small bowel biopsy specimen. No other pathogens were found. At the time of diagnosis the serum dr... more small bowel biopsy specimen. No other pathogens were found. At the time of diagnosis the serum drug level of itraconazole was 7.9 ,ug/ml (levels above 2.0 ,ug/ml are considered therapeutic). Albendazole and metronidazole were ineffective in ameliorating the patient's diarrhoea. Symptomatic therapy with tinctura opii and loperamide resulted in a decrease of the stool frequency to two to five bowel movements per day. The patient continues to excrete E bieneusi in his stool.
Comparative biochemistry and physiology. B, Comparative biochemistry, 1992
1. D-GPDH from HeLa cells was isolated and purified. 2. Some basic kinetic constants are reported... more 1. D-GPDH from HeLa cells was isolated and purified. 2. Some basic kinetic constants are reported. 3. Sodium dodecyl polyacrylamide gel electrophoresis gave a single band with a molecular weight of approximately 36 K. 4. ATP and NADH inhibit competitively enzyme activity. 5. Comparative catalytic properties of GPDH from normal and tumor cells were effectuated.
Twenty-Seventh Symposium on Biotechnology for Fuels and Chemicals, 2006
Cyclodextrin glycosyltransferase (CGTase) is an enzyme that produces cyclodextrins from starch by... more Cyclodextrin glycosyltransferase (CGTase) is an enzyme that produces cyclodextrins from starch by an intramolecular transglycosylation reaction. Cyclodextrins have been shown to have a number of applications in the food, cosmetic, pharmaceutical, and chemical industries. In the current study, the production of CGTase by Paenibacillus campinasensis strain H69-3 was examined in submerged and solid-state fermentations. P. campinasensis strain H69-3 was isolated from the soil, which grows at 45°C, and is a Gramvariable bacterium. Different substrate sources such as wheat bran, soybean bran, soybean extract, cassava solid residue, cassava starch, corn starch, and other combinations were used in the enzyme production. CGTase activity was highest in submerged fermentations with the greatest production observed at 48-72 h. The physical and chemical properties of CGTase were determined from the crude enzyme produced from submerged fermentations. The optimum temperature was found to be 70-75°C, and the activity was stable at 55°C for 1 h. The enzyme displayed two optimum pH values, 5.5 and 9.0 and was found to be stable between a pH of 4.5 and 11.0.
Cyclodextrin glucanotransferase production from Bacillus clausii E16, a new bacteria isolated fro... more Cyclodextrin glucanotransferase production from Bacillus clausii E16, a new bacteria isolated from Brazilian soil samples was optimized in shake-flask cultures. A 2(4) full-factorial central composite design was performed to optimize the culture conditions, using a response surface methodology. The combined effect among the soluble starch concentration, the peptone concentration, the yeast extract concentration, and the initial pH value of the culture medium was investigated. The optimum concentrations of the components, determined by a 2(4) full-factorial central composite design, were 13.4 g/L soluble starch, 4.9 g/L peptone, 5.9 g/L yeast extract, and initial pH 10.1. Under these optimized conditions, the maximum cyclodextrin glucanotransferase activity was 5.9 U/mL after a 48-h fermentation. This yield was 68% higher than that obtained when the microorganism was cultivated in basal culture medium.
The pectinolytic enzyme obtained from Penicillium viridicatum RFC by solid-state fermentation was... more The pectinolytic enzyme obtained from Penicillium viridicatum RFC by solid-state fermentation was purified to homogeneity by pretreatment with kaolin (40 mg mL À1 ) and ultrafiltration, followed by chromatography on a Sephadex G50 column. The apparent molecular weight of the enzyme was 24 kDa. Maximal activity occurred at pH 6.0 and at 60 8C. The enzyme proved to be an exo-polygalacturonase, releasing galacturonic acid by hydrolysis of highly esterified pectin. The presence of 10 mM Ba 2+ increased the enzyme activity by 96% and its thermal stability by 30%, besides increasing its stability at acid pH. The apparent K m with apple pectin as substrate was 1.82 mg mL À1 and the V max was 81 mmol min À1 mg À1 .
A fruta jambolão (Syzygium cumini Lamarck) é uma fruta de coloração roxa intensa e sabor agradáve... more A fruta jambolão (Syzygium cumini Lamarck) é uma fruta de coloração roxa intensa e sabor agradável. Dado que não há na literatura nenhum relato de seu aproveitamento industrial, a produção de geléia de jambolão tornou-se uma interessante atividade de pesquisa. Este trabalho objetivou a elaboração e a avaliação das características físico-químicas e sensoriais da geléia obtida do jambolão. A fruta apresentou a seguinte composição química: cinzas, 0,34%; lipídeos, 0,30%; proteínas, 0,67%; carboidratos, 10,07%; fibras, 0,28%; umidade, 87,75%; frutose, 0,4%; glicose, 0,6%; antocianinas totais, 0,276%; substâncias pécticas, 0,245%; acidez titulável, 5,91%; sólidos solúveis, 9,00%; e pH, 3,9. A geléia obtida apresentou a seguinte composição: açúcares redutores, 20,99%; não-redutores, 18,01%; açúcares totais, 39,00%; pH, 3,42; sólidos solúveis, 67ºBrix; acidez titulável, 5,47%; e umidade, 29,63%. A análise sensorial foi realizada por uma equipe de 50 provadores não treinados que avaliaram os atributos cor, aparência, odor, textura, sabor e avaliação global, pelo método de escala hedônica com nove pontos. Os resultados obtidos mostraram que o atributo cor foi o que mais agradou aos provadores, o atributo odor foi o menos apreciado. Em conclusão, o estudo de análise sensorial revelou uma aceitação satisfatória da geléia de jambolão. Palavras-chave: jambolão, geléia, antocianina, análise sensorial.
The alkalophilic bacteria Bacillus licheniformis 77-2 produces significant quantities of thermost... more The alkalophilic bacteria Bacillus licheniformis 77-2 produces significant quantities of thermostable cellulase-free xylanases. The crude xylanase was purified to apparent homogeneity by gel filtration (G-75) and ionic exchange chromatography (carboxymethyl sephadex, Q sepharose, and Mono Q), resulting in the isolation of two xylanases. The molecular masses of the enzymes were estimated to be 17 kDa (X-I) and 40 kDa (X-II),
UTILIZATION OF RESIDUAL LIQUID ORANGE FROM JUICE PROCESSING AS CULTIVA-TION MEDIUM OF PENICILLIUM... more UTILIZATION OF RESIDUAL LIQUID ORANGE FROM JUICE PROCESSING AS CULTIVA-TION MEDIUM OF PENICILLIUM CITRINUM: BIOLOGICAL DEPURATION OF THE RESI-DUE AND ENZYME PRODUCTION. Penicillium citrinum grown in orange juice processing wastes ...
Polygalacturonases production by newly isolated Monascus sp N8 and Aspergillus sp N12 strains was... more Polygalacturonases production by newly isolated Monascus sp N8 and Aspergillus sp N12 strains was carried out in solid-state fermentation using mixtures of wheat bran, sugar cane bagasse and orange bagasse as carbon sources. The maximal activity values of exo-polygalacturonases (exo-Pg) from Monascus sp and Aspergillus sp were obtained using wheat bran/sugar cane bagasse/orange bagasse mixture (6.6 U/mL) and wheat bran/orange
Wood-rotting fungi have the ability to degrade lignin by secreting ligninases, a promising enzyme... more Wood-rotting fungi have the ability to degrade lignin by secreting ligninases, a promising enzyme for degradation of environmental pollutants. Nine basidiomycete strains collected just outside the city of São José do Rio Preto, upstate São Paulo, Brazil, were evaluated for their manganese peroxidase (MnP), lignin peroxidase (LiP) and laccase production by solid-state fermentation on wheat bran.Datronia caperata SP381992,Polyporus tenuiculus SP381977
World Journal of Microbiology & Biotechnology, 2001
Five Bacillus strains isolated from decaying vegetable material were cultivated on wheat bran and... more Five Bacillus strains isolated from decaying vegetable material were cultivated on wheat bran and endo-polygalacturonases, exo-polygalacturonase and pectin lyase activities in the crude enzymatic solution obtained were determined. Highest activity was observed for all enzymes when fermentation was carried out at 28 °C, the highest activity values were obtained after 120 h of cultivation for exo-PG and after 48 h
Xylanases are enzymes of great industrial interest, mainly that it concerns to pulp and paper ind... more Xylanases are enzymes of great industrial interest, mainly that it concerns to pulp and paper industries, where they can be used as aid in bleaching process causing the reducing of added chemical. Xylanases degrade xylan and improve the access of chemicals to the lignin. In this work the xylanase produced by one newly selected bacterium, Bacillus sp called strain N.
ABSTRACT [P-B.108] Sugarcane bagasse saccharification by Myceliophthora sp F2.1.4and Aspergillus ... more ABSTRACT [P-B.108] Sugarcane bagasse saccharification by Myceliophthora sp F2.1.4and Aspergillus fumigatus M7.3 enzymatic extracts D.A. Bocchini-Martins∗, M.M.S. Moretti, M. Boscolo, R. Da Silva, E. Gomes IBILCE/UNESP, Brazil Keywords: Sugarcane bagasse; Saccharification; Myceliophthora; Aspergillus; Cellulases; Xylanases Cellulose and hemicellulose from sugarcane bagasse are a source of fermentable sugars. However, the complexity of lignocellulose represents an obstacle to sugarcane enzymatic degradation, so that pretreatments should be used to facilitate the enzymes access, improving hydrolysis. In this work, sugarcane bagasse saccharification by enzymatic extracts of two thermophilic fungi was evaluated. The enzymatic extracts from Myceliophthora sp F2.1.4 and Aspergillus fumigatus M7.3, obtained by solid state fermentation on lignocellulosic residues, were used and saccharification was performed at 50 ◦C, under 150 rpm, up to 72 h. Regarding “in natura” sugarcane bagasse, using the enzymatic extract from Myceliophthora sp F 2.1.4 (580 CMCase U/g of dry bagasse) or from A. fumigatus M7.3 (119,4 U/g of dry bagasse), 45,51 and 6,77mg of reducing sugar/g of bagasse were obtained after 48 h of hydrolysis, respectively. However, when bagasse pretreated with steam explosion was used, 80,78 and 31,8mg of reducing sugar/g of bagasse were obtained, under the same conditions, representing an increasing of 77,5 and 370% on sugar releasing, respectively. The increasing on hydrolysis time and on enzyme amount did not significantly improve saccharification. When CMCase and time of hydrolysis were fixed in 250 U/g of dry bagasse and 24 h, 57,5 and 22,8mg of reducing sugar/g of bagasse were obtained using A. fumigatus M7.3 or Myceliophthora sp F2.1.4 enzymatic extracts, respectively. Fromthese datawecan infer that the steam explosion pretreatment facilitated the enzymatic hydrolysis and that the enzymatic extract of A. fumigatus seems to be better than that from Myceliophthora on sugarcane bagasse hydrolysis. doi:10.1016/j.jbiotec.2010.08.461
A cyclomaltodextrin glucanotransferase (E.C. 2.4.1.19) from a newly isolated alkalophilic and mod... more A cyclomaltodextrin glucanotransferase (E.C. 2.4.1.19) from a newly isolated alkalophilic and moderately thermophilic Paenibacillus campinasensis strain H69-3 was purified as a homogeneous protein from culture supernatant. Cyclomaltodextrin glucanotransferase was produced during submerged fermentation at 45 degrees C and purified by gel filtration on Sephadex G50 ion exchange using a Q-Sepharose column and ion exchange using a Mono-Q column. The molecular weight of the purified enzyme was 70 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and the pI was 5.3. The optimum pH for enzyme activity was 6.5, and it was stable in the pH range 6.0-11.5. The optimum temperature was 65 degrees C at pH 6.5, and it was thermally stable up to 60 degrees C without substrate during 1 h in the presence of 10 mM CaCl(2). The enzyme activity increased in the presence of Co(2+), Ba(2+), and Mn(2+). Using maltodextrin as substrate, the K(m) and K(cat) were 1.65 mg/mL and 347.9 micromol/mg x min, respectively.
In this work, a 3 3 factorial design was performed with the aim of optimizing the culture conditi... more In this work, a 3 3 factorial design was performed with the aim of optimizing the culture conditions for xylanase production by an alkalophilic thermophilic strain of Bacillus circulans , using response surface methodology. The variables involved in this study were xylan concentration (X 1 ), pH (X 2 ) and cultivation time (X 3 ). The optimal response region was approached without using paths of steepest ascent. Statistical analysis of results showed that, in the range studied, only pH did not have a significant effect on xylanase production. A second-order model was proposed to represent the enzymic activity as a function of xylan concentration (X 1 ) and cultivation time (X 3 ). The optimum xylan concentration and cultivation time were 5 g/l and 48 h, respectively. Under these conditions, the model predicted a xylanase activity of 19.1 U/ml.
small bowel biopsy specimen. No other pathogens were found. At the time of diagnosis the serum dr... more small bowel biopsy specimen. No other pathogens were found. At the time of diagnosis the serum drug level of itraconazole was 7.9 ,ug/ml (levels above 2.0 ,ug/ml are considered therapeutic). Albendazole and metronidazole were ineffective in ameliorating the patient's diarrhoea. Symptomatic therapy with tinctura opii and loperamide resulted in a decrease of the stool frequency to two to five bowel movements per day. The patient continues to excrete E bieneusi in his stool.
Comparative biochemistry and physiology. B, Comparative biochemistry, 1992
1. D-GPDH from HeLa cells was isolated and purified. 2. Some basic kinetic constants are reported... more 1. D-GPDH from HeLa cells was isolated and purified. 2. Some basic kinetic constants are reported. 3. Sodium dodecyl polyacrylamide gel electrophoresis gave a single band with a molecular weight of approximately 36 K. 4. ATP and NADH inhibit competitively enzyme activity. 5. Comparative catalytic properties of GPDH from normal and tumor cells were effectuated.
Twenty-Seventh Symposium on Biotechnology for Fuels and Chemicals, 2006
Cyclodextrin glycosyltransferase (CGTase) is an enzyme that produces cyclodextrins from starch by... more Cyclodextrin glycosyltransferase (CGTase) is an enzyme that produces cyclodextrins from starch by an intramolecular transglycosylation reaction. Cyclodextrins have been shown to have a number of applications in the food, cosmetic, pharmaceutical, and chemical industries. In the current study, the production of CGTase by Paenibacillus campinasensis strain H69-3 was examined in submerged and solid-state fermentations. P. campinasensis strain H69-3 was isolated from the soil, which grows at 45°C, and is a Gramvariable bacterium. Different substrate sources such as wheat bran, soybean bran, soybean extract, cassava solid residue, cassava starch, corn starch, and other combinations were used in the enzyme production. CGTase activity was highest in submerged fermentations with the greatest production observed at 48-72 h. The physical and chemical properties of CGTase were determined from the crude enzyme produced from submerged fermentations. The optimum temperature was found to be 70-75°C, and the activity was stable at 55°C for 1 h. The enzyme displayed two optimum pH values, 5.5 and 9.0 and was found to be stable between a pH of 4.5 and 11.0.
Cyclodextrin glucanotransferase production from Bacillus clausii E16, a new bacteria isolated fro... more Cyclodextrin glucanotransferase production from Bacillus clausii E16, a new bacteria isolated from Brazilian soil samples was optimized in shake-flask cultures. A 2(4) full-factorial central composite design was performed to optimize the culture conditions, using a response surface methodology. The combined effect among the soluble starch concentration, the peptone concentration, the yeast extract concentration, and the initial pH value of the culture medium was investigated. The optimum concentrations of the components, determined by a 2(4) full-factorial central composite design, were 13.4 g/L soluble starch, 4.9 g/L peptone, 5.9 g/L yeast extract, and initial pH 10.1. Under these optimized conditions, the maximum cyclodextrin glucanotransferase activity was 5.9 U/mL after a 48-h fermentation. This yield was 68% higher than that obtained when the microorganism was cultivated in basal culture medium.
The pectinolytic enzyme obtained from Penicillium viridicatum RFC by solid-state fermentation was... more The pectinolytic enzyme obtained from Penicillium viridicatum RFC by solid-state fermentation was purified to homogeneity by pretreatment with kaolin (40 mg mL À1 ) and ultrafiltration, followed by chromatography on a Sephadex G50 column. The apparent molecular weight of the enzyme was 24 kDa. Maximal activity occurred at pH 6.0 and at 60 8C. The enzyme proved to be an exo-polygalacturonase, releasing galacturonic acid by hydrolysis of highly esterified pectin. The presence of 10 mM Ba 2+ increased the enzyme activity by 96% and its thermal stability by 30%, besides increasing its stability at acid pH. The apparent K m with apple pectin as substrate was 1.82 mg mL À1 and the V max was 81 mmol min À1 mg À1 .
A fruta jambolão (Syzygium cumini Lamarck) é uma fruta de coloração roxa intensa e sabor agradáve... more A fruta jambolão (Syzygium cumini Lamarck) é uma fruta de coloração roxa intensa e sabor agradável. Dado que não há na literatura nenhum relato de seu aproveitamento industrial, a produção de geléia de jambolão tornou-se uma interessante atividade de pesquisa. Este trabalho objetivou a elaboração e a avaliação das características físico-químicas e sensoriais da geléia obtida do jambolão. A fruta apresentou a seguinte composição química: cinzas, 0,34%; lipídeos, 0,30%; proteínas, 0,67%; carboidratos, 10,07%; fibras, 0,28%; umidade, 87,75%; frutose, 0,4%; glicose, 0,6%; antocianinas totais, 0,276%; substâncias pécticas, 0,245%; acidez titulável, 5,91%; sólidos solúveis, 9,00%; e pH, 3,9. A geléia obtida apresentou a seguinte composição: açúcares redutores, 20,99%; não-redutores, 18,01%; açúcares totais, 39,00%; pH, 3,42; sólidos solúveis, 67ºBrix; acidez titulável, 5,47%; e umidade, 29,63%. A análise sensorial foi realizada por uma equipe de 50 provadores não treinados que avaliaram os atributos cor, aparência, odor, textura, sabor e avaliação global, pelo método de escala hedônica com nove pontos. Os resultados obtidos mostraram que o atributo cor foi o que mais agradou aos provadores, o atributo odor foi o menos apreciado. Em conclusão, o estudo de análise sensorial revelou uma aceitação satisfatória da geléia de jambolão. Palavras-chave: jambolão, geléia, antocianina, análise sensorial.
The alkalophilic bacteria Bacillus licheniformis 77-2 produces significant quantities of thermost... more The alkalophilic bacteria Bacillus licheniformis 77-2 produces significant quantities of thermostable cellulase-free xylanases. The crude xylanase was purified to apparent homogeneity by gel filtration (G-75) and ionic exchange chromatography (carboxymethyl sephadex, Q sepharose, and Mono Q), resulting in the isolation of two xylanases. The molecular masses of the enzymes were estimated to be 17 kDa (X-I) and 40 kDa (X-II),
UTILIZATION OF RESIDUAL LIQUID ORANGE FROM JUICE PROCESSING AS CULTIVA-TION MEDIUM OF PENICILLIUM... more UTILIZATION OF RESIDUAL LIQUID ORANGE FROM JUICE PROCESSING AS CULTIVA-TION MEDIUM OF PENICILLIUM CITRINUM: BIOLOGICAL DEPURATION OF THE RESI-DUE AND ENZYME PRODUCTION. Penicillium citrinum grown in orange juice processing wastes ...
Polygalacturonases production by newly isolated Monascus sp N8 and Aspergillus sp N12 strains was... more Polygalacturonases production by newly isolated Monascus sp N8 and Aspergillus sp N12 strains was carried out in solid-state fermentation using mixtures of wheat bran, sugar cane bagasse and orange bagasse as carbon sources. The maximal activity values of exo-polygalacturonases (exo-Pg) from Monascus sp and Aspergillus sp were obtained using wheat bran/sugar cane bagasse/orange bagasse mixture (6.6 U/mL) and wheat bran/orange
Wood-rotting fungi have the ability to degrade lignin by secreting ligninases, a promising enzyme... more Wood-rotting fungi have the ability to degrade lignin by secreting ligninases, a promising enzyme for degradation of environmental pollutants. Nine basidiomycete strains collected just outside the city of São José do Rio Preto, upstate São Paulo, Brazil, were evaluated for their manganese peroxidase (MnP), lignin peroxidase (LiP) and laccase production by solid-state fermentation on wheat bran.Datronia caperata SP381992,Polyporus tenuiculus SP381977
World Journal of Microbiology & Biotechnology, 2001
Five Bacillus strains isolated from decaying vegetable material were cultivated on wheat bran and... more Five Bacillus strains isolated from decaying vegetable material were cultivated on wheat bran and endo-polygalacturonases, exo-polygalacturonase and pectin lyase activities in the crude enzymatic solution obtained were determined. Highest activity was observed for all enzymes when fermentation was carried out at 28 °C, the highest activity values were obtained after 120 h of cultivation for exo-PG and after 48 h
Xylanases are enzymes of great industrial interest, mainly that it concerns to pulp and paper ind... more Xylanases are enzymes of great industrial interest, mainly that it concerns to pulp and paper industries, where they can be used as aid in bleaching process causing the reducing of added chemical. Xylanases degrade xylan and improve the access of chemicals to the lignin. In this work the xylanase produced by one newly selected bacterium, Bacillus sp called strain N.
ABSTRACT [P-B.108] Sugarcane bagasse saccharification by Myceliophthora sp F2.1.4and Aspergillus ... more ABSTRACT [P-B.108] Sugarcane bagasse saccharification by Myceliophthora sp F2.1.4and Aspergillus fumigatus M7.3 enzymatic extracts D.A. Bocchini-Martins∗, M.M.S. Moretti, M. Boscolo, R. Da Silva, E. Gomes IBILCE/UNESP, Brazil Keywords: Sugarcane bagasse; Saccharification; Myceliophthora; Aspergillus; Cellulases; Xylanases Cellulose and hemicellulose from sugarcane bagasse are a source of fermentable sugars. However, the complexity of lignocellulose represents an obstacle to sugarcane enzymatic degradation, so that pretreatments should be used to facilitate the enzymes access, improving hydrolysis. In this work, sugarcane bagasse saccharification by enzymatic extracts of two thermophilic fungi was evaluated. The enzymatic extracts from Myceliophthora sp F2.1.4 and Aspergillus fumigatus M7.3, obtained by solid state fermentation on lignocellulosic residues, were used and saccharification was performed at 50 ◦C, under 150 rpm, up to 72 h. Regarding “in natura” sugarcane bagasse, using the enzymatic extract from Myceliophthora sp F 2.1.4 (580 CMCase U/g of dry bagasse) or from A. fumigatus M7.3 (119,4 U/g of dry bagasse), 45,51 and 6,77mg of reducing sugar/g of bagasse were obtained after 48 h of hydrolysis, respectively. However, when bagasse pretreated with steam explosion was used, 80,78 and 31,8mg of reducing sugar/g of bagasse were obtained, under the same conditions, representing an increasing of 77,5 and 370% on sugar releasing, respectively. The increasing on hydrolysis time and on enzyme amount did not significantly improve saccharification. When CMCase and time of hydrolysis were fixed in 250 U/g of dry bagasse and 24 h, 57,5 and 22,8mg of reducing sugar/g of bagasse were obtained using A. fumigatus M7.3 or Myceliophthora sp F2.1.4 enzymatic extracts, respectively. Fromthese datawecan infer that the steam explosion pretreatment facilitated the enzymatic hydrolysis and that the enzymatic extract of A. fumigatus seems to be better than that from Myceliophthora on sugarcane bagasse hydrolysis. doi:10.1016/j.jbiotec.2010.08.461
A cyclomaltodextrin glucanotransferase (E.C. 2.4.1.19) from a newly isolated alkalophilic and mod... more A cyclomaltodextrin glucanotransferase (E.C. 2.4.1.19) from a newly isolated alkalophilic and moderately thermophilic Paenibacillus campinasensis strain H69-3 was purified as a homogeneous protein from culture supernatant. Cyclomaltodextrin glucanotransferase was produced during submerged fermentation at 45 degrees C and purified by gel filtration on Sephadex G50 ion exchange using a Q-Sepharose column and ion exchange using a Mono-Q column. The molecular weight of the purified enzyme was 70 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and the pI was 5.3. The optimum pH for enzyme activity was 6.5, and it was stable in the pH range 6.0-11.5. The optimum temperature was 65 degrees C at pH 6.5, and it was thermally stable up to 60 degrees C without substrate during 1 h in the presence of 10 mM CaCl(2). The enzyme activity increased in the presence of Co(2+), Ba(2+), and Mn(2+). Using maltodextrin as substrate, the K(m) and K(cat) were 1.65 mg/mL and 347.9 micromol/mg x min, respectively.
In this work, a 3 3 factorial design was performed with the aim of optimizing the culture conditi... more In this work, a 3 3 factorial design was performed with the aim of optimizing the culture conditions for xylanase production by an alkalophilic thermophilic strain of Bacillus circulans , using response surface methodology. The variables involved in this study were xylan concentration (X 1 ), pH (X 2 ) and cultivation time (X 3 ). The optimal response region was approached without using paths of steepest ascent. Statistical analysis of results showed that, in the range studied, only pH did not have a significant effect on xylanase production. A second-order model was proposed to represent the enzymic activity as a function of xylan concentration (X 1 ) and cultivation time (X 3 ). The optimum xylan concentration and cultivation time were 5 g/l and 48 h, respectively. Under these conditions, the model predicted a xylanase activity of 19.1 U/ml.
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