Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-02-21T00:14:47Z No. of bitstreams: 1 YagoQueirozDosSantos_DISSERT.pdf: 1419350 bytes, checksum: 3ae7b369d8ed52af2d85454e8aa5fdbb (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-03-03T21:49:39Z (GMT) No. of bitstreams: 1 YagoQueirozDosSantos_DISSERT.pdf: 1419350 bytes, checksum: 3ae7b369d8ed52af2d85454e8aa5fdbb (MD5) / Made available in DSpace on 2017-03-03T21:49:40Z (GMT). No. of bitstreams: 1 YagoQueirozDosSantos_DISSERT.pdf: 1419350 bytes, checksum: 3ae7b369d8ed52af2d85454e8aa5fdbb (MD5) Previous issue date: 2016-06-16 / A atual demanda por fontes de energia renov?veis tem impulsionado a busca de alternativas capazes de substituir o uso de combust?veis f?sseis. Uma das inova??es mais promissoras para impactar positivamente o cen?rio mundial de energia ? a produ??o de bioetanol de segunda gera??o (B2G), derivado de monossacar?deos obtidos a partir da degrada??o enzim?tica de material lignocelul?sico que normalmente ? descartado nos atuais processos agroindustriais. No presente trabalho, uma celulase halotolerante secretada por uma linhagem marinha Bacillus sp. SR22 com grande resist?ncia ?s mudan?as de temperatura e pH foi isolada e caracterizada. A endoglucanase de massa aproximada de 37.35 kDa nomeada como Bc22Cel foi purificada por precipita??o de sulfato de am?nio, cromatografia de gel filtra??o e extra??o do gel ap?s eletroforese em gel de poliacrilamida em condi??es nativas. O valor ideal de pH e temperatura de Bc22Cel foram 6,5 e 60 ? C, respectivamente. A enzima purificada demonstrou consider?vel propriedade halof?lica ao manter mais de 70% de atividade residual mesmo quando pr?-incubadas com 1,5 M de NaCl durante 1 hora. Ap?s a an?lise cin?tica de enzima purificada os valores de Km e Vmax foram estabelecidos em 0,3953 nmol.ml-1 e 0,0167 ?mol.ml-1.min-1, respectivamente. Avaliados conjuntamente, os presentes dados apontam a Bc22Cel como uma candidata potencial para aplica??es industriais de degrada??o de celulose. / The current demand for environment-friendly renewable energy sources has driven the search for alternatives capable of replacing the use of fossil fuels. One of the most promising innovations to positively impact the world energy scenario is the second-generation bioethanol production (B2G) from reducing sugars derived from enzymatic degradation of lignocellulosic material that is ordinarily discarded at agroindustrial processes. In this work, a salt-tolerant cellulase secreted by a marine Bacillus sp. SR22 strain with wide resistance to temperature and pH was isolated and characterized. The 37.35 kDa endoglucanase named as Bc22Cel was purified by ammonium sulphate precipitation, gel filtration chromatography and extraction from the gel after non-reducing sodium dodecylsufate-polyacrylamide gel electrophoresis. The optimal pH value and temperature of Bc22Cel were 6.5 and 60 ?C, respectively. The purified Bc22Cel showed a considerable halophilic property being able to maintain more than 70% of residual activity even when pre-incubated with 1.5 M NaCl for 1 hour. Kinetic analysis of purified enzyme showed the Km and Vmax to be 0,3953 nmol ml-1 and 0,0167 ?mol ml-1 min-1, respectively. Taking together, the present data indicates the Bc22Cel as a potential and useful candidate for industrial applications.