Use of lignocellulose biomass for endoxylanase production by Streptomyces termitum.

Actinobacteria isolates from Brazilian Cerrado soil were evaluated for their ability to produce enzymes of the cellulolytic and xylanolytic complex using lignocellulose residual biomass. Preliminary semiquantitative tests, made in Petri plates containing carboxymethylcellulose and beechwood xylan, indicated 11 potential species producing enzymes, all belonging to the genus Streptomyces. The species were subsequently grown in pure substrates in submerged fermentation and analyzed for the production of enzymes endoglucanase, ß-glucosidase, endoxylanase, and ß-xylosidase. The best results were obtained for endoxylanase enzyme production with Streptomyces termitum(UFLA CES 93). The strain was grown on lignocellulose biomass (bagasse, straw sugarcane, and cocoa pod husk) that was used in natura or acid pretreated. The medium containing sugarcane bagasse in natura favored the production of the endoxylanase that was subsequently optimized through an experimental model. The highest enzyme production 0.387 U mL-1, (25.8 times higher), compared to the lowest value obtained in one of the trials, was observed when combining 2.75% sugar cane bagasse and 1.0 g L-1 of yeast extract to the alkaline medium (pH 9.7). This is the first study using S. termitum as a producer of endoxylanase.

Sugarcane bagasse hydrolysis using yeast cellulolytic enzymes.

Ethanol fuel production from lignocellulosic biomass is emerging as one of the most important technologies for sustainable development. To use this biomass, it is necessary to circumvent the physical and chemical barriers presented by the cohesive combination of the main biomass components, which hinders the hydrolysis of cellulose and hemicellulose into fermentable sugars. This study evaluated the hydrolytic capacity of enzymes produced by yeasts, isolated from the soils of the Brazilian Cerrado biome (savannah) and the Amazon region, on sugarcane bagasse pre-treated with H2SO4. Among the 103 and 214 yeast isolates from the Minas Gerais Cerrado and the Amazon regions, 18 (17.47%) and 11 (5.14%) isolates, respectively, were cellulase-producing. Cryptococcus laurentii was prevalent and produced significant ß- glucosidase levels, which were higher than the endo- and exoglucanase activities. In natura sugarcane bagasse was pre-treated with 2% H2SO4 for 30 min at 150oC. Subsequently, the obtained fibrous residue was subjected to hydrolysis using the Cryptococcus laurentii yeast enzyme extract for 72 h. This enzyme extract promoted the conversion of approximately 32% of the cellulose, of which 2.4% was glucose, after the enzymatic hydrolysis reaction, suggesting that C. laurentii is a good ß-glucosidase producer. The results presented in this study highlight the importance of isolating microbial strains that produce enzymes of biotechnological interest, given their extensive application in biofuel production.

Efeito do extrato do romã (Punica granatum) sobre bactérias cariogênicas: estudo in vitro e in vivo / Effect of pomegranate extract (Punica granatum) on cariogenic bacteria: in vitro and in vivo study

Objetivo: O objetivo deste trabalho foi avaliar o efeito inibitório de extratos de plantas sobre cepas de Streptococcus mutans in vitro e avaliar in vivo o potencial inibitório de dentifrício incorporado com o extrato de maior potencial sobre estreptococos do grupo mutans e sobre o índice de biofilme. Materiais e Métodos: Em meio de cultura inoculado com S. mutans (ATCC25175), depositaram-se extratos etanólicosde 32 plantas. Posteriormente, avaliaram-se os halos de inibição. As capacidades inibitórias foram: Ocimumgratissimum (flor) com 08 mm; Moringa oleífera (folha) 10 mm; Copaífera langsdorffi (folha) 16 mm e Punicagranatum (pericarpo desidratado) com 18 mm. Uma vez que este último extrato apresentou o maior halo de inibição, foi utilizado na fase seguinte. O extrato de romã (Punica granatum) foi incorporado em dentifrício, nas concentrações de 1% e 3% após determinação da concentração inibitória mínima. Estes foram testados em 30 voluntários divididos em 3 grupos (um para cada extrato e um grupo controle). Os voluntários fizeram uso dos dentifrícios durante 08 dias. A atividade antimicrobiana foi avaliada através da determinação do índice de biofilme e contagem de estreptococos do grupo mutans (UFC/ml). Resultados: Houve redução (p < 0,05) no índice de biofilme para o extrato a 3%, porém não houve diferença na contagem de microrganismos (p > 0,05). Conclusão: Conclui-se que a Punica granatum L. foi o extrato que apresentou maior atividade inibitória in vitro contra S. mutans. A formulação do dentifrício mostrou eficiência após oito dias de uso diminuindo significativamente o índice de biofilme, porém, não apresentou redução do número de estreptococos do grupo mutans.