“The MCA of this enzyme was retained in the temperature range of 30°C to 75°C at a level of at least 40%.”
From Invited review: Milk-clotting enzymes of microbial origin and their role in cheesemaking-A review. (2025) · cites this paper as López et al., 2018
Section 3.5 reports that the Aspergillus niger peptidase retained at least 40% activity from 30°C to 75°C. But Section 2.8 says temperature-dependent activity was measured by casein hydrolysis; the paper does not establish that milk-clotting activity (MCA) was retained at that level. (LLM, conf=0.91)
Experimental — accuracy not yet measuredThe optimum temperature of the enzyme produced by Aspergillus niger assessed by López et al. (2018) was 65°C.
“The optimum temperature of the enzyme produced by A. niger assessed in the study by López et al. (2018), was 65°C.”
From Invited review: Milk-clotting enzymes of microbial origin and their role in cheesemaking-A review. (2025) · cites this paper as López et al., 2018
The high temperature required for milk coagulation by Bacillus spp. P7 MCE may have contributed to the reduced firmness and fracture force of the resulting gels compared with the rennet gels obtained at 35°C.
“The high temperature required for milk coagulation by Bacillus spp.P7 MCE may have contributed to the reduced firmness and fracture force of the resulting gels compared with the rennet gels obtained at 35°C.”
From Invited review: Milk-clotting enzymes of microbial origin and their role in cheesemaking-A review. (2025) · cites this paper as López et al., 2018
Section 3.5 characterizes the temperature-dependent activity of a peptidase from Aspergillus niger, not milk coagulation by Bacillus P7. Searches for Bacillus P7, milk coagulation, gel firmness, fracture force, and rennet found no passage addressing the claimed comparison. (LLM, conf=0.76)
Experimental — accuracy not yet measuredAmazonian Bacillus spp. P7 can be used as a milk coagulant.
“López et al. (2018) showed that Amazonian Bacillus spp.P7 can be used as a milk coagulant, although the resulting milk gels exhibited slightly lower firmness and fracture force than those induced by rennet.”
From Invited review: Milk-clotting enzymes of microbial origin and their role in cheesemaking-A review. (2025) · cites this paper as López et al., 2018
The Materials section (page unavailable) identifies the study organism as Aspergillus niger NRRL3, not Amazonian Bacillus spp. P7. Searches for Bacillus P7, milk coagulation, and rennet found no passage in our copy addressing P7’s use as a milk coagulant; a reference to a milk-clotting enzyme concerns Aspergillus niger. (LLM, conf=0.76)
Experimental — accuracy not yet measuredMilk gels produced with Amazonian Bacillus spp. P7 MCE exhibited slightly lower firmness and fracture force than those induced by rennet.
“López et al. (2018) showed that Amazonian Bacillus spp.P7 can be used as a milk coagulant, although the resulting milk gels exhibited slightly lower firmness and fracture force than those induced by rennet.”
From Invited review: Milk-clotting enzymes of microbial origin and their role in cheesemaking-A review. (2025) · cites this paper as López et al., 2018
The Materials section identifies the organism studied as Aspergillus niger NRRL 3, not Amazonian Bacillus spp. P7. Searches for Bacillus P7, milk gels, firmness, fracture force, and rennet found no passage reporting the claimed comparison; the copy is not marked as truncated. (LLM, conf=0.78)
Experimental — accuracy not yet measured
Reduced-strength milk gels prepared using Bacillus spp. P7 MCE may be attributed to the low MCA/PA ratio exhibited by this microbial coagulant.
“Reduced-strength milk gels prepared using Bacillus spp.P7 MCE may be attributed to the low MCA/PA ratio exhibited by this microbial coagulant.”
From Invited review: Milk-clotting enzymes of microbial origin and their role in cheesemaking-A review. (2025) · cites this paper as López et al., 2018
The Materials section (2.1; page unavailable) identifies Aspergillus niger NRRL 3 as the strain studied, and Analytical methods (2.9; page unavailable) describes a casein-based peptidase assay. Searches for Bacillus spp. P7, milk-gel strength, and the MCA/PA ratio found no passage addressing the proposed explanation. (LLM, conf=0.76)
Experimental — accuracy not yet measured
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References 53 · Cited by 18
- Authors
- López, D. N., Galante, M., Ruggieri, G., Piaruchi, J., Dib, M. E., Duran, N. M., Lombardi, J., de Sanctis, M., Boeris, V., Risso, P. H., & Spelzini, D.
- Affiliations
- Consejo Nacional de Investigaciones Científicas y Técnicas (AR)
- National University of Rosario (AR)
- Corresponding author
- Spelzini, Darío
- ORCID
- Venue
- LWT
- Publisher
- Elsevier BV
- Published
- 2018-12
- Volume
- 98
- Pages
- 485-491
- ISSN
- 0023-6438 (ISSN-L)
- OpenAlex
- W2891547563
- Cited by
- 18
- References
- 53
- Citations by year
- 2025: 3 · 2024: 1 · 2023: 2 · 2022: 3 · 2021: 3 · 2020: 3 · 2019: 3
- FWCI
- 1.42
- Type
- journal article
- Language
- en
- Open access
- bronze
- doi.org
- Locations
- LWT (publishedVersion)
- LA Referencia (Red Federada de Repositorios Institucionales de Publicaciones Científicas) (submittedVersion, cc-by-nc-sa)
- Americanae (AECID Library) (submittedVersion, cc-by-nc-sa)
- Conicet (submittedVersion, cc-by-nc-sa)
- Funders
- Universidad Nacional de Rosario (1BIO585)
- Agencia Nacional de Promoción Científica y Tecnológica (PICT 2017-0937)
- Secretaría de Políticas Universitarias (VT12-UNR4183)
- Universidad Católica Argentina and Fundación Nuevo Banco de Santa Fe
- Topics
- Life Sciences › Biochemistry, Genetics and Molecular Biology › Biotechnology › Enzyme Production and Characterization
- Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Enzyme Catalysis and Immobilization
- Health Sciences › Medicine › Oncology › Peptidase Inhibition and Analysis
- Keywords
- Aspergillus niger, serine protease, solid-state fermentation, enzyme production optimization, orange peel, soybean hulls, agro-industrial substrates, enzyme purification, DEAE-cellulose adsorption, size exclusion chromatography, thermal stability, pH stability, proteolysis
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