Feather Meal Agar Research Articles

Isolation and screening of keratinolytic bacteria from feather dumping soil near in Lucknow and Kanpur city, North region of Indian

Background Keratinases are proteolytic enzymes that have the capability of degrading insoluble keratin substrates. LS4, LS5, and KS3 were newly isolated strains showing ability to hydrolyze keratins and keratin based products. Objective In this study, different bacterial strains were isolated from soil, screened for protease and keratinase production, and the best isolates were identified. Methods Serial dilution and plating method were used for isolation of pure bacterial culture. Isolated, 48 strains were screened, and their feather degrading ability on feather meal agar plates and keratin azure-based agar. The proteolytic activity of the isolates was also screened on casein agar. Results Three strains; LS4, LS5, and KS3 shows keratinolytic activity that reveal the keratinase enzyme on medium; feather meal agar, keratin azure agar, and casein agar. Among all the three strains (LS4, LS5, and KS3), KS3 show largest inhibition zone that show maximum enzymatic activity. For its characterization 16S RNA was performed, sequence KS3 was submitted to GenBank and was identified as Bacillus tropicus KS3. Newly isolated strain B. tropicus KS3 showed the keratinase production and highest keratinase activity (35.06 ± 2.5 U/ml). B. tropicus KS3 also show the highest degradation of feather efficiently showed 84% of whole chicken feather biodegradation at 37 °C within 15 days among all the isolated strains. Conclusion Keratinase enzyme possesses a wide range of potential applications in the bioremediation of feather waste and bio-fertilizer in agricultural land. The industry demands a better source of this enzyme due to its multivariate application and huge market demand. In the present study, a novel keratinase-producing bacteria was isolated and characterized as Bacillus tropicus KS3 from poultry waste contamination soil.

Keratinase of Bacillus cereus Lr3/2 KP015746 from deteriorated leather samples

Keratin is an insoluble fibrous protein found in hair, wool, feather, nail, horns and other epithelial covering. The high resistance of keratin to proteases is due to its densely packed and strongly stabilized by several hydrogen bonds and hydrophobic interactions, in addition to several disulfide bonds. A keratinase enzyme is useful for biotechnological purposes, and also for hydrolysis of de-hairing of bovine hides, poultry feathers, and leather surplus. In the present study, B. cereus KJ72442 was isolated from deteriorated leather samples using feather meal as a substrate and identified by 16SrDNA sequencing and with accession number B. cereus Lr3/2 KP015746). The colony showing the highest zone of keratin hydrolysis on feather meal agar was selected for keratinase production. B. cereus showed efficient keratinase production 41.06±2U/ml at optimum temperature of 37°C and pH 7 after 72h using 1% feather meal as a substrate. B. cereus keratinolytic activity was found to be metalloprotease, as inhibited by 1mM EDTA but not by PMSF.In addition to keratinase, B. cereus KP015746 (Lr3/2) was also proficiently found to produce collagenase, caseinase and gelatinase. On the lab scale, the efficiency of B. cereus Lr3/2 KP015746 keratinase to degrade leather was analyzed and observed excellent results. Hence, the experimental outcome revealed that B.cereus KP015746 (Lr3/2) can be effectively used to treat keratin, collagen rich agro industrial waste ecofriendly.

CHICKEN FEATHER DEGRADATION BY KERATINOLYTIC ASPERGILLUS SPECIES ISOLATED FROM FEATHER WASTE DUMPING SOIL

Slaughterhouses and poultry processing units worldwide dispose of huge amount of chicken feathers that accumulate as solid waste in the environment and cause serious consequences. Keratinases are a group of enzymes, produced by microorganisms have the ability to degrade tough recalcitrant keratin that is abundantly present in chicken feathers. Soil sample was collected from a feather dumping site at Virudhunagar (9° 35' 13.9524'’ N Latitude and 77° 57' 5.1516'’ E Longitude), Tamil Nadu, India. Soil sample was serially diluted, inoculated on to feather meal agar plates and incubated at 37 °C for 7 days to isolate keratinolytic fungal strains. The isolated strains were screened for proteolytic activity on skim milk agar for 8 days and three better strains were identified based on morphology, mycelial growth, and structure of hyphae using lactophenol cotton blue staining and confirmed by ITS primer sequencing method as Aspergillus niger, Aspergillus terreus and Aspergillus flavus respectively. Different range of pH (7 to 11), temperature (25 to 45 °C), substrate (bovine serum albumin, feather, peptone and gelatin) and feather concentration (0.5g, 1g, 1.5g and 2g) were tested to find out the optimum conditions for the growth and keratin degradation of the chosen fungal strains. The temperature and feather concentration for the optimum growth of A. niger, A. terreus and A. flavus were 25 °C and 1.5g, 45 °C and 1g and 30 °C and 1.5g respectively. All three Aspergillus species exerted better growth at pH 9 and with bovine serum albumin as the substrate.

Micrococcus luteus: A Potential Keratinolytic Bacteria Isolated from Poultry Waste Dumping Site at Namakkal District, Tamil Nadu, India

: In this study, the experimental soil samples were collected from poultry waste dumping site at Namakkal district, Tamil Nadu, India. From the five soil samples, 15 bacterial colonies were isolated based on Keratinolytic activity with source of agar nutrient medium, nitrogen, carbon and feather meal powder. After the incubation period only 6 isolates showed clear zone of hydrolysis around colony in feather meal agar medium incubated at 37 C for 72 h. The Bacterial species were identified by the morphological and biochemical tests compared with Bergey’s manual of systematic bacteriology IV edition. The obtained bacterial genera from poultry waste dumping sites were Escherichia coli, Enterococcus faecalis, Micrococcus luteus, Klebsiella pneumoniae, Proteus sp., Staphylococcus aureus, Salmonella sp. and Pseudomonas aeruginosa. During the Keratinolytic activity the maximum zone of inhibition was noticed in the isolate No.3, and it was identified as Micrococcus luteus. The identified potential keratinolytic bacterial species culture was optimized with different temperature, pH, nitrogen and carbon sources for bulk production of enzyme. The bulk production of enzyme was precipitated with 20% of ammonium sulphate and it was purified with dialysis bag and subjected to assay procedure for determination of enzyme activity. The antibiotic sensitivity was tested on the isolated bacterial isolates and the highest antibiotic resistance was observed in Staphylococcus aureus (75%) and second most Salmonella (70%) and followed by Klebsiella pneumoniae (60%), Enterococcus faecalis (50%) and Escherichia coli (45%) .

Isolation and Identification of Feather Degrading Bacteria from Poultry Waste Dump site along Enugu-Port Harcourt Express way, Gariki, Awkunanaw, Enugu.

The investigation was aimed at isolating and characterizing the culturable feather degrading bacteria from soils of the poultry waste dump site along Enugu - Port Harcourt express way by Gariki, Awkunanaw, Enugu. The bacteria that were isolated were tested for their capability to grow on feather meal agar (FMA). The proteolytic bacteria were tested for feather degradation and were further identified according to their morphological and biochemical characteristics. The isolate were gram positive, rod shaped and spore-former and were able to utilize glucose, sucrose and lactose. They were also catalase and oxidase positive. They showed typical characteristics of Bacillus sp., thus were from the Bacillus genus. This Bacillus strain is therefore a promising strain for the management of chicken feather waste through biotechnological processes.

Keratinolytic protease from Pseudomonas aeruginosa for leather skin processing

BackgroundThe leather industry generates huge volume of waste each year. Keratin is the principal constituents of this waste that is resistant to degradation. Some bacteria have the ability to degrade keratin through synthesis of a protease called keratinase that can be used as sources of animal feed and industrial production of biodiesel, biofertilizer, and bioplastic. Majority of the studies focused on keratin degradation using gram-positive bacteria. Not much of studies are currently available on production of keratinase from gram-negative bacteria and selection of best parameters for the maximum production of enzyme. The aim of this study was to isolate and characterize both groups of bacteria from soil for keratinase and optimize the production parameters. ResultsA total of 50 isolates were used for initial screening of enzyme production in skim milk, casein, and feather meal agar. Out of 50, five isolates showed significantly higher enzyme production in preliminary screening assays. Morphological and biochemical characterization revealed 60% of the isolates as gram-negative bacteria including two highest enzyme-producing isolates. The isolates were identified as Pseudomonas aeruginosa through sequencing of 16S rRNA gene. Maximum production of enzyme from P. aeruginosa YK17 was achieved with 2% chicken feather, beef extract, and ammonium nitrate as organic and inorganic nitrogen sources and glucose as a carbon source. Further analysis revealed that 3% inoculum, 40 °C growth temperature and 72-h incubation, resulted in maximum production of keratinase. ConclusionThe overall results showed significant higher production of enzyme by the P. aeruginosa YK17 that can be used for the degradation of recalcitrant keratin waste and chemical dehairing in leather industries, thereby preventing environmental pollution.

Feather degradation efficiency and hide dehairing ability of a new keratinolytic bacillus halotolerans strain, isolated from a tannery wastewater

Here, we report a new keratinolytic-producing bacterium identified as Bacillus halotolerans 4BC based on 16S rRNA gene sequencing. 4BC strain isolated from a tannery wastewater, showed proteolytic activity when grown on keratin azure, bovine hair and feather meal agar plates. B. halotolerans 4BC degraded almost 88% of chicken feathers after 10 days of cultivation in feather powder broth at pH 8 and 37°C. It was also efficiently able to degrade bovine hair keratin, despite the complexity of this substrate in comparison to feather keratin. The effects of different liquid to substrate ratios, inoculum sizes and incubation times on keratinase production were studied using response surface methodology to find the optimum conditions required for maximum B. halotolerans keratinase yield. The maximum keratinase yield (1059±53 mU/ml) was found under the following conditions: incubation period of 10 days, liquid/solid ratio of 5 and inoculum size of 2.3 % v/v). The crude enzyme exhibited a remarkable activity and stability under high temperature and alkaline conditions (pH 10 at 80°C). Additionally, the touch-visual and histological results demonstrated that the enzyme treated dehaired hides exhibit similar or improved characteristics without damaging the collagen layer, which makes the crude keratinase a potential effective and eco-friendly candidate for application in leather industry to avoid pollution problems associated with the use of chemicals.

Characterization of snake scat flora for production of protease, keratinase and esterase enzymes

Snakes are reptiles found in diverse geographical conditions and are known to ingest their prey lacking the step of chewing. The indiginous microbiota of snake must be elevating its digestive efficiency through secretion of various enzymes which may prove significant for industrial applications as well. In present study, scat samples of 12 snakes were collected from Rajiv Gandhi Zoological Park, Katraj, Pune for isolation of snake scat flora. Samples were spread plated on nutrient agar, trypticase soya agar, yeast peptone dextrose agar, brain heart infusion agar, salmonella shigella agar and ravan agar. 371 morphologically distinct isolates were obtained and screened qualitatively for protease, keratinase and esterase using skim milk agar, feather meal agar and tributyrin agar respectively. Among the isolates, 46% were positive for protease, 22% were positive for keratinase and maximum isolates i.e. 85%, were positive for esterase. 20% of total isolates showed production of all three enzymes. The first five isolates showing largest zone of clearance in qualitative assays were characterized quantitatively for protease and keratinase. Results obtained indicate that snake scat flora is a large untapped reservoir of industrially important microbial enzymes and can be a potential resource for degradation of animal tissue waste generated from slaughter house and poultry industries.

Partial Characterization of Keratinolytic Activity of Local Novel Bacteria Isolated from Feather Waste

Three keratinolytic bacterial isolates were characterized partially for their keratinase activity. Bacterial isolates were grown in feather meal agar. Ammonium sulfate precipitation followed by dialysis was performed to know the bacterial isolate keratinase activity in differet pH and temperature. Identification of the bacteria was done by using their 16S rRNA gene sequences. The result showed that bacterial growth was coinciding with keratinase activity. Precipitation with ammonium sulfate showed that keratinae activity of isolate A4 was optimum at 20% of ammonium sulphate, while B4 and B6 were more active at 70%. Keratinase activity increased after dialysis. Keratinase of A4 showed to have optimum activity at temperature of 45oC and pH=8, B4 was optimum at temperature of 35oC and pH=7, while B6 was optimum at temperature of 40oC and pH=7, respectively. Identification of the bacterial isolates using 16S rRNA gen showed that A4, B4, and B6 were closed to Leclercia adecarboxylata strain M-X17B, Azotobacter chroococcum strain ABA-1, and Stenotrophomonas maltophilia strain BIW by 97%, 99%, and 98%, respectively. Two bacteria L. adecarboxylata and A. chroococcum were firstly reported to produce keratinase.

Prospecting soil bacteria from subtropical Brazil for hydrolases production

AbstractEighteen bacterial strains were isolated from soil of an urban area located in a transition zone between the Atlantic Forest and Pampa biomes, in southern Brazil. These strains were screened for cellulolytic, lipolytic and proteolytic potentials. Eleven isolates (61%) were able to produce cellulolytic enzymes on carboxymethylcellulose (CMC) agar plates, 14 isolates (78%) were proteolytic on skim milk agar plates, and all isolates demonstrated lipolytic/esterolytic potential on tributyrin agar (TBA) plates. From the 18 bacteria, nine (50%) were shown to produce the three investigated enzyme activities. Selected isolates were then evaluated for growth and enzyme production at different conditions of temperature and pH on CMC agar, TBA, and feather meal agar plates. As a general trend, growth and hydrolysis zones were observed at pH 6.0–9.0 and 30–37

Screening of Bacteria for Protease Production and Feather Degradation

Feathers are recalcitrant wastes produced by the poultry industry. Considering potential environmental hazards and the need for energy conservation/recycling, adequate approaches are demanded for feathers reclamation. Microbial conversion is an interesting alternative from both technological and economical perspectives. Therefore, 15 bacterial strains were isolated from a site containing waste feathers, and evaluated for proteolytic and keratinolytic potentials. From these bacterial isolates, seven produced extracellular proteases in milk agar plates, also demonstrating the ability to grow on feather meal agar plates, preferentially at pH values from 7 to 9, and at 30–37 °C. The isolate named CL33A displayed higher efficiency for feather degradation in qualitative assays, and selected for studies in feather broth (FB), a medium containing whole feathers (10 g/L) as the sole source of carbon, nitrogen and energy. CL33A degraded 29, 75, and 95 % of the feathers in FB, after 96, 144 and 216 h of growth, respectively. Feather degradation was corroborated by increases in soluble protein concentration and medium pH. Production of proteolytic enzymes reached maximal values after 216–240 h of growth on FB, and CL33A also produced proteases when cultivated in feather meal, peptone, and soy protein isolate. Through 16S rRNA gene sequencing, this feather-degrading isolate was identified as Bacillus sp. CL33A. Bioprocessing could be a suitable technology aiming the management and valorization of feathers/feather meal, due to the production of protein hydrolysates and also proteolytic enzymes that could be used as important biocatalysts.

Isolation and Screening of Keratinolytic Bacteria from Feather Dumping Soil in and Around Cuddalore and Villupuram, Tamil Nadu

The study was carried out to screen the keratinolytic bacteria isolated from poultry feather dumping soils collected from Cuddalore and Villupuram in Tamilnadu, India. Forty one isolates were screened from 15 different samples by their growth and feather degrading ability on feather meal agar, and they were named as FDS01 to FDS41. Proteolytic activity of the isolates was screened on casein agar and their efficiency ranged from 4 to 18 mm. Secondary screening of the isolates was determined by keratinase activity. The isolates such as FDS03, FDS05, FDS11, FDS15, FDS17, FDS27 and FDS37 showed maximum keratinase activity and completely decomposed feather in 21 days of incubation (37 °C). In addition, the keratin azure assay was performed with the supernatants in 72 h culture, the isolate FDS15 showed high keratinase specific activity (16.5 ± 2.5 U/ml). The efficient strain was further characterized by biochemical and physiological properties and it was confirmed as Bacillus subtilis by 16S rDNA sequencing.

Isolation and Selection of Feather-Degrading Aerobic Bacteria From Poultry Processing Plants in Mekong Delta of Vietnam

Studies on keratinolytic microorganism have been mainly related to biotechnological applications based on their capability for decomposition of keratin-containing wastes to produce animal feed and bio-fertilizer. However, these organisms have ecological relevance to recycling keratinous residues in nature. This study aimed to select and identify new local potential feather - degrading bacteria for applications in biotechnological processes in Mekong Delta. A total of 21 aerobic, rod-shaped isolates from Mekong Delta poultry processing plants showed capability to growth on feather meal agar medium. They all expressed clear zones around the colonies on milk agar medium indicating proteolytic activity. They also hydrolyzed 24.43% to 58.13% of chicken feather dry weight after 7 days incubation at 37 o C and partially disintegrated the whole feather after 10 days. The isolates K15 and K14 showed the most prominent feather-degrading activity were further identified according to their morphology and physiological characteristics. Molecular identification based on their 16S rDNA gene sequence also carried out and revealed that K14 as Chryseobacterium indologenes ; whereas K15 was highly related to Bacillus subtilis.

Feather-degrading bacteria from the plumage of Neotropical Spectacled Thrushes (Turdus nudigenis)

ABSTRACT We studied the diversity and abundance of keratinolytic bacteria hosted by the plumage of Spectacled Thrushes (Turdus nudigenis), and their capacities to break down feathers in vitro. From 40 individuals sampled in Venezuela during the rainy and dry seasons, we isolated 18 bacterial isolates able to grow on feather meal agar, a medium selective of bacteria capable of extracting energy and nitrogen from feather keratin. Fourteen of these isolates were not previously known to grow on feather keratin. Bacillus cereus was the most prevalent, isolated from 85% of all individuals. Percentage of birds colonized by keratinolytic bacteria, prevalence of the most common bacteria, average number of bacteria species harbored per bird, and average abundance per bird of the most prevalent bacteria were not dependent on season. Capacity to degrade feathers in liquid culture varied extensively among bacterial isolates; four of them were able to noticeably damage feathers, but only B. cereus totally disintegrated...

Study of the Production of Alkaline Keratinases in Submerged Cultures as an Alternative for Solid Waste Treatment Generated in Leather Technology

Six nonpathogenic fungal strains isolated from alkaline soils of Buenos Aires Province, Argentina (Acremonium murorum, Aspergillus sidowii, Cladosporium cladosporoides, Neurospora tetrasperma, Purpureocillium lilacinum (formerly Paecilomyces lilacinus), and Westerdikella dispersa) were tested for their ability to produce keratinolytic enzymes. Strains were grown on feather meal agar as well as in solid-state and submerged cultures, using a basal mineral medium and "hair waste" as sole sources of carbon and nitrogen. All the tested fungi grew on feather meal agar, but only three of them were capable of hydrolyzing keratin, producing clear zones. Among these strains, P. lilacinum produced the highest proteolytic and keratinolytic activities, both in solid-state and submerged fermentations. The medium composition and culture conditions for the keratinases production by P. lilacinum were optimized. Addition of glucose (5 g/l) and yeast extract (2.23 g/l) to the basal hair medium increased keratinases production. The optimum temperature and initial pH for the enzyme production were 28℃ and 6.0, respectively. A beneficial effect was observed when the original concentration of four metal ions, present in the basal mineral medium, was reduced up to 1:10. The maximum yield of the enzyme was 15.96 Uc/ml in the optimal hair medium; this value was about 6.5-fold higher than the yield in the basal hair medium. These results suggest that keratinases from P. lilacinum can be useful for biotechnological purposes such as biodegradation (or bioconversion) of hair waste, leading to a reduction of the environmental pollution caused by leather technology with the concomitant production of proteolytic enzymes and protein hydrolyzates.

Isolation and characterization of feather degrading bacteria from Mauritian soil

This study is aimed at isolating and characterizing new culturable feather degrading bacteria from soils of the University of Mauritius Farm. Bacteria that were isolated were tested for their capability to grow on feather meal agar (FMA). Proteolytic bacteria were tested for feather degradation and were further identified according to their morphological and biochemical characteristics. All of the three isolates were from the Bacillus genus. Maximum enzyme activity was obtained from isolate DF1a. Maximum keratinolytic activity of 128 U/ml and maximum proteolytic activity of 373 U/ml were obtained. The optimal conditions for the keratinolytic activity of this strain were determined to be pH 8.0 and temperature of 70°C. In addition, this isolate was able to completely degrade a whole chicken feather within a period of 14 days at room temperature (28±2°C). These three Bacillus strains (DF1a, DF2b and DF3) are therefore promising strains for the management of chicken feather waste through biotechnological processes.

Characterization of feather-degrading bacteria from Brazilian soils

Studies on keratinolytic microorganisms have been mainly related to their biotechnological applications and association with animal pathologies. However, these organisms have an ecological relevance to recycling keratinous residues in nature. This work aimed to select and identify new culturable feather-degrading bacteria isolated from soils of Brazilian Amazon forest and Atlantic forest. Bacteria that were isolated from temperate soils and bacteria from Amazonian basin soil were tested for their capability to grow on feather meal agar (FMA). Proteolytic bacteria were tested for feather degradation and were further identified according to their morphological and biochemical characteristics. Also, molecular identification based on 16S rDNA gene sequencing was carried out. A total of 24 proteolytic and 20 feather-degrading isolates were selected; Most of the isolates were from the Bacillus genus (division Firmicutes), but one Aeromonas, two Serratia (γ-Proteobacteria), and one Chryseobacterium (Cytophaga–Flavobacterium group).

Degradation of Chicken Feather a Poultry Waste Product by Keratinolytic Bacteria Isolated from Dumping Site at Ghazipur Poultry Processing Plant

Feathers are byproduct waste of poultry processing plant and produced in large amount. A small percentage of feather waste is steamed, chemically treated, ground, to form feather meal a dietary protein supplement for animals. Alternatively, keratin can be biodegraded by some Keratinolytic bacteria and in this study Keratinase producing bacteria and their Keratinolytic enzyme production was investigated. Soil sample was collected from Ghazipur poultry waste site, Ghaziabad, India, a feather dumping site. Soil sample were inoculated in three enrichment media and colonies producing clear zone in feather meal agar were selected and identified as B. megaterium SN1, B. thuringenesis SN2, B. Pumilis SN3 were able to degrade chicken and pigeon feathers. They produced extracellularly Keratinolytic enzymes in enrichment media with 10% Feather meal powder. We report that Keratinase and Protease activity were detected in the culture supernatant and optimal medium for extracellular production of Keratinase and Protease is feather meal media 2 at pH (7.5) and temperature (30oC). There was complete degradation of feathers in 120 h of incubation and 0-80% Ammonium sulphate fraction showed 1.5 fold purification for Keratinase and 1.3 fold purification for Protease over the crude enzyme preparation. The keratinous waste can be biologically degraded by enzymes or the microbe itself to form useful products.

Biochemical and Molecular Characterization of a New Local Keratinase Producing Pseudomomanas sp., MS21

This study aimed to isolate and identify a new local bacterial strain, able to completely degrade keratin-rich wastes into soluble and useful materials which can be used in many proposes. Bacterial keratinases are of particular interest because of their action on insoluble keratin substrates and generally on a broad range of protein substrates. These enzymes have been studied for de-hairing processes in the leather industry and hydrolysis of feather and keratin. Samples from poultry industry wastes, soil, water, fodder and feather were collected from different places in Jeddah, Saudi Arabia. Each sample was plated on feather meal agar plates containing 5 g L feather as the sole carbon and nitrogen source and 1 the obtained colonies were selected, purified and their growth were detected on skimmed milk agar and feather meal broth media. The well grown isolates on feather meal agar which producing the largest clearing zone on skimmed milk plate were selected for keratinase assays. Out of 23 bacterial isolates, 7 isolates were selected. The best keratinase producing bacterium kera MS21 was selected and identified based on morphological, physiological and some biochemical characteristics. It was recorded as a species belonging to the genus Pseudomonas and identified as Pseudomonas sp. The results of identificatio n were confirmed by 16S rDNA studies. Precipitation and purification of the keratinase enzyme in addition to factors affecting enzyme activity were studied. The enzyme molecular weight was determined to be of 30 KDa using sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis. The optimum temperature and pH were determined to be 37°C and pH 8.0, respectively. The effect of some proteases inhibitors and activators were also studied.

Keratinolytic potential of a novel Bacillus sp. P45 isolated from the Amazon basin fish Piaractus mesopotamicus

Bacillus sp. P45, isolated from the intestine of the Amazon basin fish Piaractus mesopotamicus, showed proteolytic activity when grown on skimmed milk and feather meal agar plates. The keratinolytic potential of this strain was evaluated on whole feather broth and human hair broth. Bacillus sp. P45 degraded almost 90% of chicken feathers after 72 h of submerged cultivation on whole feather broth, and the production of extracellular proteases was observed. The formation of thiol groups was also detected during growth, indicating the contribution of sulphitolysis to the efficient hydrolysis of feather keratin. Nevertheless, Bacillus sp. P45 was unable to degrade hair keratin, possibly due to the conformational diversity of this substrate in comparison to feather keratin. Additionally, preliminary results demonstrated that this strain might be utilized in the degradation of recalcitrant collagen-containing wastes. The keratinolytic character of Bacillus sp. P45 might be utilized in environmental-friendly processes such as bioconversion of waste feathers, representing an alternative way of waste management that could lead to the production of value-added products such as microbial biomass, protein hydrolysates and proteolytic enzymes.