Draft genome sequence of Streptomyces sp. strain F1, a potential source for glycoside hydrolases isolated from Brazilian soil

ABSTRACT Here, we show the draft genome sequence of Streptomyces sp. F1, a strain isolated from soil with great potential for secretion of hydrolytic enzymes used to deconstruct cellulosic biomass. The draft genome assembly of Streptomyces sp. strain F1 has 69 contigs with a total genome size of 8,142,296 bp and G + C 72.65%. Preliminary genome analysis identified 175 proteins as Carbohydrate-Active Enzymes, being 85 glycoside hydrolases organized in 33 distinct families. This draft genome information provides new insights on the key genes encoding hydrolytic enzymes involved in biomass deconstruction employed by soil bacteria.

Beta-1,3 Glucanases e quitinases: aplicação na lise de leveduras e inibição de fungos / Beta-1,3 glucanases and chitinases: application in the yeast cell lysis and fungi inhibition

Objetivou-se, no presente trabalho, a aplicação de β-1,3 glucanases e quitinases da linhagem Cellulosimicrobium cellulans 191 na lise de leveduras e inibição de fungos, respectivamente. O delineamento experimental mostrou que as melhores condições para a lise de Saccharomyces cerevisiae KL-88 pela β-1,3 glucanase foi pH 6,5 e 35ºC. As células de leveduras incubadas por 10 h em frascos sem agitação mostraram-se mais susceptíveis à lise pela ação da enzima. Foi obtido maior lise da levedura quando a suspensão de células foi submetida ao tratamento com β-1,3 glucanase e cisteína 1mM. A enzima invertase intracelular ou ligada à célula de S. cerevisiae KL-88 e K. marxianus NCYC 587 foi extraída após tratamento da suspensão celular com β-1,3 glucanase, sendo que o tratamento prévio das leveduras com a enzima aumentou a susceptibilidade das células à lise com ultra-som. A preparação de quitinase foi capaz de formar halos de inibição de alguns fungos.

The aim of this work was the application of β-1,3 glucanases and chitinases by Cellulosimicrobium cellulans 191 strain on yeast cell lysis and fungi inhibition, respectively. The experimental design study showed that the best conditions to Saccharomyces cerevisiae KL-88 lysis by β-1,3 glucanase extract were pH 6,5 and 35ºC. This study also demonstrated that the yeast cells were more susceptible to lysis after 10 h of cultivation in flasks without agitation. Lysis activity was increased when S. cerevisiae KL-88 cell suspension was treated with β-1,3 glucanase and cystein 1mM. The enzyme invertase of S. cerevisiae KL-88 and Kluyveromyces marxianus NCYC 587 was extracted after treatment of cell suspension with β-1,3 glucanase and the previous treatment of yeasts with the enzyme, increased the susceptibility to lysis when ultrasonic treatment was used. The chitinase presented growth inhibition halos for some of the fungi.

Optimization of medium composition for transglutaminase production by a Brazilian soil Streptomyces sp

Finding a new microbial source of transglutaminase (MTGase) and the study of the medium composition for MTGase production were the goals of this work. A total of 200 actinomycete-like strains were isolated from Brazilian soil samples and two of them named T10b and P20 were selected based on their ability to produce 0.15 U.mL-1 and 0.25 U.mL-1 of MTGase, respectively. Strain P20 was chosen to continue the study and was identified as Streptomyces sp. In order to optimize the MTGase activity, modifications of the usual media composition described for enzyme production were tested. The strategy adopted was: (1) screening experiment for the best carbon and nitrogen sources; (2) fractional factorial design (FFD) to elucidate the key ingredients in the media (the results indicated that the soybean flour, peptone, KH2PO4 and MgSO4.7H2O had a significant effect on MTGase) production and (3) central composite design (CCD) to optimize the concentration of the key components. The experimental results were fitted to a second-order polynomial model at the 95 percent level of significance (P < 0.05). Under the proposed optimized conditions, the model predicted a MTGase activity of 1.37 U.mL-1, very closely matching the experimental activity of 1.4 U.mL-1.

Application of response surface methodology for glucosyltransferase production and conversion of sucrose into isomaltulose using free Erwinia sp. cells

Isomaltulose is a structural isomer of sucrose commercially used in food industries. Glucosyltransferase produced by Erwinia sp. D12 catalyses an intramolecular transglucosylation of sucrose giving isomaltulose. The Experimental design and response surface methodology were applied for the optimization of the nutrient concentration in the culture medium for the enzyme production in shaken flasks at 200 rpm and 30°C. The three variables involved in this study were sugar cane molasses, bacteriological peptone and yeast extract Prodex Lac SD®. The statistical analysis of the results showed that, in the range studied, all the factors had a significant effect (p < 0.05) on glucosyltransferase production and the highest enzyme activity was observed in culture medium containing sugar cane molasses (160 g/L), bacteriological peptone (20 g/L) and yeast extract Prodex Lac SD® (15 g/L). Maximum glucosyltransferase activity of 29.88 U/mL was achieved in a 6.6-L fermenter using the optimized medium. Free Erwinia sp. D12 cells were used for isomaltulose production from sucrose during fifteen successive batches. The final isomaltulose concentration of 75.6 percent obtained in the first batch increased to 77.21 percent (mean value) in the other fourteen batches and the productivity of 1.1 g/L x hr was obtained in batch process.

Production of glucosyltransferase by Erwinia sp. using experimental design and response surface methodology

A glicosiltransferase obtida pela linhagem Erwinia sp. é uma enzima intracelular que catalisa a conversão de sacarose em isomaltulose. A isomaltulose é um dissacarídeo redutor, não cariogênico e comercialmente utilizado em alimentos como substituto da sacarose. A metodologia de superfície de resposta e planejamento fatorial composto central-23 foram utilizados para otimizar o meio de cultivo para a producão de glicosiltransferase de Erwinia sp. em frascos sob agitacão a 200 rpm e 30ºC. As três variáveis independentes envolvidas no estudo foram o melaco de cana de acúcar, a água de maceracão de milho e o extrato de levedura Prodex Lac SD. As análises estatísticas dos resultados mostraram que, dentro da faixa estudada das concentracões dos componentes de meio de cultivo, todas as variáveis apresentaram efeito significativo na producão de glicosiltransferase. O meio de cultivo otimizado foi composto de 100 gL-1 de melaco de cana de acúcar, 60 gL-1 de água de maceracão de milho e 8 gL-1 de extrato de levedura Prodex Lac SD, apresentando atividade de glicosiltransferase de 6.65 U mL-1.