A current assessment on the production of bacterial keratinases

References

• Adigüzel AC, Bitlisli BO, Yaşa I, Eriksen NT. (2009). Sequential secretion of collagenolytic, elastolytic, and keratinolytic proteases in peptide-limited cultures of two Bacillus cereus strains isolated from wool. J Appl Microbiol, 107, 226–34
   PubMed Web of Science ®Google Scholar
• Ahuja SK, Ferreira GM, Moreira AR. (2004). Utilization of enzymes for environmental applications. Crit Rev Biotechnol, 24, 125–54
   PubMed Web of Science ®Google Scholar
• Anbu P, Gopinath SCB, Hilda A, et al. (2006). Secretion of keratinolytic enzymes by Scopulariopsis brevicaulis and Trichophyton mentagrophytes: regression analysis. Can J Microbiol, 52, 1060–9
   PubMed Web of Science ®Google Scholar
• Anbu P, Gopinath SCB, Hilda A, et al. (2007). Optimization of extracellular keratinase production by poultry farm isolate Scopulariopsis brevicaulis. Bioresour Technol, 98, 1298–303
   PubMed Web of Science ®Google Scholar
• Anbu P, Hilda A, Sur HW, et al. (2008). Extracellular keratinase from Trichophyton sp. HA-2 isolated from feather dumping soil. Int Biodeterior Biodegrad, 62, 287–92
   Web of Science ®Google Scholar
• Arai KM, Takahashi R, Yokote Y, Akahane K. (1983). Amino-acid sequence of feather keratin from fowl. Eur J Biochem, 132, 501–7
   PubMedGoogle Scholar
• Awad GEA, Esawy MA, Salam WA, et al. (2011). Keratinase production by Bacillus pumilus GHD in solid-state fermentation using sugar cane bagasse: optimization of culture conditions using a Box-Behnken experimental design. Ann Microbiol, 61, 663–72
   Web of Science ®Google Scholar
• Barone JR, Schmidt WF, Liebner CFE. (2005). Thermally processed keratin films. J Appl Polym Sci, 97, 1644–51
   Web of Science ®Google Scholar
• Bernal C, Diaz I, Coello N. (2006). Response surface methodology for the optimization of keratinase production in culture medium containing feathers produced by Kocuria rosea. Can J Microbiol, 52, 445–50
   PubMed Web of Science ®Google Scholar
• Bertsch A, Coello N. (2005). A biotechnological process for treatment and recycling poultry feathers as a feed ingredient. Bioresour Technol, 96, 1703–8
   PubMed Web of Science ®Google Scholar
• Bierbaum G, Giesecke UE, Wandrey C. (1991). Analysis of nucleotide pools during protease production with Bacillus licheniformis. Appl Microbiol Biotechnol, 35, 725–30
   Web of Science ®Google Scholar
• Blyskal B. (2009). Fungi utilizing keratinous substrates. Int Biodeterior Biodegrad, 63, 631–53
   Web of Science ®Google Scholar
• Brandelli A. (2008). Bacterial keratinases: useful enzymes for bioprocessing agroindustrial wastes and beyond. Food Bioprocess Technol, 1, 105–16
   Web of Science ®Google Scholar
• Brandelli A, Daroit DJ, Riffel A. (2010). Biochemical features of microbial keratinases and their production and applications. Appl Microbiol Biotechnol, 85, 1735–50
   PubMed Web of Science ®Google Scholar
• Burtt EH, Ichida JM. (1999a). Bacteria useful for degrading keratin. US Patent N° 6214676
   Google Scholar
• Burtt EH, Ichida JM. (1999b). Keratinase produced by Bacillus licheniformis. US Patent N° 5877000
   Google Scholar
• Cai CG, Lou BG, Zheng XD. (2008). Keratinase production and keratin degradation by a mutant strain of Bacillus subtilis. J Zhejiang Univ Sci B, 9, 60–7
   PubMed Web of Science ®Google Scholar
• Cai CG, Zheng XD. (2009). Medium optimization for keratinase production in hair substrate by a new Bacillus subtilis KD-N2 using response surface methodology. J Ind Microbiol Biotechnol, 36, 875–83
   PubMed Web of Science ®Google Scholar
• Cai SB, Huang ZH, Zhang XQ, et al. (2011). Identification of a keratinase-producing bacterial strain and enzymatic study for its improvement on shrink resistance and tensile strength of wool- and polyester-blended fabric. Appl Biochem Biotechnol, 163, 112–26
   PubMed Web of Science ®Google Scholar
• Casarin F, Cladera-Olivera F, Brandelli A. (2008). Use of poultry byproduct for production of keratinolytic enzymes. Food Bioprocess Technol, 1, 301–5
   Web of Science ®Google Scholar
• Cedrola SML, Melo ACN, Mazotto AM, et al. (2012). Keratinases and sulfide from Bacillus subtilis SLC to recycle feather waste. World J Microbiol Biotechnol, 28, 1259–69
   PubMed Web of Science ®Google Scholar
• Chao YP, Xie FH, Yang J, et al. (2007). Screening for a new Streptomyces strain capable of efficient keratin degradation. J Environ Sci, 19, 1125–8
   Google Scholar
• Corrêa APF, Daroit DJ, Coelho JG, et al. (2011). Antioxidant, antihypertensive and antimicrobial properties of ovine milk caseinate hydrolyzed with a microbial protease. J Sci Food Agric, 91, 2247–54
   PubMed Web of Science ®Google Scholar
• Cortezi M, Cilli EM, Contiero J. (2008). Bacillus amyloliquefaciens: a new keratinolytic feather-degrading bacteria. Curr Trends Biotechnol Pharm, 2, 170–7
   Google Scholar
• Coulombe PA, Omary MB. (2002). “Hard” and “soft” principles defining the structure, function and regulation of keratin intermediate filaments. Curr Opin Cell Biol, 14, 110–22
   PubMed Web of Science ®Google Scholar
• Coward-Kelly G, Agbogbo FK, Holtzapple MT. (2006). Lime treatment of keratinous materials for the generation of highly digestible animal feed: 2. Animal hair. Bioresour Technol, 97, 1344–1352
   PubMed Web of Science ®Google Scholar
• Daroit DJ, Corrêa APF, Brandelli A. (2009). Keratinolytic potential of a novel Bacillus sp. P45 isolated from the Amazon basin fish Piaractus mesopotamicus. Int Biodeterior Biodegrad, 63, 358–63
   Web of Science ®Google Scholar
• Daroit DJ, Corrêa APF, Segalin J, Brandelli A. (2010). Characterization of a keratinolytic protease produced by the feather-degrading Amazonian bacterium Bacillus sp. P45. Biocatal Biotransform, 28, 370–9
   Web of Science ®Google Scholar
• Daroit DJ, Sant’Anna V, Brandelli A. (2011a). Kinetic stability modelling of keratinolytic protease P45: influence of temperature and metal ions. Appl Biochem Biotechnol, 165, 1740–53
   PubMed Web of Science ®Google Scholar
• Daroit DJ, Corrêa APF, Brandelli A. (2011b). Production of keratinolytic proteases through bioconversion of feather meal by the Amazonian bacterium Bacillus sp. P45. Int Biodeterior Biodegrad, 65, 45–51
   Web of Science ®Google Scholar
• Daroit DJ, Corrêa APF, Canales MM, et al. (2012). Physicochemical properties and biological activities of ovine caseinate hydrolysates. Dairy Sci Technol, 92, 335–51
   Web of Science ®Google Scholar
• Duarte TR, Oliveira SS, Macrae A, et al. (2011). Increased expression of keratinase and other peptidases by Candida parapsilosis mutants. Braz J Med Biol Res, 44, 212–16
   Google Scholar
• El-Bondkly AM, El-Gendy MMA. (2010). Keratinolytic activity from new recombinant fusant AYA2000, derived from endophytic Micromonospora strains. Can J Microbiol, 56, 748–60
   PubMed Web of Science ®Google Scholar
• El-Gendy MMA. (2010). Keratinase production by endophytic Penicillium spp. Morsy1 under solid-state fermentation using rice straw. Appl Biochem Biotechnol, 162, 780–94
   PubMed Web of Science ®Google Scholar
• Embaby AM, Zaghloul TI, Elmahdy AR. (2010). Optimizing the biodegradation of two keratinous wastes through a Bacillus subtilis recombinant strain using a response surface methodology. Biodegradation, 21, 1077–92
   PubMed Web of Science ®Google Scholar
• Fakhfakh N, Kanoun S, Manni L, Nasri M. (2009). Production and biochemical and molecular characterization of a keratinolytic serine protease from chicken feather-degrading Bacillus licheniformis RPk. Can J Microbiol, 55, 427–36
   PubMed Web of Science ®Google Scholar
• Fakhfakh N, Ktari N, Haddar A, et al. (2011). Total solubilisation of the chicken feathers by fermentation with a keratinolytic bacterium, Bacillus pumilus A1, and the production of protein hydrolysate with high antioxidative activity. Process Biochem, 46, 1731–7
   Web of Science ®Google Scholar
• Fakhfakh-Zouari N, Haddar A, Hmidet N, et al. (2010). Application of statistical experimental design for optimization of keratinases production by Bacillus pumilus A1 grown on chicken feather and some biochemical properties. Process Biochem, 45, 617–26
   Web of Science ®Google Scholar
• Fisher SH. (1999). Regulation of nitrogen metabolism in Bacillus subtilis: vive la différence! Mol Microbiol, 32, 223–32
   PubMed Web of Science ®Google Scholar
• Fisher KE, Ruan B, Alexander PA, et al. (2007). Mechanism of the kinetically-controlled folding reaction of subtilisin. Biochemistry, 46, 640–51
   PubMed Web of Science ®Google Scholar
• Fraser RDB, Parry DAD. (2008). Molecular packing in the feather keratin filament. J Struct Biol, 162, 1–13
   PubMed Web of Science ®Google Scholar
• Giongo JL, Lucas FS, Casarin F, et al. (2007). Keratinolytic proteases of Bacillus species isolated from the Amazon basin showing remarkable de-hairing activity. World J Microbiol Biotechnol, 23, 375–82
   Web of Science ®Google Scholar
• Gioppo NMR, Moreira-Gasparin FG, Costa AM, et al. (2009). Influence of the carbon and nitrogen sources on keratinase production by Myrothecium verrucaria in submerged and solid state cultures. J Ind Microbiol Biotechnol, 36, 705–11
   PubMed Web of Science ®Google Scholar
• Görke B, Stülke J. (2008). Carbon catabolite repression in bacteria: many ways to make the most out of nutrients. Nature Rev Microbiol, 6, 613–24
   PubMed Web of Science ®Google Scholar
• Gradisar H, Friedrich J, Krizaj I, Jerala R. (2005). Similarities and specificities of fungal keratinolytic proteases: comparison of keratinases of Paecilomyces marquandii and Doratomyces microsporus to some known proteases. Appl Environ Microbiol, 71, 3420–6
   PubMed Web of Science ®Google Scholar
• Grazziotin A, Pimentel FA, De Jong EV, Brandelli A. (2008). Poultry feather hydrolysate as a protein source for growing rats. Braz J Vet Res Anim Sci, 45, 61–7
   Google Scholar
• Gupta R, Beg QK, Lorenz P. (2002a). Bacterial alkaline proteases: molecular approaches and industrial applications. Appl Microbiol Biotechnol, 59, 15–32
   PubMed Web of Science ®Google Scholar
• Gupta R, Beg QK, Khan S, Chauhan B. (2002b). An overview on fermentation, downstream processing and properties of microbial alkaline proteases. Appl Microbiol Biotechnol, 60, 381–95
   PubMed Web of Science ®Google Scholar
• Gupta R, Ramnani P. (2006). Microbial keratinases and their prospective applications: an overview. Appl Microbiol Biotechnol, 70, 21–33
   PubMed Web of Science ®Google Scholar
• Gupta R, Sharma R, Beg QK. (2012). Revisiting microbial keratinases: next generation proteases for sustainable biotechnology. Crit Rev Biotechnol, 33, 216--228
   Google Scholar
• Haddar HO, Zaghloul TI, Saeed HM. (2009). Biodegradation of native feather keratin by Bacillus subtilis recombinant strains. Biodegradation, 20, 687–94
   PubMed Web of Science ®Google Scholar
• Hidalgo ME, Daroit DJ, Corrêa APF, et al. (2012). Physicochemical and antioxidant properties of bovine caseinate hydrolysates obtained through microbial protease treatment. Int J Dairy Technol, 65, 342–52
   Web of Science ®Google Scholar
• Jan J, Valle F, Bolivar F, Merino E. (2000). Characterization of the 5’ subtilisin (aprE) regulatory region from Bacillus subtilis. FEMS Microbiol Lett, 183, 9–14
   PubMed Web of Science ®Google Scholar
• Jaouadi B, Ellouz-Chaabouni S, Ben Ali M, et al. (2009). Excellent laundry detergent compatibility and high dehairing ability of the Bacillus pumilus CBS alkaline proteinase (SAPB). Biotechnol Bioprocess Eng, 14, 503–12
   Web of Science ®Google Scholar
• Jeong JH, Jeon YD, Lee OM, et al. (2010a). Characterization of a multifunctional feather-degrading Bacillus subtilis isolated from forest soil. Biodegradation, 21, 1029–40
   PubMed Web of Science ®Google Scholar
• Jeong JH, Lee OM, Jeon YD, et al. (2010b). Production of keratinolytic enzyme by a newly isolated feather-degrading Stenotrophomonas maltophilia that produces plant growth-promoting activity. Process Biochem, 45, 1738–45
   Web of Science ®Google Scholar
• Jeong JH, Park KH, Oh DJ, et al. (2010c). Keratinolytic enzyme-mediated biodegradation of recalcitrant feather by a newly isolated Xanthomonas sp. P5. Polym Degrad Stabil, 95, 1969–77
   Web of Science ®Google Scholar
• Johannes TW, Zhao H. (2006). Directed evolution of enzymes and biosynthetic pathways. Curr Opin Microbiol, 9, 261–67
   PubMed Web of Science ®Google Scholar
• Joo HS, Chang CS. (2005). Production of protease from a new alkalophilic Bacillus sp. I-312 grown on soybean meal: optimization and some properties. Process Biochem, 40, 1263–70
   Web of Science ®Google Scholar
• Kalil SJ, Maugeri F, Rodrigues MI. (2000). Response surface analysis and simulation as a tool for bioprocess design and optimization. Process Biochem, 35, 539–50
   Web of Science ®Google Scholar
• Khardenavis AA, Kapley A, Purohit HJ. (2009). Processing of poultry feathers by alkaline keratin hydrolyzing enzyme from Serratia sp. HPC 1383. Waste Manage, 29, 1409–15
   PubMed Web of Science ®Google Scholar
• Kim JM, Choi YM, Suh HJ. (2005). Preparation of feather digests as fertilizer with Bacillus pumilis KHS-1. J Microbiol Biotechnol, 15, 472–76
   Web of Science ®Google Scholar
• Kita DA, Routien JB. (1965). Process of producing keratinase. US Patent N° 3173847
   Google Scholar
• Kolkman MAB, van der Ploeg R, Bertels M, et al. (2008). The twin-arginine signal peptide of Bacillus subtilis YwbN can direct either Tat- or Sec-dependent secretion of different cargo proteins: secretion of active subtilisin via the B. subtilis Tat pathway. Appl Environ Microbiol, 74, 7507–13
   PubMed Web of Science ®Google Scholar
• Korniłłowicz-Kowalska T. (1997). Studies on the decomposition of keratin wastes by saprotrophic microfungi: I: criteria for evaluating keratinolytic activity. Acta Mycol, 32, 51–79
   Google Scholar
• Korniłłowicz-Kowalska T, Bohacz J. (2011). Biodegradation of keratin waste: theory and practical aspects. Waste Manage, 31, 1689–701
   PubMed Web of Science ®Google Scholar
• Kumar A, Singh S. (2012). Directed evolution: tailoring biocatalysts for industrial applications. Crit Rev Biotechnol, doi:10.3109/07388551.2012.716810
   Google Scholar
• Kumar CG, Takagi H. (1999). Microbial alkaline proteases: from a bioindustrial viewpoint. Biotechnol Adv, 17, 561–94
   PubMed Web of Science ®Google Scholar
• Kumar R, Balaji S, Uma TS, Mandal AB, Sehgal PK. (2010). Optimization of influential parameters for extracellular keratinase production by Bacillus subtilis (MTCC9102) in solid state fermentation using horn meal – a biowaste management. Appl Biochem Biotechnol, 160, 30–9
   PubMed Web of Science ®Google Scholar
• Lee YJ, Kim JH, Kim HK, Lee JS. (2004). Production and characterization of keratinase from Paracoccus sp. WJ-98. Biotechnol Bioprocess Eng, 9, 17–22
   Web of Science ®Google Scholar
• Li J, Shi PJ, Han XY, et al. (2007). Functional expression of the keratinolytic serine protease gene sfp2 from Streptomyces fradiae var. k11 in Pichia pastoris. Protein Expres Purif, 54, 79–86
   PubMed Web of Science ®Google Scholar
• Liang X, Bian Y, Tang XF, et al. (2010). Enhancement of keratinolytic activity of a thermophilic subtilase by improving its autolysis resistance and thermostability under reducing conditions. Appl Microbiol Biotechnol, 87, 999–1006
   PubMed Web of Science ®Google Scholar
• Liang JD, Han YF, Zhang JW, et al. (2011). Optimal culture conditions for keratinase production by a novel thermophilic Myceliophthora thermophila strain GZUIFR-H49-1. J Appl Microbiol, 110, 871–80
   PubMed Web of Science ®Google Scholar
• Lin X, Kelemen DW, Miller ES, Shih JCH. (1995). Nucleotide sequence and expression of kerA, the gene encoding a keratinolytic protease of Bacillus licheniformis PWD-1. Appl Environ Microbiol, 61, 1469–74
   PubMed Web of Science ®Google Scholar
• Lin X, Wong SL, Miller ES, Shih JCH. (1997). Expression of the Bacillus licheniformis PWD-1 keratinase gene in B. subtilis. J Ind Microbiol Biotechnol, 19, 134–8
   PubMed Web of Science ®Google Scholar
• Lin HH, Yin LJ, Jiang ST. (2009a). Cloning, expression, and purification of Pseudomonas aeruginosa keratinase in Escherichia coli AD494(DE3)pLysS expression system. J Agric Food Chem, 57, 3506–11
   PubMed Web of Science ®Google Scholar
• Lin HH, Yin LJ, Jiang ST. (2009b). Expression and purification of Pseudomonas aeruginosa keratinase in Bacillus subtilis DB104 expression system. J Agric Food Chem, 57, 7779–84
   PubMed Web of Science ®Google Scholar
• Lin HH, Yin LJ, Jiang ST. (2009c). Functional expression and characterization of keratinase from Pseudomonas aeruginosa in Pichia pastoris. J Agric Food Chem, 57, 5321–5
   PubMed Web of Science ®Google Scholar
• Lin HH, Yin LJ. (2010). Feather meal and rice husk enhanced keratinases production by Bacillus licheniformis YJ4 and characters of produced keratinases. J Mar Sci Technol, 18, 458–65
   Web of Science ®Google Scholar
• Lopes FC, Silva LAD, Tichota DM, et al. (2011). Production of proteolytic enzymes by a keratin-degrading Aspergillus niger. Enzyme Res 2011: article ID 487093, 9 pp
   Google Scholar
• Lv LX, Sim MH, Li YD, et al. (2010). Production, characterization and application of a keratinase from Chryseobacterium L99 sp. nov. Process Biochem, 45, 1236–44
   Web of Science ®Google Scholar
• Mabrouk MEM. (2008). Feather degradation by a new keratinolytic Streptomyces sp. MS-2. World J Microbiol Biotechnol, 24, 2331–8
   Web of Science ®Google Scholar
• Mäder U, Antelmann H, Buder T, et al. (2002). Bacillus subtilis functional genomics: genome-wide analysis of the DegS-DegU regulon by transcriptomics and proteomics. Mol Genet Genomics, 268, 455–67
   PubMed Web of Science ®Google Scholar
• Manczinger L, Rozs M, Cs V, Kevei F. (2003). Isolation and characterization of a new keratinolytic Bacillus licheniformis strain. World J Microbiol Biotechnol, 19, 35–9
   Web of Science ®Google Scholar
• Mandenius CF, Brundin A. (2008). Bioprocess optimization using design-of-experiments methodology. Biotechnol Prog, 24, 1191–203
   PubMed Web of Science ®Google Scholar
• Mazotto AM, Cedrola SML, Lins U, et al. (2010). Keratinolytic activity of Bacillus subtilis AMR using human hair. Lett Appl Microbiol, 50, 89–96
   PubMed Web of Science ®Google Scholar
• Meng K, Li J, Cao Y, et al. (2007). Gene cloning and heterologous expression of a serine protease from Streptomyces fradiae var. k11. Can J Microbiol, 53, 186–95
   PubMed Web of Science ®Google Scholar
• Mitola G, Escalona F, Salas R, et al. (2002). Morphological characterization of in-vitro human hair keratinolysis, produced by identified wild strains of Chrysosporium species. Mycopathologia, 156, 163–9
   PubMed Web of Science ®Google Scholar
• Mitsuiki S, Sakai M, Moriyama Y, et al. (2002). Purification and some properties of keratinolytic enzyme from an alkaliphilic Nocardiopsis sp. TOA-1. Biosci Biotechnol Biochem, 66, 164–7
   PubMed Web of Science ®Google Scholar
• Mitsuiki S, Hui Z, Matsumoto D, et al. (2006). Degradation of PrPSc by keratinolytic protease from Nocardiopsis sp. TOA-1. Biosci Biotechnol Biochem, 70, 1246–8
   PubMed Web of Science ®Google Scholar
• Mohorcic M, Torkar A, Friedrich J, et al. (2007). An investigation into keratinolytic enzymes to enhance ungual drug delivery. Int J Pharm, 332, 196–201
   PubMed Web of Science ®Google Scholar
• Moreno MS, Schneider BL, Maile RR, et al. (2001). Catabolite repression mediated by the CcpA protein in Bacillus subtilis: novel modes of regulation revealed by whole-genome analyses. Mol Microbiol, 39, 1366–81
   PubMed Web of Science ®Google Scholar
• Mukherjee AK, Rai SK, Bordoloi NK. (2011). Biodegradation of waste chicken-feathers by an alkaline b-keratinase (Mukartinase) purified from a mutant Brevibacillus sp. strain AS-S10-II. Int Biodeterior Biodegrad, 65, 1229–37
   Web of Science ®Google Scholar
• Ni H, Chen QH, Chen F, et al. (2011). Improved keratinase production for feather degradation by Bacillus licheniformis ZJUEL31410 in submerged cultivation. Afr J Biotechnol, 10, 7236–44
   Google Scholar
• Noronha EF, Lima BD, Sá CM, Felix CR. (2002). Heterologous production of Aspergillus fumigatus keratinase in Pichia pastoris. World J Microbiol Biotechnol, 18, 563–8
   Web of Science ®Google Scholar
• Noval JJ, Nickerson WJ. (1959). Decomposition of native keratin by Streptomyces fradiae. J Bacteriol, 77, 251–63
   PubMed Web of Science ®Google Scholar
• Odetallah NH, Wang JJ, Garlich JD, Shih JCH. (2003). Keratinase in starter diets improves growth of broiler chicks. Poultry Sci, 82, 664–70
   PubMed Web of Science ®Google Scholar
• Onifade AA, Al-Sane NA, Al-Musallam AA, Al-Zarban S. (1998). A review: potentials for biotechnological applications of keratin-degrading microorganisms and their enzymes for nutritional improvement of feathers and other keratins as livestock feed resources. Bioresour Technol, 66, 1–11
   Web of Science ®Google Scholar
• Park GT, Son HJ. (2009). Keratinolytic activity of Bacillus megaterium F7-1, a feather-degrading mesophilic bacterium. Microbiol Res, 164, 478–85
   PubMed Web of Science ®Google Scholar
• Pillai P, Mandge S, Archana G. (2011). Statistical optimization of production and tannery applications of a keratinolytic serine protease from Bacillus subtilis P13. Process Biochem, 46, 1110–17
   Web of Science ®Google Scholar
• Poole AJ, Church JS, Huson MG. (2009). Environmentally sustainable fibers from regenerated protein. Biomacromolecules, 10, 1–8
   PubMed Web of Science ®Google Scholar
• Porres JM, Benito MJ, Lei XG. (2002). Functional expression of keratinase (kerA) gene from Bacillus licheniformis in Pichia pastoris. Biotechnol Lett, 24, 631–6
   Web of Science ®Google Scholar
• Prakash P, Jayalakshmi SK, Sreeramulu K. (2010a). Production of keratinase by free and immobilized cells of Bacillus halodurans strain PPKS-2: partial characterization and its application in feather degradation and dehairing of the goat skin. Appl Biochem Biotechnol, 160, 1909–20
   PubMed Web of Science ®Google Scholar
• Prakash P, Jayalakshmi S, Sreeramulu K. (2010b). Purification and characterization of extreme alkaline, thermostable keratinase, and keratin disulfide reductase produced by Bacillus halodurans PPKS-2. Appl Microbiol Biotechnol, 87, 625–33
   PubMed Web of Science ®Google Scholar
• Priest FG. (1977). Extracellular enzyme synthesis in the genus Bacillus. Bacteriol Rev, 41, 711–53
   PubMedGoogle Scholar
• Radha S, Gunasekaran P. (2007). Cloning and expression of keratinase gene in Bacillus megaterium and optimization of fermentation conditions for the production of keratinase by recombinant strain. J Appl Microbiol, 103, 1301–10
   PubMed Web of Science ®Google Scholar
• Radha S, Gunasekaran P. (2008). Sustained expression of keratinase gene under PxylA and PamyL promoters in the recombinant Bacillus megaterium MS941. Bioresour Technol, 99, 5528–37
   Google Scholar
• Radha S, Gunasekaran P. (2009). Purification and characterization of keratinase from recombinant Pichia and Bacillus strains. Protein Expres Purif, 64, 24–31
   PubMed Web of Science ®Google Scholar
• Rahayu S, Syah D, Suhartono MT. (2012). Degradation of keratin by keratinase and disulfide reductase from Bacillus sp. MTS of Indonesian origin. Biocatal Agric Biotechnol, 1, 152–8
   Google Scholar
• Rai SK, Konwarh R, Mukherjee AK. (2009). Purification, characterization and biotechnological application of an alkaline β-keratinase produced by Bacillus subtilis RM-01 in solid-state fermentation using chicken-feather as substrate. Biochem Eng J, 45, 218–25
   Web of Science ®Google Scholar
• Rai SK, Mukherjee AK. (2011). Optimization of production of an oxidant and detergent-stable alkaline β-keratinase from Brevibacillus sp. strain AS-S10-II: application of enzyme in laundry detergent formulations and in leather industry. Biochem Eng J, 54, 47–56
   Web of Science ®Google Scholar
• Rajput R, Sharma R, Gupta R. (2011). Cloning and characterization of a thermostable detergent-compatible recombinant keratinase from Bacillus pumilus KS12. Biotechnol Appl Biochem, 58, 109–18
   Web of Science ®Google Scholar
• Rajput R, Tiwary E, Sharma R, Gupta R. (2012). Swapping of pro-sequences between keratinases of Bacillus licheniformis and Bacillus pumilus: altered substrate specificity and thermostability. Enzyme Microb Technol, 51, 131–8
   PubMed Web of Science ®Google Scholar
• Ramnani P, Singh R, Gupta R. (2005). Keratinolytic potential of Bacillus licheniformis RG1: structural and biochemical mechanism of feather degradation. Can J Microbiol, 51, 191–6
   PubMed Web of Science ®Google Scholar
• Rao MB, Tanksale AM, Ghatge MS, Deshpande VV. (1998). Molecular and biotechnological aspects of microbial proteases. Microbiol Mol Biol Rev, 62, 597–635
   PubMed Web of Science ®Google Scholar
• Riffel A, Daroit DJ, Brandelli A. (2011). Nutritional regulation of protease production by the feather–degrading bacterium Chryseobacterium sp. kr6. New Biotechnol, 28, 153–7
   PubMed Web of Science ®Google Scholar
• Rondon MR, August PR, Bettermann AD, et al. (2000). Cloning the soil metagenome: a strategy for accessing the genetic and functional diversity of uncultured microorganisms. Appl Environ Microbiol, 66, 2541–7
   PubMed Web of Science ®Google Scholar
• Rouse JG, Van Dyke ME. (2010). A review of keratin-based biomaterials for biomedical applications. Materials, 3, 999–1014
   Web of Science ®Google Scholar
• Saber WIA, El-Metwally MM, El-Hersh MS. (2010). Keratinase production and biodegradation of some keratinous wastes by Alternaria tenuissima and Aspergillus nidulans. Res J Microbiol, 5, 21–35
   Google Scholar
• Sanchez S, Demain AL. (2011). Enzymes and bioconversions of industrial, pharmaceutical, and biotechnological significance. Org Process Res Dev, 15, 224–30
   Web of Science ®Google Scholar
• Sharma R, Gupta R. (2010a). Substrate specificity characterization of a thermostable keratinase from Pseudomonas aeruginosa KS-1. J Ind Microbiol Biotechnol, 37, 785–92
   PubMed Web of Science ®Google Scholar
• Sharma R, Gupta R. (2010b). Extracellular expression of keratinase Ker P from Pseudomonas aeruginosa in E. coli. Biotechnol Lett, 32, 1863–8
   PubMed Web of Science ®Google Scholar
• Sharma R, Gupta R. (2012). Coupled action of γ-glutamyl transpeptidase-glutathione and keratinase effectively degrades feather keratin and surrogate prion protein, Sup 35NM. Bioresour Technol, 120, 314–17
   PubMed Web of Science ®Google Scholar
• Shih JCH. (2003). Composition and method for destruction of infectious prion proteins. US Patent N° 6613505
   Google Scholar
• Shih JCH, Williams CM. (1992). Purified Bacillus licheniformis PWD-1 keratinase. US Patent N° 5171682
   Google Scholar
• Shih JCH, Wang JJ. (2006). Keratinase technology: from feather degradation and feed additive, to prion destruction. CAB Rev Perspect Agric Vet Sci Nutr Nat Resour, 1, article 042, 6 pp
   Google Scholar
• Shrinivas D, Naik GR. (2011). Characterization of alkaline thermostable keratinolytic protease from thermoalkalophilic Bacillus halodurans JB 99 exhibiting dehairing activity. Int Biodeterior Biodegrad, 65, 29–35
   Web of Science ®Google Scholar
• Singh CJ. (2002). Optimization of an extracellular protease of Chrysosporium keratinophilum and its potential in bioremediation of keratinic wastes. Mycopathologia, 156, 151–6
   PubMed Web of Science ®Google Scholar
• Singh BK. (2010). Exploring microbial diversity for biotechnology: the way forward. Trends Biotechnol, 28, 111–16
   PubMed Web of Science ®Google Scholar
• Son HJ, Park HC, Kim HS, Lee CY. (2008). Nutritional regulation of keratinolytic activity in Bacillus pumilis. Biotechnol Lett, 30, 461–5
   PubMed Web of Science ®Google Scholar
• Sonenshein AL. (2005). CodY, a global regulator of stationary phase and virulence in Gram–positive bacteria. Curr Opin Microbiol, 8, 203–7
   PubMed Web of Science ®Google Scholar
• Strauch MA, Hoch JA. (1993). Transition-state regulators: sentinels of Bacillus subtilis post-exponential gene expression. Mol Microbiol, 7, 337–42
   PubMed Web of Science ®Google Scholar
• Sumantha A, Larroche C, Pandey A. (2006). Microbiology and industrial biotechnology of food-grade proteases: a perspective. Food Technol Biotechnol, 44, 211–20
   Web of Science ®Google Scholar
• Suntornsuk W, Suntornsuk L. (2003). Feather degradation by Bacillus sp. FK 46 in submerged cultivation. Bioresour Technol, 86, 239–43
   PubMed Web of Science ®Google Scholar
• Suzuki Y, Tsujimoto Y, Matsui H, Watanabe K. (2006). Decomposition of extremely hard-to-degrade animal proteins by thermophilic bacteria. J Biosci Bioeng, 102, 73–81
   PubMed Web of Science ®Google Scholar
• Takahashi K, Yamamoto H, Yokote Y, Hattori M. (2004). Thermal behavior of fowl feather keratin. Biosci Biotechnol Biochem, 68, 1875–81
   PubMed Web of Science ®Google Scholar
• Tang WL, Zhao H. (2009). Industrial biotechnology: tools and applications. Biotechnol J, 4, 1725–39
   PubMedGoogle Scholar
• Tatineni R, Doddapaneni KK, Potumarthi RC, Mangamoori LN. (2007). Optimization of keratinase production and enzyme activity using response surface methodology with Streptomyces sp7. Appl Biochem Biotechnol, 141, 187–201
   PubMed Web of Science ®Google Scholar
• Thys RCS, Guzzon SO, Cladera-Olivera F, Brandelli A. (2006). Optimization of protease production by Microbacterium sp. in feather meal using response surface methodology. Process Biochem, 41, 67–73
   Web of Science ®Google Scholar
• Tiwary E, Gupta R. (2010a). Extracellular expression of keratinase from Bacillus licheniformis ER-15 in Escherichia coli. J Agric Food Chem, 58, 8380–5
   PubMed Web of Science ®Google Scholar
• Tiwary E, Gupta R. (2010b). Medium optimization for a novel 58 kDa dimeric keratinase from Bacillus licheniformis ER-15: biochemical characterization and application in feather degradation and dehairing of hides. Bioresour Technol, 101, 6103–10
   PubMed Web of Science ®Google Scholar
• Van Beilen JB, Li Z. (2002). Enzyme technology: an overview. Curr Opin Biotechnol, 13, 338–44
   PubMed Web of Science ®Google Scholar
• Vasconcelos A, Freddi G, Cavaco-Paulo A. (2008). Biodegradable materials based on silk fibroin and keratin. Biomacromolecules, 9, 1299–305
   PubMed Web of Science ®Google Scholar
• Vasileva-Tonkova E, Gousterova A, Neshev G. (2009). Ecologically safe method for improved feather wastes biodegradation. Int Biodeterior Biodegrad, 63, 1008–12
   Web of Science ®Google Scholar
• Veselá M, Friedrich J. (2009). Amino acid and soluble protein cocktail from waste keratin hydrolysed by a fungal keratinase of Paecilomyces marquandii. Biotechnol Bioprocess Eng, 14, 84–90
   Web of Science ®Google Scholar
• Vignardet C, Guillaume YC, Michel L, et al. (2001). Comparison of two hard keratinous substrates submitted to the action of a keratinase using an experimental design. Int J Pharm, 224, 115–22
   PubMed Web of Science ®Google Scholar
• Voigt B, Schweder T, Sibbald MJJB, et al. (2006). The extracellular proteome of Bacillus licheniformis grown in different media and under different nutrient starvation conditions. Proteomics, 6, 268–81
   PubMed Web of Science ®Google Scholar
• Voigt B, Hoi LT, Jürgen B, et al. (2007). The glucose and nitrogen starvation response of Bacillus licheniformis. Proteomics, 7, 413–23
   PubMed Web of Science ®Google Scholar
• Wang JJ, Rojanatavorn K, Shih JCH. (2004). Increased production of Bacillus keratinase by chromosomal integration of multiple copies of the kerA gene. Biotechnol Bioeng, 87, 459–64
   PubMed Web of Science ®Google Scholar
• Wang JJ, Greenhut WB, Shih JCH. (2005). Development of an asporogenic Bacillus licheniformis for the production of keratinase. J Appl Microbiol, 98, 761–7
   PubMed Web of Science ®Google Scholar
• Wang JJ, Garlich JD, Shih JCH. (2006). Beneficial effects of Versazyme, a keratinase feed additive, on body weight, feed conversion, and breast yield of broiler chickens. J Appl Poultry Res, 15, 544–50
   Web of Science ®Google Scholar
• Wang H, Guo Y, Shih JCH. (2008a). Effects of dietary supplementation of keratinase on growth performance, nitrogen retention and intestinal morphology of broiler chickens fed diets with soybean and cottonseed meals. Anim Feed Sci Technol, 140, 376–84
   Web of Science ®Google Scholar
• Wang SL, Hsu WT, Liang TW, et al. (2008b). Purification and characterization of three novel keratinolytic metalloproteases produced by Chryseobacterium indologenes TKU014 in a shrimp shell powder medium. Bioresour Technol, 99, 5679–86
   PubMed Web of Science ®Google Scholar
• Xie F, Chao Y, Yang X, et al. (2010). Purification and characterization of four keratinases produced by Streptomyces sp. strain 16 in native human foot skin medium. Bioresour Technol, 101, 344–50
   PubMed Web of Science ®Google Scholar
• Yamamura S, Morita Y, Hasan Q, et al. (2002a). Keratin degradation: a cooperative action of two enzymes from Stenotrophomonas sp. Biochem Biophys Res Commun, 294, 1138–43
   PubMed Web of Science ®Google Scholar
• Yamamura S, Morita Y, Hasan Q, et al. (2002b). Characterization of a new keratin-degrading bacterium isolated from deer fur. J Biosci Bioeng, 93, 595–600
   PubMed Web of Science ®Google Scholar
• Yang JI, Kuo JM, Chen WM, et al. (2011). Feather keratin hydrolysis by an aquatic bacterium Meiothermus I40 from hot spring water. Int J Food Eng, 7, article 17, 23 pp
   Google Scholar
• Yoshioka M, Miwa T, Horii H, et al. (2007). Characterization of a proteolytic enzyme derived from a Bacillus strain that effectively degrades prion protein. J Appl Microbiol, 102, 509–15
   PubMed Web of Science ®Google Scholar
• Zaghloul TI. (1998). Cloned Bacillus subtilis alkaline protease (aprA) gene showing high level of keratinolytic activity. Appl Biochem Biotechnol, 70–2, 199–205
   Web of Science ®Google Scholar
• Zeng YH, Shen FT, Tan CC, et al. (2011). The flexibility of UV-inducible mutation in Deinococcus ficus as evidenced by the existence of the imuB.dnaE2 gene cassette and generation of superior feather degrading bacteria. Microbiol Res, 167, 40–7
   PubMed Web of Science ®Google Scholar
• Zhang B, Jiang DD, Zhou WW, et al. (2009). Isolation and characterization of a new Bacillus sp. 50-3 with highly alkaline keratinase activity from Calotes versicolor faeces. World J Microbiol Biotechnol, 25, 583–90
   Web of Science ®Google Scholar