Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2011:2011:487093.
doi: 10.4061/2011/487093. Epub 2011 Oct 10.

Production of Proteolytic Enzymes by a Keratin-Degrading Aspergillus niger

Fernanda Cortez Lopes  1 , Lucas André Dedavid E Silva, Deise Michele Tichota, Daniel Joner Daroit, Renata Voltolini Velho, Jamile Queiroz Pereira, Ana Paula Folmer Corrêa, Adriano Brandelli
Affiliations

Production of Proteolytic Enzymes by a Keratin-Degrading Aspergillus niger

Fernanda Cortez Lopes et al. Enzyme Res. 2011.

Abstract

A fungal isolate with capability to grow in keratinous substrate as only source of carbon and nitrogen was identified as Aspergillus niger using the sequencing of the ITS region of the rDNA. This strain produced a slightly acid keratinase and an acid protease during cultivation in feather meal. The peak of keratinolytic activity occurred in 48 h and the maximum proteolytic activity in 96 h. These enzymes were partly characterized as serine protease and aspartic protease, respectively. The effects of feather meal concentration and initial pH on enzyme production were evaluated using a central composite design combined with response surface methodology. The optimal conditions were determined as pH 5.0 for protease and 7.8 for keratinase and 20 g/L of feather meal, showing that both models were predictive. Production of keratinases by A. niger is a less-exploited field that might represent a novel and promising biotechnological application for this microorganism.

PubMed Disclaimer

Figures

Figure 1
Figure 1
(a) Macromorphology of A. niger on PDA. (b) Micromorphology of A. niger using optic microscope (1000x). (c) The neighbor-joining tree inferred from the partial sequence of the ITS region data set using Mega 4.0 according to Jukes-Cantor Modell. Bootstrap values from 1000 replications are indicated by the nodes.
Figure 2
Figure 2
(a) Production of proteolytic activity and (b) production of keratinolytic activity by A. niger growing on different keratinous substrates (10 g/L). (■) Bovine horn, (∆) chicken feathers, (▲) feather meal, (◆) human hair, and (●) pig hair.
Figure 3
Figure 3
(a) Proteolytic activity of a 96-hour culture and (b) keratinolytic activity of a 48-hour culture of A. niger growing on 10 g/L feather meal at different pH (2.5–8.5).
Figure 4
Figure 4
Enzymatic activity of protease (◆) and keratinase (●) during the 120-hour culture. The assay was performed in the optimum pH of each enzyme.
Figure 5
Figure 5
Zymogram analysis of (1) 24, (2) 48, (3) 72, (4) 96, and (5) 120-hour cultures supernatants of A. niger using citrate buffer pH 4.5.
Figure 6
Figure 6
Response surface plots of protease (a) and keratinase (b) production by A. niger as a function of pH and feather meal concentration.
See this image and copyright information in PMC

References

    1. Roth AHFJ, Dersch P. A novel expression system for intracellular production and purification of recombinant affinity-tagged proteins in Aspergillus niger . Applied Microbiology and Biotechnology. 2010;86(2):659–670. - PubMed
    1. Schuster E, Dunn-Coleman N, Frisvad J, van Dijck P. On the safety of Aspergillus niger—a review. Applied Microbiology and Biotechnology. 2002;59(4-5):426–435. - PubMed
    1. van Dijck PWM, Selten GCM, Hempenius RA. On the safety of a new generation of DSM Aspergillus niger enzyme production strains. Regulatory Toxicology and Pharmacology. 2003;38(1):27–35. - PubMed
    1. Jarai G, Buxton F. Nitrogen, carbon, and pH regulation of extracellular acidic proteases of Aspergillus niger . Current Genetics. 1994;26(3):238–244. - PubMed
    1. Vishwanatha KS, Appu Rao AG, Singh SA. Characterisation of acid protease expressed from Aspergillus oryzae MTCC 5341. Food Chemistry. 2009;114(2):402–407.

LinkOut - more resources