Degradation Of Chicken Feathers Research Articles

Bacillus velezensis strain NA16 shows high poultry feather-degrading efficiency, protease and amino acid production

Isolated Bacillus velezensis strain NA16, which produces proteases, amino acids and the transcription levels of different keratinolytic enzymes and disulfide reductase genes in whole gene sequencing, was evaluated during feather degradation. The result shows under optimum fermentation conditions, chicken feather fermentation showed total amino acid concentration of 7599 mg/L, degradation efficiency of 99.3% at 72 h, and protease activity of 1058 U/mL and keratinase activity of 288 U/mL at 48 h. Goose feather fermentation showed total amino acid concentration of 4918 mg/L (96 h), and degradation efficiency was 98.9% at 120 h. Chicken feather fermentation broth at 72 h showed high levels of 17 amino acids, particularly phenylalanine (1050 ± 1.90 mg/L), valine (960 ± 1.04 mg/L), and glutamic (950 ± 3.00 mg/L). Scanning electron microscopy and Fourier transform infrared analysis revealed the essential role of peptide bond cleavage in structural changes and degradation of feathers. Protein purification and zymographic analyses revealed a key role in feather degradation of the 39-kDa protein encoded by gene1031, identified as an S8 family serine peptidase. Whole genome sequencing of NA16 revealed 26 metalloproteinase genes and 22 serine protease genes. Among the proteins, S8 family serine peptidase (gene1031, gene1428) and S9 family peptidase (gene3132) were shown by transcription analysis to play major roles in chicken feather degradation. These findings revealed the transcription levels of different families of keratinolytic enzymes in the degradation of feather keratin by microorganisms, and suggested potential applications of NA16 in feather waste management and amino acid production.

Bacillus thuringiensis VP4: A potential keratinase producer isolated from poultry waste soils of Himachal Pradesh

Keratinase enzymes are protein hydrolyzing enzymes belonging to the serine hydrolase group and act specifically on keratin proteins to degrade them. The current study was conducted to isolate best keratinase producer bacterial strains. Four Bacillus species (B. cereus PP1- OP748781, B. cereus JP1- OP748782, B. cereus TP1- OP748783 and B. thuringiensis VP4- OP420549), were isolated from the poultry farms of Himachal Pradesh. These strains were evaluated for keratinase production by using chicken feathers in shake flask culture. Among four isolates, Bacillus thuringiensis VP4 showed highest enzymatic activity 343 U/ml. The molecular weight of the keratinase was observed 45 KDa by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis. The optimization of enzyme production was done with isolate Bacillus thuringiensis VP4 at various parameters such as temperature, pH and effect of metal ions. The maximum keratinase production was observed at 35°C temperature and pH 10.0. The isolated strain Bacillus thuringiensis VP4 might be used to produce poultry compost through degradation of chicken feathers and poultry waste in short time which may also be helpful for farmers and overcoming environmental pollution.

The degradation of chicken feathers by Ochrobactrum intermedium results in antioxidant and metal chelating hydrolysates and proteolytic enzymes for staphylococcal biofilm dispersion.

The increase in the generation of chicken feathers, due to the large production of the poultry industry, has created the need to search for ecologically safer ways to manage these residues. As a sustainable alternative for recycling keratin waste, we investigated the ability of the bacterium Ochrobactrum intermedium to hydrolyze chicken feathers and the valorization of the resulting enzymes and protein hydrolysate. In submerged fermentation with three different inoculum sizes (2.5, 5.0, and 10.0mg of bacterial cells per 50mL of medium), the fastest degradation of feathers was achieved with 5.0mg cells, in which a complete decomposition of the substrate (96h) and earlier peaks of keratinolytic and caseinolytic activities were detected. In the resulting protein hydrolysate, we noticed antioxidant and Fe2+ and Cu2+ chelating activities. ABTS scavenging, Fe3+-reducing ability and metal chelating activities of the fermentative samples followed the same trend of feather degradation; as feather mass decreased in the media, these activities increased. Furthermore, we noticed about 47% and 60% dispersion of established 7-day biofilms formed by S. aureus after enzymatic treatment for 5h and 24h, respectively. These findings highlight the potential use of this bacterium as an environmentally friendly alternative to treat this poultry waste and offer valuable products.

Effect of ultrasound on keratin valorization from chicken feather waste: Process optimization and keratin characterization

Chicken feather (CF) has been deemed as one of the main poultry byproducts with a large amount produced globally. However, the robust chemical nature of chicken feathers has been limiting in its wide-scale utilization and valorization. The study proposed a strategy of keratin regeneration from chicken feather combining ultrasound and Cysteine (Cys)-reduction for keratin regeneration. First, the ultrasonic effect on feather degradation and keratin properties was systematically explored based on Cys-reduction. Results showed that the feather dissolution was significantly improved by increasing both ultrasonic time and power, and the former had a greater impact on keratin yield. However, the treatment time over 4h led to a decrease of keratin yield, producing more soluble peptides, > 9.7% of which were<0.5kDa. Meanwhile, prolonging time decreased the thermal stability with weight loss at a lower temperature and amino acids content (e.g., Ser, Pro and Gly) of keratin. Conversely, no remarkable damage in chemical structure and thermal stability of regenerated keratin was observed by only increasing ultrasonic power, while the keratin solubility was notably promoted and reached 745.72mg·g-1 in NaOH (0.1M) solution (400W, 4h). The regenerated keratin under optimal conditions (130W, 2.7h, and 15% of Cys) possessed better solubility while without obvious damage in chemical structure, thermal stability, and amino acids composition. The study illustrated that ultrasound physically improved CF degradation and keratin solubility without nature damage and provided an alternative for keratin regeneration involving no toxic reagent, probably holding promise in the utilization and valorization of feather waste.

Keratinases from Streptomyces netropsis and Bacillus subtilis and Their Potential Use in the Chicken Feather Degrading

Feathers are the most prevalent agricultural waste generated by chicken farms, polluting the environment and wasting protein resources as a result of the accumulation of large amounts of feathers. Therefore, keratinase-producing microorganisms represent a promising potential technique for the degradation of feather waste. Streptomyces netropsis A-ICA and Bacillus subtilis ALICA, previously isolated from the rhizosphere of desert plants (Larrea tridentata and Prosopis juliflora) respectively, were assessed for their feather-degradation ability. Keratinase activity was optimized using various parameters, including incubation time, pH, temperature, and feather concentration. The maximum keratinase activity of S. netropsis A-ICA and B. subtilis ALICA (113.6 ± 5.1 and 135.6 ± 4.1 U/mL) was obtained at the 5th and 3rd day of incubation with initial pH of 7.0 and 7.5 at 25 and 30 °C, and 1% (w/v) of chicken feather, respectively. Under the optimized conditions, the concentration of soluble protein in the feather hydrolysate reached 423.3 ± 25 and 565.3 ± 7.7 µg/mL, with feathers weight loss of 84 ± 2 and 86± 1.5% by S. netropsis A-ICA and B. subtilis ALICA, respectively. The highest disulphide bond reductase activity reached 10.7 ± 0.4 and 10.96 ± 1.1 U/mL, after five and three days of inoculation with S. netropsis A-ICA and B. subtilis ALICA, respectively. Furthermore, the antioxidant activity of feather protein hydrolysate obtained by S. netropsis A-ICA and B. subtilis ALICA was evaluated using DPPH radical-scavenging activity, which exhibited a significant antioxidant potential with an IC50 value of 0.8 and 0.6 mg/mL. The 3D models of detected keratinases in both strains showed high similarity with subtilisin family. Further, the docking results clarified the importance of GSG and VVVFTP domains in B. subtilis and beta-keratin, respectively. The present study revealed the keratinolytic potential of S. netropsis A-ICA and B. subtilis ALICA in chicken feather degradation, which have potential application value and may be exploited as supplementary protein and antioxidant in animal feed formulations.

Parametrically optimized feather degradation by Bacillus velezensis NCIM 5802 and delineation of keratin hydrolysis by multi-scale analysis for poultry waste management

Enormous amounts of keratinaceous waste make a significant and unexploited protein reserve that can be utilized through bioconversion into high-value products using microbial keratinases. This study was intended to assess the keratinase production from a newly isolated B. velezensis NCIM 5802 that can proficiently hydrolyze chicken feathers. Incubation parameters used to produce keratinase enzyme were optimized through the Response Surface Methodology (RSM) with chicken feathers as substrate. Optimization elevated the keratinase production and feather degradation by 4.92-folds (109.7 U/mL) and 2.5 folds (95.8%), respectively. Time-course profile revealed a direct correlation among bacterial growth, feather degradation, keratinase production and amino acid generation. Biochemical properties of the keratinase were evaluated, where it showed optimal activity at 60 °C and pH 10.0. The keratinase was inhibited by EDTA and PMSF, indicating it to be a serine–metalloprotease. Zymography revealed the presence of four distinct keratinases (Mr ~ 100, 62.5, 36.5 and 25 kDa) indicating its multiple forms. NMR and mass spectroscopic studies confirmed the presence of 18 free amino acids in the feather hydrolysates. Changes in feather keratin brought about by the keratinase action were studied by X-ray diffraction (XRD) and spectroscopic (FTIR, Raman) analyses, which showed a decrease in the total crystallinity index (TCI) (1.00–0.63) and confirmed the degradation of its crystalline domain. Scanning electron microscopy (SEM) revealed the sequential structural changes occurring in the feather keratin during degradation. Present study explored the use of keratinolytic potential of the newly isolated B. velezensis NCIM 5802 in chicken feather degradation and also, unraveled the underlying keratin hydrolysis mechanism through various analyses.

Production of keratinous waste degrading enzyme by Arthroderma multifidum isolated from soil of Rajasthan, India

The aim of this study was to detect and evaluate the extracellular keratinase enzyme production by Arthroderma multifidum TKKASa (KU560574), a keratin-degrading fungus isolated from the keratin contaminated soil of Rajasthan, India. This study focused on the evaluation of the effect of keratin substrates, pH, incubation days, temperature and metal ions for keratinase enzyme production. The highest enzyme production by A. multifidum was observed on chicken feathers (56.25±0.69 U/mL) followed by human hair, animal hair and human nail clippings. The maximum keratinase production by A. multifidum was achieved at 40˚C with 58.80±0.98 U/mL enzyme activity and pH 8.0 (56.65±0.85 U/mL) after 12 days of fermentation. The addition of metal ions in basal salt media resulted in the decrease in enzyme production. This study reports keratinase production by A. multifidum and the high efficiency on the chicken feather degradation in comparison to human nail clipping, animal hair and human hair degradation. Its potential use is in biotechnological processes such as biodegradation of keratin wastes, eco-friendly dehairing and poultry feed production.

A sustainable approach for processing organic waste in India

There are about 3430 million poultry populations in India, with a waste generation of 3.30 million tons per year. India is the world's third-largest egg producer and the fourth-largest broiler chicken producer, and Tamil Nadu plays a significant role in poultry egg and meat production. As the poultry hub of Tamil Nadu, Namakkal has been struggling to manage these wastes dumped in open areas by the poultry farms and small industrial units in recent years. The dumping of Bio-organic waste like chicken feathers and chicken intestines in the municipal solid waste landfill creates an unpleasant odor, environmental contamination, and various health issues. These organic wastes can be recycled through composting as a sustainable approach to waste management. In this study, discarded chicken waste from the poultry units and slaughterhouses in and around the Namakkal was collected and mixed with other organic manure like cow dung, rice husk, and tea powder in various proportions to generate organic compost. The composting process has been carried out in-vessel composters for 40 days by both aerobic and anaerobic methods at the lab scale. The parameters such as C: N ratio, pH, Organic matter, Dry matter, Moisture content, and NPKvalues are analyzed for aerobic and anaerobic processes. It is found that the C: N ratio is optimum in aerobic compost compared to anaerobic compost. Also, it is observed that the aerobic compost had a positive influence on the plant growth, i.e., okra (ladies finger) seedlings, then the anaerobic compost. The study indicates that the addition of external agents is required for the complete and rapid degradation of chicken feathers due to fiber-rich keratin. Thus, the present study will effectively reduce the potential hazards of chicken waste disposal through the proposed sustainable approach.

Chryseobacterium aquifrigidense keratinase liberated essential and nonessential amino acids from chicken feather degradation

ABSTRACT Keratinous biomass valorization for value-added products presents a high prospect in ecological management and the advancement of the bio-economy. Consequently, soil samples from the poultry dumpsite were collected. The bacteria isolated on the basal salt medium were screened for keratinolytic activity. The potent chicken feathers degrading bacteria were identified through 16S rRNA gene sequencing and phylogenetic analysis. Fermentation process conditions were optimized, and the amino acid compositions of the feather hydrolysate were likewise quantified. Ten (10) proteolytic bacteria evaluated on skimmed milk agar showed intact chicken feather degradation ranging from 33% (WDS-03) to 88% (FPS-09). The extracellular keratinase activity ranged from 224.52 ± 42.46 U/mL (WDS-03) to 834.55 ± 66.86 U/mL (FPS-07). Based on 16S rRNA gene sequencing and phylogenetic analysis, the most potent keratinolytic isolates coded as FPS-07, FPS-09, FPS-01, and WDS-06 were identified as Chryseobacterium aquifrigidense FANN1, Chryseobacterium aquifrigidense FANN2, Stenotrophomonas maltophilia ANNb, and Bacillus sp. ANNa, respectively. C aquifrigidense FANN2 maximally produced keratinase (1460.90 ± 26.99 U/mL) at 72 h of incubation under optimal process conditions of pH (6), inoculum side (5%; v/v), temperature (30°C), and chicken feather (25 g/L). The feather hydrolysate showed a protein value of 67.54%, with a relative abundance of arginine (2.84%), serine (3.14%), aspartic acid (3.33%), glutamic acid (3.73%), and glycine (2.81%). C. aquifrigidense FANN2 yielded high keratinase titre and dismembered chicken feathers into amino acids-rich hydrolysate, highlighting its significance in the beneficiation of recalcitrant keratinous wastes into dietary proteins as potential livestock feed supplements.

Microbial bioconversion of feathers into antioxidant peptides and pigments and their liposome encapsulation.

The co-encapsulation of bioactive peptides obtained from degradation of chicken feathers and flexirubin-type pigment produced by Chryseobacterium sp. kr6 into phosphatidylcholine liposomes was investigated. Control empty liposomes showed mean diameter of 168.5 nm, varying to 185.4, 102.0 and 98.5 nm after the encapsulation of peptides, pigment and their co-encapsulation, respectively. Control liposomes presented zeta potential of - 20.9 mV, while the formulations containing the bioactive compounds showed values of - 30 mV or higher in magnitude. Infrared analysis revealed typical spectra for phosphatidylcholine, suggesting that no new chemical bonds were formed after encapsulation. ABTS radical scavenging assay showed that the antioxidant activity of the compounds was maintained after encapsulation. Feather waste can be a valuable substrate for simultaneous production of antioxidant peptides and pigment by Chryseobacterium sp. kr6, and their encapsulation into liposomes may be a suitable alternative for delivery of these natural antioxidants.

Proteolytic bacteria isolated from agro-waste dumpsites produced keratinolytic enzymes

Microbial bioconversion of carbonoclastic materials is an efficient tool for the exploitation and valorization of underutilized agro-industrial wastes. The agro-industrial sector accumulates tones of keratinous wastes biomass which may be valorized into high value products. Consequently, the keratinolytic potentials of some bacteria isolated from terrestrial milieu was evaluated. Soil samples were collected from dumpsites, keratinase producing bacteria were isolated. Bacterial species were identified through 16S rRNA gene sequences. The keratinase activity was assessed in relation to thiol formation, percentage feather degradation and quantitation of keratinase produced. Keratinolytic bacteria were identified as Bacillus spp. (accession numbers: MG214989 – MG214992, MG214997, MG214998, MG215000, MG215002–MG215005) and Arthrobacter sp. (accession numbers; MG215001). The degree of chicken feather degradation ranged from 61.5 ± 0.71 % to 85.0 ± 1.41 %. Similarly, the activity of keratinase, total protein and thiol group ranged from 198.18 ± 15.43–731.83 ± 14.14 U/mL; 0.09 ± 0.01–0.87 ± 0.05 mg/mL; and 0.69 ± 0.12–2.89 ± 0.11 mM respectively. Notably, Bacillus sp. Nnolim-K1 displayed the best keratinolytic potential with extracellular keratinase activity and feather degradation of 731.83 ± 14.14 U/mL and 85.0 ± 1.41 % respectively, and that is an indication of a potential relevance biotechnologically.

Degradation of chicken feathers by Aphanoascus keratinophilus and Chrysosporium tropicum strains from pellets of predatory birds and its practical aspect

The present study is the first report on the biodegradation of native keratin by fungi isolated from food pellets of birds of prey. The aim of the study was to evaluate the diversity of keratinolytic activity of 2 fungal species, Aphanoascus keratinophilus and Chrysosporium tropicum, isolated from pellets of raptors and to find a relationship between the origin of fungal strains and their keratinolytic activity. The feather weight loss ranged from 60% to 75% for A. keratinophilus and from 55% to 70% for Ch. tropicum. Strains isolated from kestrel and buzzard pellets transformed feathers after 6 weeks into a soluble protein form in the range from 11% to 17% and 12%–17%, respectively. A. keratinophilus strains transformed feather N into N–NH4+ maximally in 53% and minimally in 20%, whereas Ch. tropicum strains converted from approx. 3%–42%. Feather S was transferred to the medium as S–SO42- after 42 days in 74% by A. keratinophilus and from 2% to 68% by Ch. tropicum strains. The effectiveness of fungal strains isolated from buzzard and kestrel pellets, was generally higher than that of strains isolated from owl pellets. The passage of the tested fungal strains through the gastric barrier and their thermo-tolerance allow a conclusion that pellet-derived keratinolytic fungi (especially from diurnal raptors) are a suitable inoculum material for keratin waste composting.

Bacillus sp. FPF-1 Produced Keratinase with High Potential for Chicken Feather Degradation.

Chicken feathers are predominantly composed of keratin; hence, valorizing the wastes becomes an imperative. In view of this, we isolated keratinase-producing bacteria and identified them through the 16S rDNA sequence. The process condition for keratinase activity was optimized, and electron micrography of the degradation timelines was determined. Keratinolytic bacteria were isolated and identified as Bacillus sp. FPF-1, Chryseobacterium sp. FPF-8, Brevibacillus sp. Nnolim-K2, Brevibacillus sp. FPF-12 and Brevibacillus sp. FSS-1; and their respective nucleotide sequences were deposited in GenBank, with the accession numbers MG214993, MG214994, MG214995, MG214996 and MG214999. The degree of feather degradation and keratinase concentration among the isolates ranged from 62.5 ± 2.12 to 86.0 ± 1.41(%) and 214.55 ± 5.14 to 440.01 ± 20.57 (U/mL), respectively. In the same vein, 0.1% (w/v) xylose, 0.5% (w/v) chicken feather, an initial fermentation pH of 5.0, fermentation temperature of 25 °C and an agitation speed of 150 rpm, respectively, served as the optimal physicochemical conditions for keratinase activity by Bacillus sp. FPF-1. The time course showed that Bacillus sp. FPF-1 yielded a keratinase concentration of 1698.18 ± 53.99(U/mL) at 120 h. The electron microscopic imaging showed completely structural dismemberment of intact chicken feather. Bacillus sp. FPF-1 holds great potential in the valorization of recalcitrant keratinous biomass from the agro sector into useful products.

Synthesis of Keratin Nanoparticle and Characterization using FTIR

Chicken feathers consists of more amount of proteins in it. Each year in poultry farms the chicken feathers are wasted and dumped into the environment, because degradation of chicken feathers is more complicated to do, even though some ways like burying and burning are available to degrade the chicken feather it is not environmental friendly and because of this the environment gets polluted. Keratin is a group of fibrous protein and has many useful applications. Considering this advantage, the wasted chicken feathers are collected and the keratin is extracted using sodium sulfite as the solvent. The keratin extraction is confirmed by biuret test. The characterization studies are done using FTIR analysis. Further the keratin nanoparticles are synthesized using Silver Nitrate.

Feather degrading, phytostimulating, and biocontrol potential of native actinobacteria from North Eastern Indian Himalayan Region.

Twelve actinobacterial strains were isolated from tomato rhizospheric soil from Manipur, a state in North East Indian Himalayan Region and screened for keratinolytic and plant growth promoting traits. Nine promising isolates were identified as Streptomyces species using partial 16S rRNA gene sequencing. Among the seven isolates showing chicken feather degradation activity, three keratinolytic strains RCM-SSR-2, -6, and -12 were found to be the most efficient feather degrading strains achieving 90% feather weight loss within 48 h of incubation. They also showed maximum keratinase and soluble peptide production. Strain RCM-SSR-2, -5, -6, -8, and -11 showed positive results for all plant growth promoting traits tested. Maximum indole-3-acetic acid production was exhibited by RCM-SSR-6. Strain RCM-SSR-1, -2, -5, -6, -9, and -11 showed antagonistic activity against three important plant pathogens. Feather hydrolysate of RCM-SSR-6 was also evaluated for in vitro seed germination test using garden pea seeds. Higher concentration of feather protein hydrolysate (3 mg ml-1 ) inhibited shoot and root length of the germinating embryo. However, lower concentration (0.01 mg ml-1 ) of feather protein hydrolysate promoted seed germination. Among the 12 strains, four isolates namely RCM-SSR-1, -2, -5, and -6 were found to be promising as multi-traits plant growth promoting rhizobacteria for development of organic fertilizer, phytostimulator, and biocontrol agents.

Feather degradation potential of Stenotrophomonas maltophilia KB13 and feather protein hydrolysate (FPH) mediated reduction of hexavalent chromium.

An efficient keratinolytic strain of Stenorophomonas maltophilia KB13 was isolated from feather disposal site of Bilaspur, Chhattisgarh, India. The strain could metabolize 10 g/l chicken feathers as sole source of carbon and nitrogen. Soluble protein, amino acid, and cysteine content were found to be maximum (690.6 ± 8.7, 688.9 ± 9.12 and 21 ± 0.36 µg/ml, respectively) at late logarithmic phase of growth. Protease and keratinase activity reached its maximum level (103.26 ± 7.09 and 178.5 ± 9.10 U/ml) at the 4th day of incubation. The feather protein hydrolysate (FPH) obtained after degradation of chicken feathers was utilized to reduce hexavalent chromium. About 78.4 ± 2.4 and 63.6 ± 2.2 % reduction of 50 and 100 mg/l Cr(VI), respectively, was observed after 60 min of incubation with FPH. Further, there was no effect of autoclaved FPH on Cr(VI) reduction indicating that any bacterial enzyme was not involved in reduction process. Cr(VI) reduction was significantly inhibited by 10 mm Hg2+ ions indicating the role of sulfur-containing amino acids in reduction process. FTIR analysis confirmed that chromium reduction occurred due to oxidation of amino acids cysteine and cystine. This study shows that FPH arising after feather degradation can be employed as a potential candidate for the reduction of hexavalant chromium.

Purification and Characterization of a Membrane-Unbound Highly Thermostable Metalloprotease from Aeromonas Caviae

The main objective of the current study was to purify and characterize an alkaline thermostable metalloprotease from Aeromonas caviae. The enzyme was subjected to a two-step purification scheme using ammonium sulfate [(NH4)2SO4] fractionation and ion-exchange chromatography on a DEAE-sepharose fast flow column. The fraction which precipitated with 40–60 % (w/v) of [(NH4)2SO4] exhibited the highest enzyme activity. Anion-exchange chromatography resulted in approximately 51-fold purification, with a yield of 64.7 %. The enzyme was successfully purified to homogeneity, and this was confirmed on sodium dodecyl sulfate-polyacrylamide gel (SDS-PAGE). A single band with an approximate molecular mass of ∼42 kDa was observed. The maximum enzymatic activity was observed at pH 8 with azocasein as the substrate, and the enzyme was stable in the pH range of 6–10 after 5 h of incubation. The purified enzyme was active in the temperature range between 50 and 60 °C and showed 80 % loss in enzymatic activity upon heating at 70 °C. The K m and V max values for the purified protease, with azocasein as substrate under optimal reaction conditions (pH 8 and 50 °C) were 0.74 and 122.4 mg/ml, respectively. The protease was investigated for its application for the degradation of chicken feathers. The high enzymatic activity, pH, and thermal stability of AU04 protease make it an industrially important enzyme.

Isolation and Characterization of Protease from Bacillus spp and Serratia spp

Proteases are the largest group of enzymes that have a wide variety of industrialapplications in detergent, leather industry, pharmaceutical industry and bioremediation processes. In the current study, processed water from Pallavaramleather industry (Chennai &amp; Tamilnadu) was used for isolation of organisms producing protease. Bacillus spp and Serratia spp were isolated on 0.5% casein minimal media. The presence of protease was confirmed by paper chromatography and estimated by ninhydrin method. The protease activity of Bacillus species was high at the temperature of 60oC, pH 9 and the concentration was found to be 280mg/100ml, whereas the activity of protease for Serratia species was high at the temperature of 40oC, pH 5 and at concentration of 240mg/100ml. The highest concentration at which the activity of protease was maximum was 2 % for both the organisms. The protease enzyme used for the blood stain removal and degradation of outer gelatin layer of X‐ray films was good however chicken feather degradation was less.

Keratinases and sulfide from Bacillus subtilis SLC to recycle feather waste

The aim of this study is to investigate the culture conditions of chicken feather degradation and keratinolytic enzyme production by the recently isolated Bacillus subtilis SLC and to evaluate the potential of the SLC strain to recycle feather waste discarded by the poultry industry. The SLC strain was isolated from the agroindustrial waste of a poultry farm in Brazil and was confirmed to belong to Bacillus subtilis by rDNA gene analysis. There was high keratinase production when the medium was at pH 8 (280 U ml(-1)). Activity was higher using the inoculum propagated for 72 h on 1% whole feathers supplemented with 0.1% yeast extract. In the enzymatic extract, the keratinases were active in the pH range from 2.0 to 12.0 with a maximum activity at pH 10.0 and temperature 60°C. For gelatinase the best pH was 5.0 and the best temperature was 37°C. All keratinases are serine peptidases. The crude enzymatic extract degraded keratin, gelatin, casein, and hemoglobin. Scanning electron microscopy showed Bacillus cells adhered onto feather surfaces after 98 h of culture and degraded feather filaments were observed. MALDI-TOF mass spectrometric analysis showed multiple peaks from 522 to 892 m/z indicating feather degradation. The presence of sulfide was detected on extracellular medium probably participating in the breakdown of sulfide bridges of the feather keratin. External addition of sulfide increased feather degradation.

Alkaline proteases produced by Bacillus licheniformis RP1 grown on shrimp wastes: Application in chitin extraction, chicken feather-degradation and as a dehairing agent

The current increase in the amount of shrimp wastes produced by the shrimp industry has led to the need in finding new methods for shrimp wastes disposal. In this study, Bacillus licheniformis RP1 was shown to produce proteases when grown in media containing shrimp wastes powder as a sole carbon and nitrogen source, indicating that this bacteria could obtain its carbon and nitrogen requirements directly from shrimp wastes. The maximum protease production was obtained when the strain was grown in a medium containing (g/L): shrimp wastes powder 30, KCl 1.5, K2HPO4 0.5, and KH2PO4 0.5. Using casein zymography, the crude protease preparation was found to produce at least seven proteases. The proteases of B. licheniformis RP1 were tested for shrimp waste deproteinization in the preparation of chitin. The percent of protein removal after 3 h hydrolysis at 60°C and at an enzyme/substrate (E/S) ratio of 0.5 and 5 (Unit of enzyme/mg of protein) were about 68 and 81%, respectively. Additionally, B. licheniformis RP1 showed important feather degrading activity. Complete solubilisation of whole feathers was observed after 24 h of incubation at 50°C. More interestingly, the RP1 proteolytic preparation demonstrated powerful dehairing capabilities for hair removal from skin. Collagen, which is the major leather-forming protein, was not significantly degraded. Considering its promising properties, B. licheniformis RP1 enzymatic preparation may be considered a potential candidate for future use in several biotechnological processes.