Cloned Bacillus subtilis Alkaline Protease (aprA) Gene Showing High Level of Keratinolytic Activity

Zaghloul, Taha I.

doi:10.1007/978-1-4612-1814-2_19

Cited by 11 publications

(14 citation statements)

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“…This alkaline protease enzyme (aprE), a key enzyme in the keratin degradation process, is a dual enzyme. It is working as a protease and as a keratinase at the same time as reported earlier by Zaghloul 1998. Since 1990, researchers have given a great attention to the valorization of chicken feather waste through biotechnological methods. On the other hand, a very little attention has been paid to another protein rich unutilized keratinous waste; sheep wool waste.…”

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confidence: 70%

“…Low expression as well as low stability of the recombinant plasmids carrying keratinase genes are both considered obstacles to maximizing the amount of keratinase produced by genetically modified cells (Ramnani et al 2005). High expression level of a keratinolytic serine alkaline protease (apr E gene) from the B. subtilis DB 100 (pS1) and B. subtilis DB 100 (p5.2) recombinant strains (Zaghloul et al 1994;Zaghloul 1998;Zaghloul et al 2004;Oulad Haddar et al 2009) was reported. Biodegradation of keratin in the form of chicken feathers by the B. subtilis DB 100 (p5.2) recombinant cells was accompanied with the production of considerable levels of keratinolytic alkaline protease, soluble proteins and NH 2 -free amino groups (Oulad Haddar et al 2009).…”

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confidence: 99%

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Key determinants affecting sheep wool biodegradation directed by a keratinase-producing Bacillus subtilis recombinant strain

2010

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OVAT (one variable at a time) approach was applied in this study to screen the most important physicochemical key determinants involved in the process of sheep wool biodegradation. The process was directed by a keratinase-producing Bacillus subtilis DB 100 (p5.2) recombinant strain. Data indicate that, sheep wool could be degraded efficiently in cultures incubated at 30°C, with initial pH of 7 with agitation at 150 rpm. Two times autoclaved alkali treated and undefatted chopped sheep wool is more accessible to biodegradation. B. subtilis recombinant cells could utilize sheep wool as a sole source of carbon and nitrogen. Sheep wool-based modified basal medium II, lacking NH₄Cl and yeast extract, could greatly support the growth of these bacterial cells. Sheep wool biodegradation was conducted efficiently in the absence of kanamycin consequently; high stability of the recombinant plasmid (p5.2) represents a great challenge upon scaling up this process. Three key determinants (sheep wool concentration, incubation time and inoculum size) imposing considerable constraints on the process are highlighted. Sheep wool-based tap water medium and sheep wool-based distilled water medium were formulated in this study. High levels of released end products, produced from sheep wool biodegradation are achieved upon using these two sheep wool-based water media. Data indicate that, sheep wool hydrolysate is rich in some amino acids, such as tyrosine, phenylalanine, lysine, proline, isoleucine, leucine, valine, aspartic acid and glutamic acid. Moreover, the resulting sheep wool hydrolysate contains soluble proteins of high and intermediate molecular weights. The present study demonstrates a feasible, cheap, reproducible, efficient and rapid biotechnological approach towards utilization of raw sheep wool waste through a recombinant bacterium.

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Key determinants affecting sheep wool biodegradation directed by a keratinase-producing Bacillus subtilis recombinant strain

2010

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“…Among the members of the genus Bacillus, a number of B. licheniformis isolates have been reported to possess feather-degrading activity (Williams et al 1990;Kim et al 2001;Rozs et al 2001). Keratinases from Bacillus are often serine-type proteases of the subtilisin family (Lin et al 1995;Zaghloul 1998), but recently a metalloprotease from a keratinolytic strain of Bacillus sp. (Werlang and Brandelli 2005) was described.…”

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confidence: 99%

Keratinolytic proteases of Bacillus species isolated from the Amazon basin showing remarkable de-hairing activity

Giongo

Lucas

Casarin

et al. 2006

World J Microbiol Biotechnol

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Three keratinolytic Bacillus spp. isolated from the Brazilian Amazon basin were characterized. The strains P6, P7 and P11 were identified based on morphological and biochemical characteristics and 16S rDNA sequences. P6, P7 and P11 sequences shared more than 99% similarity with B. subtilis, B. amyloliquefaciens and B. velesensis. The keratinases produced by these bacteria were active on azokeratin and degradation of feather barbules was observed. The enzymes were inhibited by the serine protease inhibitor PMSF, and showed maximum activity at pH 9.0. Proteins like albumin, casein and gelatin were hydrolysed by these keratinases. Depilatory studies on bovine pelts revealed that all three strains were efficient in promoting de-hairing. Microscopic analysis showed that the epidermis was completely removed and the absence of hair in follicles was observed.

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“…The keratinases produced by Bacillus are often serine proteases, such as the enzymes produced by B. licheniformis (Lin et al 1999), B. pseudofirmus (Kojima et al 2006), and B. subtilis (Zaghloul 1998;Suh and Lee 2001). However, the enzyme produced by the Bacillus sp.…”

Section: Discussionmentioning

confidence: 99%

“…Feather degradation and keratinase production by Bacillus spp. have been extensively studied in B. licheniformis and B. subtilis, and the keratinases belonging to the subtilisin family of serine proteases (Zaghloul 1998;Thys et al 2004).…”

Section: Introductionmentioning

confidence: 99%

Isolation and characterization of a new Bacillus sp. 50-3 with highly alkaline keratinase activity from Calotes versicolor faeces

Zhang

Jiang

Zhou

et al. 2008

World J Microbiol Biotechnol

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A new native feather-degrading bacterium has been isolated from the faeces of the agamid lizard Calotes versicolor, collected from the Beijing Zoo in China. The isolate, which has been identified as Bacillus sp. 50-3 based on morphological and biochemical and 16S rDNA tests, was shown to degrade native feather completely at 37°C and pH 7.0 within 36 h when using chicken feathers as the sole carbon and nitrogen source. Bacillus sp. 50-3 presented optimum growth at 37°C and pH 7.0 in feather meal medium. Under these conditions, the maximum keratinase activity (680 ± 25 U/ml) was also achieved. The keratinase of Bacillus sp. 50-3 was active over a broad range of pH values and temperatures toward azokeratin, and presented an optimum pH and temperature of 10.0 and 60°C, respectively. Furthermore, it was relatively heat-and alkalistable. Inhibitor studies showed that it seemed to belong to the serine-metalloprotease type. Therefore, the enzyme from Bacillus sp. 50-3 is a novel, high alkaline keratinase, suggesting its potential use in biotechnological processes.

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Cloned Bacillus subtilis Alkaline Protease (aprA) Gene Showing High Level of Keratinolytic Activity

Cited by 11 publications

References 11 publications

Key determinants affecting sheep wool biodegradation directed by a keratinase-producing Bacillus subtilis recombinant strain

Key determinants affecting sheep wool biodegradation directed by a keratinase-producing Bacillus subtilis recombinant strain

Keratinolytic proteases of Bacillus species isolated from the Amazon basin showing remarkable de-hairing activity

Isolation and characterization of a new Bacillus sp. 50-3 with highly alkaline keratinase activity from Calotes versicolor faeces

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