Descoloração do corante Azul Brilhante de Remazol R por leveduras isoladas de moluscos do Rio Subaé, no estado da Bahia, Brasil

RESUMO Os objetivos deste trabalho foram estudar o potencial de descoloração do corante Azul Brilhante de Remazol R (RBBR) por cinco isolados de leveduras identificados como OJU2, SJL6, SF5, SJ10 e SJU5, otimizar as condições de crescimento das leveduras e verificar a toxicidade do produto obtido após a descoloração. Para isso, foram realizados ensaios em batelada variando os seguintes parâmetros: pH (2 a 8), concentração de glicose (0 a 3%), concentração do corante (25 a 100 ppm) e temperatura (20 a 40ºC). As leveduras mostraram capacidade de descolorir o RBBR com eficiência entre 80 e 93%, depois de 24 horas. A melhor condição para descoloração do RBBR ocorreu em pH ácido, 2% de glicose, 25 ppm do corante e 25ºC. Com os ensaios com Artemia salina, foi observado diminuição da toxicidade após tratamento com os isolados SJ10 e SJU5, depois de 120 horas de incubação

A Comparative Study of Code Type Models as an Illustration of a Guide for the Engineer

info:eu-repo/semantics/publishe

Sporadic Distribution of tRNA _CCU ^Arg Introns among α-Purple Bacteria: Evidence for Horizontal Transmission and Transposition of a Group I Intron

ABSTRACT A group I intron interrupts the tRNA CCU Arg gene of the α-purple bacterium Agrobacterium tumefaciens (B. Reinhold-Hurek and D. A. Shub, Nature [London] 357:173–176, 1992). In this study, we assess the distribution of the corresponding intron among 12 additional species of α-purple bacteria. Of 10 newly identified tRNA CCU Arg genes, we found only two that contained an intron homologous to that of the Agrobacterium tRNA CCU Arg intron. This restricted and scattered distribution of the tRNA CCU Arg intron among α-purple bacteria is consistent with a recent origin and horizontal transmission. Primary and secondary structural similarities between tRNA UAA Leu introns found in strains of the cyanobacterium Microcystis aeruginosa (K. Rudi and K. S. Jacobsen, FEMS Microbiol. Lett. 156:293–298, 1997) and α-purple tRNA CCU Arg introns suggest that these introns share a more recent common ancestor than either does with other known cyanobacterial tRNA UAA Leu introns. </jats:p

Transformation of Industrial Dyes by Manganese Peroxidases from <i>Bjerkandera adusta</i> and <i>Pleurotus eryngii</i> in a Manganese-Independent Reaction

ABSTRACT We investigated the transformation of six industrial azo and phthalocyanine dyes by ligninolytic peroxidases from Bjerkandera adusta and other white rot fungi. The dyes were not oxidized or were oxidized very little by Phanerochaete chrysosporium manganese peroxidase (MnP) or by a chemically generated Mn 3+ -lactate complex. Lignin peroxidase (LiP) from B. adusta also showed low activity with most of the dyes, but the specific activities increased 8- to 100-fold when veratryl alcohol was included in the reaction mixture, reaching levels of 3.9 to 9.6 U/mg. The B. adusta and Pleurotus eryngii MnP isoenzymes are unusual because of their ability to oxidize aromatic compounds like 2,6-dimethoxyphenol and veratryl alcohol in the absence of Mn 2+ . These MnP isoenzymes also decolorized the azo dyes and the phthalocyanine complexes in an Mn 2+ -independent manner. The reactions with the dyes were characterized by apparent K m values ranging from 4 to 16 μM and specific activities ranging from 3.2 to 10.9 U/mg. Dye oxidation by these peroxidases was not increased by adding veratryl alcohol as it was in LiP reactions. Moreover, the reaction was inhibited by the presence of Mn 2+ , which in the case of Reactive Black 5, an azo dye which is not oxidized by the Mn 3+ -lactate complex, was found to act as a noncompetitive inhibitor of dye oxidation by B. adusta MnP1. </jats:p