Identification of two new keratinolytic proteases from a Bacillus pumilus strain using protein analysis and gene sequencing

Fellahi, Soltana; Chatti, Abdelwaheb; Feuk-Lagerstedt, Elisabeth; Taherzadeh, Mohammad J.

doi:10.1186/s13568-016-0213-0

Cited by 30 publications

(20 citation statements)

References 24 publications

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“…To date, by using different assays (see Section 3.2 ), keratinolytic enzymes have been shown to be produced by both bacteria and fungi. Some of the prominent producers are bacterial species, such as B. licheniformis , B. subtilis, and B. pumilus ( Fellahi et al, 2016 ; Gupta and Singh, 2013 ; Ramnani and Gupta, 2004 ), as well as actinobacteria, such as Streptomyces fradiae , Nocardiopsis sp. ( Li et al, 2007 ; Mitsuiki et al, 2004 ).…”

Section: Keratinolytic Enzymes and Keratinase Assaysmentioning

confidence: 99%

Microbial enzymes catalyzing keratin degradation: Classification, structure, function

Qiu

Wilkens

Barrett

et al. 2020

Biotechnology Advances

157

103

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Keratin is an insoluble and protein-rich epidermal material found in e.g. feather, wool, hair. It is produced in substantial amounts as co-product from poultry processing plants and pig slaughterhouses. Keratin is packed by disulfide bonds and hydrogen bonds. Based on the secondary structure, keratin can be classified into α-keratin and β-keratin. Keratinases (EC 3.4.-.- peptide hydrolases) have major potential to degrade keratin for sustainable recycling of the protein and amino acids. Currently, the known keratinolytic enzymes belong to at least 14 different protease families: S1, S8, S9, S10, S16, M3, M4, M14, M16, M28, M32, M36, M38, M55 (MEROPS database). The various keratinolytic enzymes act via endo -attack (proteases in families S1, S8, S16, M4, M16, M36), exo -attack (proteases in families S9, S10, M14, M28, M38, M55) or by action only on oligopeptides (proteases in families M3, M32), respectively. Other enzymes, particularly disulfide reductases, also play a key role in keratin degradation as they catalyze the breakage of disulfide bonds for better keratinase catalysis. This review aims to contribute an overview of keratin biomass as an enzyme substrate and a systematic analysis of currently sequenced keratinolytic enzymes and their classification and reaction mechanisms. We also summarize and discuss keratinase assays, available keratinase structures and finally examine the available data on uses of keratinases in practical biorefinery protein upcycling applications.

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Section: Keratinolytic Enzymes and Keratinase Assaysmentioning

confidence: 99%

Microbial enzymes catalyzing keratin degradation: Classification, structure, function

Qiu

Wilkens

Barrett

et al. 2020

Biotechnology Advances

157

103

View full text Add to dashboard Cite

show abstract

“…Thus, keratinous materials can remain inert in the environment for a long time, as keratinase producing microorganisms are not widespread (Lange et al 2016). However, despite their rigid structure, keratins are recycled in nature and can be efficiently degraded by a few microorganisms such as bacteria from the genus Bacillus (Fellahi et al 2016), Streptomyces (Ramakrishnan et al 2011) from several species of fungi (El-Gendy 2010; Duarte et al 2011;Bohacz 2017) and from Archaea (Kublanov et al 2009;Brandelli et al 2010) that are capable of producing keratinolytic peptidases known as keratinases.…”

Section: Introductionmentioning

confidence: 99%

Keratinolytic activity of Bacillus subtilis LFB-FIOCRUZ 1266 enhanced by whole-cell mutagenesis

et al. 2018

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Discarded feathers represent an important residue from the poultry industry and are a rich source of keratin. Bacillus subtilis LFB-FIOCRUZ 1266, previously isolated from industrial poultry wastes, was used in this work and, through random mutation using ethyl methanesulfonate, ten strains were selected based on the size of their degradation halos. The feather degradation was increased to 115% and all selected mutants showed 1.4-to 2.4-fold increase in keratinolytic activity compared to their wild-type counterparts. The protein concentrations in the culture supernatants increased approximately 2.5 times, as a result of feather degradation. The mutants produced more sulfide than the wild-type bacteria that produced 0.45 µg/ml, while mutant D8 produced 1.45 µg/ml. The best pH for enzyme production and feather degradation was pH 8. Zymography showed differences in the intensity and molecular mass of some bands. The peptidase activity of the enzyme blend was predominantly inhibited by PMSF and EDTA, suggesting the presence of serine peptidases. HPTLC analysis evidenced few differences in band intensities of the amino acid profiles produced by the mutant peptidase activities. The mutants showed an increase in keratinolytic and peptidase activities, demonstrating their biotechnological potential to recycle feather and help to reduce the environmental impact.

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“…By definition, keratinases are proteolytic enzymes (peptidases or proteases) that are capable of cleaving peptide bonds Responsible Editor: Inês Conceição Roberto in keratin [8]. Most studies on keratinases have mainly identified and characterized the alkaline monomeric serine peptidases [9][10][11][12][13][14][15][16][17][18] and less frequently, the alkaline monomeric metallopeptidases [19][20][21][22][23]. Some studies have also described aspartic keratinases isolated from yeasts [24,25] and dimeric keratinases [13].…”

Section: Introductionmentioning

confidence: 99%

Citrobacter diversus-derived keratinases and their potential application as detergent-compatible cloth-cleaning agents

et al. 2020

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Currently, poultry farming is one of the sectors that have a significant impact on the global economy. In recent years, there has been an increase in the production of broilers, inflicting this segment of the industry to generate tons of keratin due to huge disposal of chicken feathers. This points to the need to degrade these chicken feathers, as they have emerged as a major threat to the environment. Thus, in this study we aimed to identify keratinases that are produced by the bacterium Citrobacter diversus and further investigate the biochemical characteristics of these keratin-degrading enzymes. In a submerged medium, the bacterium was capable of degrading chicken feathers almost completely after 36 h of fermentation. We found a maximum caseinolytic activity at pH 9-10.5 and 50-55°C, and keratinolytic activity at pH 8.5-9.5 and 50°C. Thus, given its stability at higher temperatures, upon incubation of this enzyme extract for 1 h at 50°C, it showed approximately 50% of the keratinolytic and 100% of the caseinolytic activity. Further, under pH stability for 48 h at 4°C, the enzyme extract maintained greater residual activity in the pH range 6-8. Caseinolytic activity was inhibited by EDTA and PMSF, whereas the keratinolytic activity was inhibited only by EDTA. Additionally, due to its alkaline activity and detergent compatibility, this enzyme extract could improve washing performance when added to a commercial detergent formulation. Using application tests, we could demonstrate a potential use of this bacterial enzyme extract as an additive in detergents to remove egg stains from cloth.

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Identification of two new keratinolytic proteases from a Bacillus pumilus strain using protein analysis and gene sequencing

Cited by 30 publications

References 24 publications

Microbial enzymes catalyzing keratin degradation: Classification, structure, function

Microbial enzymes catalyzing keratin degradation: Classification, structure, function

Keratinolytic activity of Bacillus subtilis LFB-FIOCRUZ 1266 enhanced by whole-cell mutagenesis

Citrobacter diversus-derived keratinases and their potential application as detergent-compatible cloth-cleaning agents

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