Anaerobic digestion is a sustainable and economically feasible waste management technology, which lowers the emission of greenhouse gases (GHGs), decreases the soil and water pollution, and reduces the dependence on fossil fuels. The present thesis investigates the anaerobic digestion of waste from food-processing industries, including citrus wastes (CWs) from juice processing and chicken feather from poultry slaughterhouses. Juice processing industries generate 15–25 million tons of citrus wastes every year. Utilization of CWs is not yet resolved, since drying or incineration processes are costly, due to the high moisture content; and biological processes are hindered by its peel oil content, primarily the D-limonene. Anaerobic digestion of untreated CWs consequently results in process failure because of the inhibiting effect of the produced and accumulated VFAs. The current thesis involves the development of a steam explosion pretreatment step. The methane yield increased by 426 % to 0.537 Nm3/kg VS by employing the steam explosion treatment at 150 °C for 20 min, which opened up the compact structure of the CWs and removed 94 % of the D-limonene. The developed process enables a production of 104 m3 methane and 8.4 L limonene from one ton of fresh CWs. Poultry slaughterhouses generate a significant amount of feather every year. Feathers are basically composed of keratin, an extremely strong and resistible structural protein. Methane yield from feather is low, around 0.18 Nm3/kg VS, which corresponds to only one third of the theoretical yield. In the present study, chemical, enzymatic and biological pretreatment methods were investigated to improve the biogas yield of feather waste. Chemical pretreatment with Ca(OH)2 under relatively mild conditions (0.1 g Ca(OH)2/g TSfeather, 100 °C, 30 min) improved the methane yield to 0.40 Nm3/kg VS, corresponding to 80 % of the theoretical yield. However, prior to digestion, the calcium needs to be removed. Enzymatic pretreatment with an alkaline endopeptidase, Savinase®, also increased the methane yield up to 0.40 Nm3/kg VS. Direct enzyme addition to the digester was tested and proved successful, making this process economically more feasible, since no additional pretreatment step is needed. For biological pretreatment, a recombinant Bacillus megaterium strain holding a high keratinase activity was developed. The new strain was able to degrade the feather keratin which resulted in an increase in the methane yield by 122 % during the following anaerobic digestion. / <p>Akademisk avhandling som för avläggande av teknologie doktorsexamen vid Chalmers tekniska högskola försvaras vid offentlig disputation den 1 juni 2012, klockan 10.00 i KA-salen, Kemigården 4, Göteborg.</p>

A indústria da avicultura mundial produz, anualmente, bilhões de toneladas de penas e penugens de frango, pato, peru e ganso. Grande parte desse produto de descarte é incinerado em aterros causando poluição da atmosfera e do solo. Por isso, foi crucial o desenvolvimento de novas ideias para aplicações comerciais do bioproduto de penas e penugens. Assim, neste trabalho de tese, caracterizaram-se as fibras de penas e penugens nos âmbitos físico-mecânico, térmico e acústico e desenvolveram-se dois produtos comerciais: nãotecidos de penas e de penugens pelo processo de agulhadeira e nãotecidos de nanofibras da queratina de penas e penugens por electrospinning. Os resultados foram analisados através de métodos estatísticos a fim de validar as análises. Pode-se, então reciclar as penas e utilizá-las como matéria-prima para a indústria têxtil e de materiais. Além disso, as penas são facilmente utilisáveis devido à sua qualidade, baixo custo e quantidade disponível. Deste modo, penas recicladas não só reduzem os custos do produto final, mas também criam um movimento ambiental para desenvolver uma economia circular eco-friendly. / The poultry industry produces billions tons of chicken, duck, turkey and goose feathers and down feathers worldwide annually. Most of these waste products are incinerated in landfills resulting in pollution of atmosphere and land. For these reasons, it was crucial to develop new ideas for commercial applications of feathers and downs as a fiber byproducts. In this thesis work, feathers and down as fibers were characterized in physical, mechanical, thermal and acoustic scopes and two commercial products were developed using feather and down feathers: nonwoven by dry laid needle punched process and nanofibers nonwovens of keratin by electrospinning process. The results were analyzed using statistical methods to validate the analysis. Thereby, feathers were recycled and used as a raw material for the textile and materials industry. Furthermore, they are easly usable due to their quality, low cost and the available quantity. Moreover, recycled feathers not only reduce the costs of the final product but also create an environmental movement to develop an eco-friendly circular economy.

Annuellement, l'industrie mondiale de la volaille produit des milliards de tonnes de plumes et de duvets de poule, canard, oie et dinde. Une grande partie de ces déchets sont incinérés dans des décharges polluant l'atmosphère et le sol. Il est donc crucial de développer de nouvelles idées pour des applications commerciales des bioproduits de plumes et de duvets. Ainsi, dans ce travail de thèse, les fibres de plumes et de duvets ont été caracterisées au niveau physique, mécanique, thermique et acoustique. Deux produits commerciaux ont été développés avec les plumes et les duvets : des nontissés par un processus d’aiguilletage et des nontissés de nanofibres de kératine par electrospinning. Les données ont été analysés en utilisant des méthodes statistiques pour valider les résultats. Les plumes ont pu être recyclées comme matière première pour l'industrie du textile et des matériaux. Les plumes sont facilement utilisables en raison de leur qualité, leur faible coût et les quantités disponibles. Ainsi, des plumes recyclées non seulement réduisent les coûts du produit final, mais aussi créent un mouvement écologique pour développer une économie durable. / The poultry industry produces billions tons of chicken, duck, turkey and goose feathers and down feathers worldwide annually. Most of these waste products are incinerated in landfills resulting in pollution of atmosphere and land. For these reasons, it was crucial to develop new ideas for commercial applications of feathers and downs as a fiber byproducts. In this thesis work, feathers and down as fibers were characterized in physical, mechanical, thermal and acoustic scopes and two commercial products were developed using feather and down feathers: nonwoven by dry laid needle punched process and nanofibers nonwovens of keratin by electrospinning process. The results were analyzed using statistical methods to validate the analysis. Thereby, feathers were recycled and used as a raw material for the textile and materials industry. Furthermore, they are easly usable due to their quality, low cost and the available quantity. Moreover, recycled feathers not only reduce the costs of the final product but also create an environmental movement to develop an eco-friendly circular economy.

Ziel dieser Arbeit war eine Untersuchung zur Häufigkeit des Wechsels von Legehennen zwischen Innen- und Außenbereichen, einschließlich der Aufenthaltsdauer außerhalb des Stalles, in Relation zum Federpicken und der Beschaffenheit des Integumentes. Der Einfluss der Haltungsbedingungen und der Einfluss des Genotyps wurden untersucht. Die Gruppe, die ohne Grünauslauf war, bewegte sich signifikant häufiger zwischen dem Stall und dem Wintergarten als andere Gruppen mit Grünauslauf. Die Aufenthaltsdauer im Stall und Wintergarten war in der Gruppe ohne Grünauslauf signifikant höher als bei anderen mit Grünauslauf (GA). Hennen, denen eine große Auslauffläche angeboten wurde (10m²/T) bewegten sich signifikant häufiger zu den Außenbereichen als andere mit einem Angebot von 2,5 m²/Tier. Hennen mit einem Angebot von 2,5 m²/Tier hielten sich länger auf dem Grünland auf als Hennen mit einer Besatzdichte von 10m²/T. Die höchsten Federpickaktivitäten waren in der Gruppe ohne GA im Vergleich zu den Gruppen mit GA. Im Vergleich zu anderen Gruppen mit GA, hatte die Gruppe ohne GA einen schlechteren Gefiederzustand. LSL Hennen bewegten sich im Vergleich zu den LT Hennen häufiger zwischen Innen- und Außenbereichen. LSL Hennen hielten sich im Vergleich zu den LT Hennen länger im Wintergarten auf. Dennoch hielten sich die LT Hennen im Vergleich länger auf dem Grünland auf. Die schlechteste Gefiederbeschaffenheit wiesen LSL Hennen im Vergleich zu LT Hennen auf. Die Resultate der vorliegenden Untersuchungen weisen darauf hin, dass die Auslaufnutzung einen positiven Einfluss auf den Gefieder- und Hautzustand hat. Die untersuchten Genotypen unterschieden sich in der Häufigkeit des Ortswechsels und der Aufenthaltsdauer im Grünauslauf. / The aim of this work was to investigate the frequency of movement of laying hens between indoor and outdoor enclosures and the time hens spent outside the hen house in relation to feather pecking and condition of the integument. The effect of housing condition and the genotype were studied. Hens that were offered a large space to outside open area (10m²/bird) moved significantly more frequently to the outdoor areas than others (2.5m²/bird). Frequency of movement between poultry house and winter garden was higher in the group without grassland. Hens kept at a higher density outdoors (2.5m²/bird) spent significantly more time in this area than hens were kept at a lower density (10m²/bird) on grassland. The high rates of feather pecking are observed in the group without grassland compared to groups stocked at 2.5m² or 10m² per bird on grassland The group without grassland had poorer feather condition compared to other groups that had 2.5m²/bird and 10m²/bird on grassland Lohmann Selected Leghorn (LSL) hens moved more frequently to the outdoor enclosures compared to Lohmann Tradition (LT). But LT hens spent significantly more time on grassland than LSL.The plumage condition was worse in LSL than LT hens. It is concluded that housing conditions might have a stronger influence on the development of feather pecking than the genetic aspect. Large differences between the genotypes examined were found in respect to the frequency of movement to the outdoor areas, the time spent outside and plumage and skin damage.

The sexes have different life histories that can influence their parental care strategies. I studied northern flicker, Colaptes auratus, parents and simultaneously radio-tracked mates during the nestling and post-fledging periods. I tested hypotheses about sex differences in parental care strategies by examining foraging patterns, provisioning effort and habitat use. Males and females used the same microhabitats, but avoided overlap of their foraging areas on the home range consistent with the hypothesis that mates separate the home range to reduce competition. During temporary (i.e., 24 hr) brood size manipulations, both parents decreased provisioning to reduced broods, but did not increase provisioning to enlarged broods or alter their foraging pattern on the landscape. I suggest flickers were energy limited and were incapable or unwilling to respond to increased brood demands. During the post-fledging period, males spent more time near their fledglings, and cared for their fledglings longer than females (16 days versus 12 days, respectively). Approximately 36% of females abandoned their brood in the post-fledging period and females with high levels of feather corticosterone were more likely to abandon. Older males and those with high provisioning rates in the nestling period fed their fledglings longer. Nearly 45% of fledglings died within the first week after leaving the nest, but survival was higher for fledglings with intermediate body mass and those that occupied areas of dense cover. Families moved a greater distance from the nest during the first 4 days post-fledging when there was less tree cover within 250 m of the nest site. Parents brought fledglings to areas with dense vegetation within the first week post-fledging, but subsequently shifted to open grassland habitats. My results show that parents invest in their offspring indirectly by taking them to habitats that increase survival. This research stresses the importance of studying parental care during the post-fledging period to gain a more complete understanding of the total parental investment of males versus females and how each sex may react differently to trade-offs between investing in the current brood versus self-maintenance.

Orientador: Edivaldo Antônio Garcia / Resumo: O estudo teve por objetivo comparar as idades e os níveis de debicagem por lâmina quente, em codornas japonesas, avaliando os resultados de desempenho durante as fases de crescimento e produção de ovos bem como sua qualidade. Foram utilizadas 770 codornas japonesas (Coturnix coturnix japonica) de um dia de idade para a fase de cria e recria (1-35 dias de idade), distribuídas em um delineamento inteiramente casualizado, composto por sete tratamentos com cinco repetições de 22 aves cada, sendo os tratamentos: aves não debicadas (ND), aves debicadas por cauterização de aproximadamente 1/3 aos 14 dias de idade (C.MOD 14), aves debicadas por cauterização de aproximadamente 1/3 aos 28 dias de idade (C.MOD 28), aves debicadas de forma moderada, com corte de aproximadamente 1/3 do bico aos 14 dias de idade (D.MOD 14), aves debicadas de forma moderada, com corte de aproximadamente 1/3 do bico aos 28 dias de idade (D.MOD 28), aves debicadas de forma severa, com corte aproximadamente de 1/3-1/2 do bico aos 14 dias de idade (D.SEV 14) e aves debicadas de forma severa, com corte aproximadamente de 1/3-1/2 do bico aos 28 dias de idade (D.SEV 28). A fase de produção compreendeu o período de 36 dias às 37ª semanas de idade, adotando-se o mesmo delineamento experimental utilizado na fase inicial, entretanto com 18 codornas por unidade experimental, totalizando 630 aves. Nas condições de execução desta pesquisa, os métodos de debicagem efetuados aos 14 e 28 dias de idade, não influenciaram o d... (Resumo completo, clicar acesso eletrônico abaixo) / Mestre

Queratinases alcalinas apresentam um interessante potencial para utilização em processos de hidrólises de proteínas, particularmente na quebra de resíduos de queratina para obter produtos de melhor valor. Uma bactéria queratinolítica, previamente isolada do intestino de peixe Piaractus mesopotamicus da bacia Amazônica foi identificada como sendo Bacillus sp. P7. Esta linhagem foi capaz de degradar penas e farinha de penas durante cultivos submersos, com a concomitante produção de queratinases extracelulares e com o aumento da concentração de proteínas solúveis no meio. O meio de cultivo para a produção da queratinase continha farinha de pena como única fonte de carbono, nitrogênio e enxofre. A purificação da enzima envolveu as etapas de precipitação com sulfato de amônio e cromatografias de gel-filtração e de troca-iônica. Após as referidas etapas, a enzima apresentou um fator de purificação de 29,8 vezes e um rendimento de 27%. A análise do zimograma revelou 2 bandas proteolíticas. A queratinase parcialmente purificada apresentou atividade ótima em pH 9,0 e 55 °C. A atividade da enzima foi estimulada por Ca²+, Mg²+ e Sr²+, e reduzida por Hg²+, Cu²+, Zn²+ e Co²+. Os solventes ß-mercaptoetanol e Triton X-100 afetaram ligeiramente a atividade da enzima, ao passo que SDS estimulou a atividade enzimática. PMSF e ácido etilenodiaminotetracétio (EDTA) inibiram a atividade queratinolítica nos ensaios enzimáticos, sugerindo uma característica de serina protease, requerendo íons metálicos para a máxima atividade e/ou estabilidade. Tais queratinases alcalinas podem ser empregadas nas formulações de detergentes, no processamento do couro e nos processos de hidrólise protéica, especificamente na quebra de resíduos queratinosos para obter produtos de melhor valor. / Alkaline keratinases offer an interesting potential for utilization in processes of protein hydrolysis, particularly in the breakdown of keratin wastes in view to obtain added-value products. A keratinolytic bacterium was previously isolated from intestines of the Amazon basin fish Piaractus mesopotamicus and was identified as Bacillus sp. P7. This strain degraded feather meal and whole feathers during submerged cultivations, with the concomitant production of extracellular keratinolytic enzymes and the increase in soluble protein. The medium for keratinase production contained feather meal as the only source of carbon, nitrogen and sulphur. Enzyme purification was carried out by ammonium sulphate precipitation and sequential gel-filtration and ion-exchange chromatographies. The purification was about 29.8-fold, with a yield of 27%. Zymogram analysis revealed two proteolytic bands. The partially purified keratinase had optimal activity at pH 9.0 and 55 °C. Enzyme activity was stimulated by Ca²+, Mg²+ and Sr²+, and reduced by Hg²+, Cu²+, Zn²+ and Co²+. Solvents, ß-mercaptoethanol and Triton X-100 slightly affected, whereas SDS stimulated the enzyme activity. PMSF and ethylenediaminetetraacetic acid (EDTA) inhibited keratinase activity in enzyme assays, suggesting its major serine protease feature, requiring metallic ions for maximum activity/stability. Such alkaline keratinase might be employed in detergent formulations, in leather processing, and in processes of protein hydrolysis, specifically the breakdown of keratin wastes to obtain value-added products.

Queratinases alcalinas apresentam um interessante potencial para utilização em processos de hidrólises de proteínas, particularmente na quebra de resíduos de queratina para obter produtos de melhor valor. Uma bactéria queratinolítica, previamente isolada do intestino de peixe Piaractus mesopotamicus da bacia Amazônica foi identificada como sendo Bacillus sp. P7. Esta linhagem foi capaz de degradar penas e farinha de penas durante cultivos submersos, com a concomitante produção de queratinases extracelulares e com o aumento da concentração de proteínas solúveis no meio. O meio de cultivo para a produção da queratinase continha farinha de pena como única fonte de carbono, nitrogênio e enxofre. A purificação da enzima envolveu as etapas de precipitação com sulfato de amônio e cromatografias de gel-filtração e de troca-iônica. Após as referidas etapas, a enzima apresentou um fator de purificação de 29,8 vezes e um rendimento de 27%. A análise do zimograma revelou 2 bandas proteolíticas. A queratinase parcialmente purificada apresentou atividade ótima em pH 9,0 e 55 °C. A atividade da enzima foi estimulada por Ca²+, Mg²+ e Sr²+, e reduzida por Hg²+, Cu²+, Zn²+ e Co²+. Os solventes ß-mercaptoetanol e Triton X-100 afetaram ligeiramente a atividade da enzima, ao passo que SDS estimulou a atividade enzimática. PMSF e ácido etilenodiaminotetracétio (EDTA) inibiram a atividade queratinolítica nos ensaios enzimáticos, sugerindo uma característica de serina protease, requerendo íons metálicos para a máxima atividade e/ou estabilidade. Tais queratinases alcalinas podem ser empregadas nas formulações de detergentes, no processamento do couro e nos processos de hidrólise protéica, especificamente na quebra de resíduos queratinosos para obter produtos de melhor valor. / Alkaline keratinases offer an interesting potential for utilization in processes of protein hydrolysis, particularly in the breakdown of keratin wastes in view to obtain added-value products. A keratinolytic bacterium was previously isolated from intestines of the Amazon basin fish Piaractus mesopotamicus and was identified as Bacillus sp. P7. This strain degraded feather meal and whole feathers during submerged cultivations, with the concomitant production of extracellular keratinolytic enzymes and the increase in soluble protein. The medium for keratinase production contained feather meal as the only source of carbon, nitrogen and sulphur. Enzyme purification was carried out by ammonium sulphate precipitation and sequential gel-filtration and ion-exchange chromatographies. The purification was about 29.8-fold, with a yield of 27%. Zymogram analysis revealed two proteolytic bands. The partially purified keratinase had optimal activity at pH 9.0 and 55 °C. Enzyme activity was stimulated by Ca²+, Mg²+ and Sr²+, and reduced by Hg²+, Cu²+, Zn²+ and Co²+. Solvents, ß-mercaptoethanol and Triton X-100 slightly affected, whereas SDS stimulated the enzyme activity. PMSF and ethylenediaminetetraacetic acid (EDTA) inhibited keratinase activity in enzyme assays, suggesting its major serine protease feature, requiring metallic ions for maximum activity/stability. Such alkaline keratinase might be employed in detergent formulations, in leather processing, and in processes of protein hydrolysis, specifically the breakdown of keratin wastes to obtain value-added products.

Submitted by JÉSSICA MORAES CRUVINEL null (jessicacruvinel@gmail.com) on 2018-02-01T11:41:26Z No. of bitstreams: 1 DEFESA 2018 JESSICA COM FICHA.pdf: 1166949 bytes, checksum: e95e63955a4ec2713ec05e241c46eed6 (MD5) / Rejected by Maria Lucia Martins Frederico null (mlucia@fca.unesp.br), reason: Prezada 1 - Complete a ficha catalográfica inserindo o título na integra : Debicagem em Codornas Japonesas (Coturnix coturnix japonica) 2 - Complete a Agencia de fomento uma vez que inseriu nos Agradecimentos ... "A Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), pela concessão de bolsa de estudo" on 2018-02-01T16:43:56Z (GMT) / Submitted by JÉSSICA MORAES CRUVINEL null (jessicacruvinel@gmail.com) on 2018-02-01T23:32:35Z No. of bitstreams: 1 DEFESA 2018 JESSICA COM FICHA.pdf: 1166949 bytes, checksum: e95e63955a4ec2713ec05e241c46eed6 (MD5) / Approved for entry into archive by Maria Lucia Martins Frederico null (mlucia@fca.unesp.br) on 2018-02-05T11:30:52Z (GMT) No. of bitstreams: 1 cruvinel_jm_me_bot.pdf: 1166949 bytes, checksum: e95e63955a4ec2713ec05e241c46eed6 (MD5) / Made available in DSpace on 2018-02-05T11:30:52Z (GMT). No. of bitstreams: 1 cruvinel_jm_me_bot.pdf: 1166949 bytes, checksum: e95e63955a4ec2713ec05e241c46eed6 (MD5) Previous issue date: 2018-01-19 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O estudo teve por objetivo comparar as idades e os níveis de debicagem por lâmina quente, em codornas japonesas, avaliando os resultados de desempenho durante as fases de crescimento e produção de ovos bem como sua qualidade. Foram utilizadas 770 codornas japonesas (Coturnix coturnix japonica) de um dia de idade para a fase de cria e recria (1-35 dias de idade), distribuídas em um delineamento inteiramente casualizado, composto por sete tratamentos com cinco repetições de 22 aves cada, sendo os tratamentos: aves não debicadas (ND), aves debicadas por cauterização de aproximadamente 1/3 aos 14 dias de idade (C.MOD 14), aves debicadas por cauterização de aproximadamente 1/3 aos 28 dias de idade (C.MOD 28), aves debicadas de forma moderada, com corte de aproximadamente 1/3 do bico aos 14 dias de idade (D.MOD 14), aves debicadas de forma moderada, com corte de aproximadamente 1/3 do bico aos 28 dias de idade (D.MOD 28), aves debicadas de forma severa, com corte aproximadamente de 1/3-1/2 do bico aos 14 dias de idade (D.SEV 14) e aves debicadas de forma severa, com corte aproximadamente de 1/3-1/2 do bico aos 28 dias de idade (D.SEV 28). A fase de produção compreendeu o período de 36 dias às 37ª semanas de idade, adotando-se o mesmo delineamento experimental utilizado na fase inicial, entretanto com 18 codornas por unidade experimental, totalizando 630 aves. Nas condições de execução desta pesquisa, os métodos de debicagem efetuados aos 14 e 28 dias de idade, não influenciaram o desempenho de codornas na fase inicial, na fase de produção e a qualidade dos ovos, entretanto, as debicagens efetuadas aos 14 dias e também de modo severo aos 28 dias de idade foram mais eficientes no controle de arranque de penas. / The aim of this study was to compare the ages and levels of hot blade beak trimming in Japanese quails evaluating their performance during the rearing and production phases as well as their egg quality. Seven hundred seventy (770) Japanese quails (Coturnix coturnix japonica) of one day of age for the rearing phase (1-35 days of age) were used and distributed in a completely randomized design, with seven treatments, five replicates of 22 birds each. The treatments were: not trimmed birds (ND), cauterization of about one-third of the beak at 14 days of age (C.MOD 14), cauterization of about one-third of the beak at 28 days of age (C.MOD 28), moderately beak trimming, removing approximately 1/3 of the beak at 14 days of age (D.MOD 14), moderately beak trimming, removing approximately 1/3 of the beak at 28 days of age (D.MOD 28), severe beak trimming, removing approximately 1/3 to 1/2 of the beak at 14 days of age (D.SEV 14) and severe trimming, removing approximately 1/3 to 1/2 of the beak at 28 days of age (D.SEV 28). The production phase comprised the period of 36 days at 37 weeks of age, adopting the same experimental design used in the breeding and rearing phase, however, with 18 quails were alloted per experimental unit, total of 630 quails. Under the conditions of execution of this research, the methods of beak trimming at 14 and 28 days of age did not influence the performance of quails in the initial, in the production phase and egg quality, however, the beak trimming conducted at 14 days and also severe at 28 days of age were more efficient in the control of feather pecking.

Queratinases alcalinas apresentam um interessante potencial para utilização em processos de hidrólises de proteínas, particularmente na quebra de resíduos de queratina para obter produtos de melhor valor. Uma bactéria queratinolítica, previamente isolada do intestino de peixe Piaractus mesopotamicus da bacia Amazônica foi identificada como sendo Bacillus sp. P7. Esta linhagem foi capaz de degradar penas e farinha de penas durante cultivos submersos, com a concomitante produção de queratinases extracelulares e com o aumento da concentração de proteínas solúveis no meio. O meio de cultivo para a produção da queratinase continha farinha de pena como única fonte de carbono, nitrogênio e enxofre. A purificação da enzima envolveu as etapas de precipitação com sulfato de amônio e cromatografias de gel-filtração e de troca-iônica. Após as referidas etapas, a enzima apresentou um fator de purificação de 29,8 vezes e um rendimento de 27%. A análise do zimograma revelou 2 bandas proteolíticas. A queratinase parcialmente purificada apresentou atividade ótima em pH 9,0 e 55 °C. A atividade da enzima foi estimulada por Ca²+, Mg²+ e Sr²+, e reduzida por Hg²+, Cu²+, Zn²+ e Co²+. Os solventes ß-mercaptoetanol e Triton X-100 afetaram ligeiramente a atividade da enzima, ao passo que SDS estimulou a atividade enzimática. PMSF e ácido etilenodiaminotetracétio (EDTA) inibiram a atividade queratinolítica nos ensaios enzimáticos, sugerindo uma característica de serina protease, requerendo íons metálicos para a máxima atividade e/ou estabilidade. Tais queratinases alcalinas podem ser empregadas nas formulações de detergentes, no processamento do couro e nos processos de hidrólise protéica, especificamente na quebra de resíduos queratinosos para obter produtos de melhor valor. / Alkaline keratinases offer an interesting potential for utilization in processes of protein hydrolysis, particularly in the breakdown of keratin wastes in view to obtain added-value products. A keratinolytic bacterium was previously isolated from intestines of the Amazon basin fish Piaractus mesopotamicus and was identified as Bacillus sp. P7. This strain degraded feather meal and whole feathers during submerged cultivations, with the concomitant production of extracellular keratinolytic enzymes and the increase in soluble protein. The medium for keratinase production contained feather meal as the only source of carbon, nitrogen and sulphur. Enzyme purification was carried out by ammonium sulphate precipitation and sequential gel-filtration and ion-exchange chromatographies. The purification was about 29.8-fold, with a yield of 27%. Zymogram analysis revealed two proteolytic bands. The partially purified keratinase had optimal activity at pH 9.0 and 55 °C. Enzyme activity was stimulated by Ca²+, Mg²+ and Sr²+, and reduced by Hg²+, Cu²+, Zn²+ and Co²+. Solvents, ß-mercaptoethanol and Triton X-100 slightly affected, whereas SDS stimulated the enzyme activity. PMSF and ethylenediaminetetraacetic acid (EDTA) inhibited keratinase activity in enzyme assays, suggesting its major serine protease feature, requiring metallic ions for maximum activity/stability. Such alkaline keratinase might be employed in detergent formulations, in leather processing, and in processes of protein hydrolysis, specifically the breakdown of keratin wastes to obtain value-added products.