Effects of glucose as carbon catabolite repressor on alpha-amylase and glucoamylase production in Indonesian indigenous fungi

Aims@#The study aimed to investigate the effect of glucose on alpha-amylase and glucoamylase production in some Indonesian indigenous fungi.@*Methodology and results@#Fungi were screened for their ability to produce alpha-amylase and glucoamylase in the presence of glucose. The strains were grown in a medium containing starch and glucose as carbon sources with glucose concentrations varying from 0 to 5% for four days, and the alpha-amylase and glucoamylase were analyzed at the end of the growth period. Most strains showed repression on the amylases production when glucose was added to the medium. However, some strains showed no repression on amylases production when glucose was supplemented to the medium. The addition of glucose repressed glucoamylase production, but no repression on alpha-amylase was noted for strain KKB4, vice versa, there was repression on alpha-amylase production but no repression on glucoamylase production for strain FIG1. Strains FNCC 6151 and MLT1J1 showed no repression on both alpha-amylase and glucoamylase production when glucose was added to the medium up to 5%. The occurrence of repression in the production of alpha-amylase and glucoamylase was strain-specific.@*Conclusion, significance and impact of study@#Out of the nine indigenous fungi strains examined, strains FNCC 6151 and MLT1J1 showed no repression on both alpha-amylase and glucoamylase production when glucose was added to the medium up to 5%. Those two strains have the potential to be improved further to produce both alpha-amylase and glucoamylase.

Health-promoting activities of edible seaweed extracts from Chilean coasts: assessment of antioxidant, anti-diabetic, anti-inflammatory and antimicrobial potential / Actividades promotoras de la salud de extractos de algas comestibles de las costas chilenas: evaluación del potencial antioxidante, antidiabético, antiinflamatorio y antimicrobiano

ABSTRACT The aim of this study was to evaluate the antioxidant, antidiabetic, anti-inflammatory and antimicrobial activities of three edible seaweed extracts from Chilean coasts: Pyropia orbicularis, Ulva spp, and Durvillaea antarctica. Seaweed extracts in methanol and 70% acetone were performed to evaluate antioxidant and antidiabetic activities, whereas 60% methanol was used to measure anti-inflammatory and antimicrobial activities. Acetone extracts from D. antarctica had the highest total phenolic content and consequently exhibited the strongest antioxidant activity, while methanol extract of this seaweed presented the highest α-glucosidase inhibition (IC50= 0.004 mg mL-1). In the tests against E. coli and Penicillium sp., the extracts obtained from Ulva spp. were the most effective and exhibited the maximum anti-inflammatory effect against phorbol 12-myristate 13-acetate irritant agent (61.8% inhibition) in mice. Results indicated that all evaluated Chilean seaweed extracts are promising candidates for application in functional foods and in the pharmaceutical industry.

RESUMEN El objetivo de este estudio fue evaluar las actividades antioxidantes, antidiabéticas, antiinflamatorias y antimicrobianas de los extractos de tres algas marinas comestibles de las costas Chilenas (Pyropia orbicularis, Ulva spp. y Durvillaea antarctica). Se realizaron extractos de algas marinas en metanol y acetona al 70% para evaluar las actividades antioxidantes y antidiabéticas, mientras que el metanol al 60% se usó para actividades antiinflamatorias y antimicrobianas. Los extractos de acetona de D. antarctica tuvieron el mayor contenido de fenoles totales (TPC) y, en consecuencia, exhibieron la mayor actividad antioxidante, mientras que el extracto metanólico de estas algas presentó la mayor inhibición de la α-glucosidasa (IC50= 0,004 mg mL-1). En las pruebas contra E. coli y Penicillium sp., los extractos obtenidos de Ulva spp., actuaron como los más efectivos y exhibieron el máximo efecto antiinflamatorio contra el agente irritante de forbol 12-miristato 13-acetato (TPA) (inhibición del 61,8%) en ratones. Por lo tanto, los resultados indican que todos los extractos de algas chilenas evaluados pueden ser candidatos prometedores para su aplicación en alimentos funcionales y en las industrias farmacéuticas.

Chemical characterization of the antioxidant, antihyperglycemic and antihypertensive capacities of red rice (Oryza sativa L. ) whole flour / Caracteristicas físico-químicas, capacidad antioxidante, anti-hiperlucémica y antihipertensiva de la harina de arroz rojo (Oryza sativa L. )

Oryza sativa L. rice has large amounts of proteins and minerals, besides presenting several pigmented varieties. Red rice is distinguishable due to its great nutritional value compared to the regular white variety. Its red pericarp pigmentation is due to the bioactive compounds that are responsible for its health benefits. The objective of this study was to evaluate the physical-chemical characterization, antioxidant, antihyperglycemic and antihypertensive capacity of flours of three different red rice cultures (Rubi, Virgínia and Pequeno). All samples presented specific levels of carbohydrates for cereals with low fat content and excellent levels of protein and resistant starch. In addition, the samples had a high antioxidant, antihyperglycemic and antihypertensive capacity. Antihyperglycemic capacities were measured as percent inhibition for amylase (56.7-76.5%) and glycosidase (81.0-76.6%), respectively, and antihypertensive capacity as the percentage inhibition of the angiotensin converting enzyme (38.4-34.7%). In addition, Pequeno flour presented the best results for antioxidant and antihyperglycemic capacity in comparison to the two flours tested. Thus, all red rice flours can be a source of functional compounds when added to food.

El arroz integral (Oryza sativa L.) posee importantes cantidades de proteínas, vitaminas, minerales y fitoquímicos. El arroz rojo se destaca por su gran valor nutricional. La pigmentación roja del pericarpio está asociado al contenido de compuestos bioactivos, que están directamente relacionados a los beneficios de salud humana. Teniendo en cuenta lo antes expuesto se propuso evaluar las caracteristicas físico-químicas, capacidad antioxidante, anti-hiperglucémica y antihipertensiva de las harinas de tres diferentes cultivos de arroz rojo (Rubí, Virginia y Pequeño). Todas las muestras presentaron niveles específicos de carbohidratos para cereales con bajo contenido de grasa y altos contenidos de proteína y almidón resistente. Además, las muestras presentaron una alta capacidad antioxidante, anti-hiperglucémica y antihipertensiva. La capacidad anti-hiperglicémica se midió en porcentaje de inhibidores de α-amilasa (56.7-76.5%) y α-glucosidasa (81.0-76.6%), respectivamente; y capacidad antihipertensiva como el porcentaje de inhibición de la enzima convertidora de la angiotensina (38.4-34.7%). El cultivar Pequeño presentó mayor capacidad antioxidante y anti-hiperglucémica en comparación a los demás cultivares. Así, todas las harinas de arroz rojo pueden ser vehículos de compuestos funcionales en los alimentos.

Production and characterization of a thermostable ß-glucosidase from Myceliophthora heterothallica / Produção e caracterização de uma ß-glicosidase termoestável de Myceliophthora heterothallica

The conversion of biomass from agro-industrial residues into bioproducts is of great interest, especially to Brazil, where bioenergy has a huge potential for development. Enzymes involved in biodegradation of lignocellulosic biomass are those of the cellulase system, of which ß-glucosidase is a constituent. The production and characterization of ß-glucosidase by the thermophilic fungus Myceliophthora heterothallica by solid-state cultivation on different agro-industrial residues (sugarcane bagasse, sugarcane straw, wheat bran and a mixture of these three materials (1:1:1 w/w) was evaluated. Solid-state cultivation were conducted in 250 mL Erlenmeyer flasks, with 5 g of each substrate. Different culture parameters, such as supplementary nutrient solution to the substrate, supplementary nutrient solution pH, initial substrate moisture and fungus incubation temperature, were evaluated to establish conditions of higher enzyme production by the fungus The greatest production of enzymes occurred in a mixture of wheat bran, sugarcane bagasse and straw bagasse (1:1:1). The activity of ß-glucosidase was greater under the following conditions: nutrient solution composed of NH4NO3, MgSO4.7H2O and (NH4)2SO4 (0.1%), at pH 4.5 or 6.0, fungus incubation at 40°C or 45°C, initial moisture of substrate at 80%. Enzyme presented optimum pH at pH 5.0 and good pH stability. Best temperature was 65°C and enzyme showed 100% stability for 1h, up to 60°C. The use of agro-industrial residues provided good production of ß-glucosidase by fungus, with enzyme having the characteristics desirable from the industrial application.

A conversão da biomassa vegetal proveniente de resíduos agroindustriais em bioprodutos é de grande interesse, principalmente para o Brasil, onde a agroenergia possui grande potencial de desenvolvimento. Enzimas envolvidas na biodegradação da biomassa lignocelulósica fazem parte do grupo das celulases, no qual a 훽-glucosidase é um constituinte. O presente estudo avaliou a produção e caracterização de uma ß-glicosidase pelo fungo termofílico Myceliophthora heterothallica por cultivo em estado sólido de diferentes resíduos agroindustriais (bagaço de cana-de-açúcar, palha de cana-de-açúcar, farelo de trigo e em uma mistura dos três materiais (1:1: 1 p/p). O cultivo em estado sólido foi realizado em frascos Erlenmeyer de 250 mL, contendo 5 g de cada substrato. Diferentes parâmetros de cultivo, como solução nutriente suplementar ao substrato, pH da solução nutriente suplementar, umidade inicial do substrato e temperatura de incubação do fungo foram avaliados, visando estabelecer condições para maior produção da enzima pelo fungo. A maior produção da enzima ocorreu na mistura de farelo de trigo, e bagaço e palha de cana-de-açúcar (1:1:1). A atividade da ß-glicosidase foi maior nas seguintes condições: solução nutriente composta por NH4NO3, MgSO4.7H2O e (NH4)2SO4 (0,1%) com pH 4,5 e 6,0, temperatura de incubação do fungo a 40°C e 45°C, com umidade inicial do substrato em 80%. A enzima apresentou pH ótimo de 5,0, e boa estabilidade ao pH. A temperatura ótima foi de 65°C, e a enzima apresentou 100% de estabilidade por 1h, até 60°C. A utilização de resíduos agroindustriais proporcionou boa produção de ß-glicosidase pelo fungo, com a enzima apresentando características desejáveis para aplicação industrial.

Independent and synergistic activity of the flavonoids of Gracilaria corticata as promising antidiabetic agents

The therapeutic approaches for Type 2 Diabetes Mellitus rely most on the usage of oral hypoglycaemic drugs. These drugs have adverse side effects and hence alternative medicines are continuously explored. The present study intends to investigate the antidiabetic potential of the flavonoids present in Gracilaria corticata. The flavonoids were isolated (FEGC) and their inhibitory activity on the carbohydrate hydrolysing enzymes such as α-amylase and α-glucosidase was analysed. The flavonoids were found to inhibit α-amylase and α-glucosidase with an IC50 value of 302 µg and 75 µg respectively. The synergistic effect of FEGC and luteolin was also investigated and the results show that both FEGC and luteolin inhibited synergistically at half their IC50 values. The observations of this study reveal that the flavonoids of G. corticata have potential antidiabetic activity and can act independently or synergistically in the management of Type 2 Diabetes Mellitus

Enhanced production of ß- glucosidase by locally isolated fungal strain employing submerged fermentation / Aumento da produção de ß-glucosidase por estirpe fúngica isolada localmente, por fermentação submersa

ß-glucosidase has wide spectrum of biotechnological applications in different industries including food, textile, laundry detergents, pulp and paper, pharmaceutical and biofuel industry. The present investigation related to isolation, screening, and process optimization of fungal strain for enhanced production of ß-glucosidase (BGL). For this purpose, different fungal stains were isolated from different sources including soil, fruits, bark of tree as well as from the compost. The screening of fungal strain for BGL production was carried out via submerged fermentation. All the tested strains were identified on the basis of micro and macroscopic features. The fungal strain having greater ability for BGL synthesis among tested ones wasidentified as Aspergillus niger and given the code SBT-15. The process parameter including fermentation media, temperature, pH, rate of fermentation, carbon and nitrogen sources, volume of media were optimized. Five different fermentation media were evaluatedM3medium gave maximum production. The optimal conditions for BGL production was 72 hours of incubation at 40°C, pH 6 and 50 ml fermentation medium. Glucose (1%) and ammonium sulphate(3%) were optimized as best carbon and nitrogen sources, respectively.

A ß-glicosidase possui amplo espectro de aplicações biotecnológicas em diferentes indústrias, incluindo alimentos, têxteis, detergentes para lavanderia, papel e celulose, indústria farmacêutica e de biocombustíveis, etc. A presente investigação relaciona-se ao isolamento e triagem e otimização de processos de cepas fúngicas para produção aumentada de ß- glucosidase (BGL). Para este efeito, diferentes manchas fúngicas foram isoladas a partir de diferentes fontes, incluindo solo, frutos, casca de árvore, bem como a partir do composto. A triagem da linhagem fúngica para produção de BGL foi realizada via fermentaçãosubmersa. Todas as cepas testadas foram identificadas com base em características micro e macroscópicas. A linhagem fúngica com maior capacidade de síntese de BGL entre os testados foi identificada como Aspergillus niger e recebeu o código SBT-15. O parâmetro do processo, incluindo meios de fermentação, temperatura, pH, taxa de fermentação, fontes de carbono e nitrogênio, volume de mídia foram otimizados. Cinco meios de fermentação diferentes foram avaliados. O meio M3 deu a produção máxima. As condições ótimas para a produção de BGL foram 72 horas de incubação a 40 ° C, pH 6 e 50ml de meio de fermentação. Glicose (1%) e sulfato de amônio (3%) foram otimizados como melhores fontes de carbono e nitrogênio, respectivamente.

Highly efficient enzymatic preparation of isomalto-oligosaccharides from starch using an enzyme cocktail

Background: Current commercial production of isomalto-oligosaccharides (IMOs) commonly involves a lengthy multistage process with low yields. Results: To improve the process efficiency for production of IMOs, we developed a simple and efficient method by using enzyme cocktails composed of the recombinant Bacillus naganoensis pullulanase produced by Bacillus licheniformis, α-amylase from Bacillus amyloliquefaciens, barley bran ß-amylase, and α-transglucosidase from Aspergillus niger to perform simultaneous saccharification and transglycosylation to process the liquefied starch. After 13 h of reacting time, 49.09% IMOs (calculated from the total amount of isomaltose, isomaltotriose, and panose) were produced. Conclusions: Our method of using an enzyme cocktail for the efficient production of IMOs offers an attractive alternative to the process presently in use.

Leojaponic acids A and B, two new homologous terpenoids, isolated from Leonurus japonicus / 中国天然药物

The present study aimed at isolation and purification of the bioactive terpenoids from the herb of Leonurus japonicus by chromatographic separations such as silica gel, sephadex LH-20 and C18 reversed phase silica gel, as well as preparative HPLC. As a result, leojaponic acids A (1, C17H24O4) and B (2, C18H26O4), two homologous terpenoids, together with (-)-loliolide (3), 1-(3-ethylphenyl) ethane-1, 2-diol (4) and dibutyl phthalate (5), were isolated from the EtOH extract of L. japonicus. All the chemical structures of the isolates were elucidated on the basis of 1D and 2D NMR analyses. Compounds 1 and 2 were new terpenoids, and Compounds 3 and 4 were isolated and identified for the first time from this plant. In addition, the α-glucosidase and tyrosinase inhibitory activity of the new compounds were evaluated.

Determination of alpha-glucosidase inhibitory activity from selected Fabaceae plants

Nineteen plants from Fabaceae family, which were used in Thai traditional medicine for treatment of diabetes, were determined of alpha-glucosidase inhibitory activity via enzymatic reaction. In this reaction, alpha-glucosidase was used as enzyme, which, reacted with the substrate, Rho-nitrophenol-D-glucopyranoside [pNPG]. After that the product, p-nitro phenol [pNP] will be occurred and observed the yellow colour at 405 nm. In this study, acarbose was used as positive standard which, inhibited this enzyme with IC[50] as 331 +/- 4.73 microg/ml. Caesalpiniapulcherrima leaves showed the highest activity with IC[50] as 436.97 +/- 9.44 microg/ml. Furthermore, Bauhinia malabarica leaves presented moderately activity with IC[50] as 745.08 +/- 11.15 microg/ml. However, the other plants showed mild to none activity of alpha-glucosidase inhibition. Accordingly, this study can support anti-diabetes of these plants in traditional medicine and it will be the database of the biological activity of Fabaceae plant

Determinación cuantitativa de enterococos en aguas utilizando un método cromogénico alternativo / Quantitative determination of enterococci in water using an alternative chromogenic method

INTRODUCCIÓN: el control de la calidad de las aguas es vital para la protección de la salud humana y la biodiversidad en el ambiente acuático. Varios microorganismos son utilizados como indicadores de contaminación fecal para este propósito, dentro de ellos los enterococos son considerados buenos indicadores, porque sobreviven más tiempo ante condiciones adversas en la naturaleza. OBJETIVOS: evaluar la capacidad de un nuevo método cromogénico alternativo para la detección y enumeración de enterococos en aguas por la técnica de filtración por membrana, en comparación con el método estándar ISO 7899:2. MÉTODOS: se recolectaron muestras de aguas de tres orígenes diferentes para determinar su calidad. Las muestras se ensayaron en paralelo por las dos metodologías (alternativa y referencia), empleando la técnica de filtración por membrana. Para evaluar el desempeño de los métodos se determinaron varios parámetros: sensibilidad, especificidad, exactitud, porcentaje de falsos positivos, porcentaje de falsos negativos, índice kappa. Los tres primeros parámetros se calcularon para ambos métodos antes y después de la confirmación por pruebas bioquímicas. Los resultados se analizaron desde el punto de vista estadístico, teniendo en cuenta los principales criterios definidos en las normas ISO 16140 e ISO 177994. RESULTADOS: con el método alternativo los resultados se obtuvieron a las 24 h, estos mostraron valores de sensibilidad (99 %) y exactitud (98 %) más elevados que con el de referencia (97 % y 97 %, respectivamente), el cual demoró más de 48 h. La eficiencia y exactitud de ambos métodos fue similar y se obtuvo una concordancia entre ellos casi perfecta (kappa = 0,96) con el total de las muestras de aguas ensayadas. CONCLUSIONES: los resultados alcanzados indican que el método alternativo es eficiente para el recuento de enterococos provenientes de diferentes tipos de muestras de agua. Resulta además un método simple, más rápido y económicamente factible.

INTRODUCTION: water quality control is essential for the protection of human health and biodiversity in the aquatic environment. For this purpose, several microorganisms are used as indicators of fecal contamination. Among them are enterococci, which are considered to be good indicators, since they survive for a longer time in adverse natural conditions. OBJECTIVES: evaluate the suitability of a new alternative chromogenic method for the detection and enumeration of enterococci in water by membrane filtration technique, in comparison with the ISO 7899:2 standard method. METHODS: water samples were collected from three different sources to determine their quality. The samples were assayed in parallel with the two methodologies (alternative and reference) using the membrane filtration technique. The following parameters were determined to evaluate the performance of the methods: sensitivity, specificity, accuracy, percentage of false positives, percentage of false negatives, kappa index. The first three parameters were estimated for both methods before and after confirmation by biochemical testing. Results were analyzed statistically based on the main criteria defined by ISO standards 16140 and 177994. RESULTS: with the alternative method, results were obtained at 24 h, whereas the reference method required more than 48 h. Sensitivity and accuracy were higher with the alternative method (99 % and 98 %, respectively) than with the reference method (97% and 97%, respectively). Both methods had similar efficiency and accuracy, with almost perfect concordance between them (kappa = 0.96) in all the water samples tested. CONCLUSIONS: results show that the alternative method is efficient for the enumeration of enterococci from different types of water samples. It is also a simple, faster and economically feasible method.

Display cellulolytic enzymes on Saccharomyces cerevisiae cell surface by using Flo1p as an anchor protein for cellulosic ethanol production / 生物工程学报

In this study, we constructed a yeast consortium surface-display expression system by using Flo1 as an anchor protein. Endoglucanase II (EGII) and cellobiohydrolase II (CBHII) from Trichoderma reesei, and β3-glucosidase 1 (BGLI) from Aspergillus aculeatus were immobilized on Saccharomyces cerevisiae Y5. We constructed the cellulose-displaying expression yeast consortium (Y5/fEGII:Y5/fCBHII:Y5/fBGLI = 1:1:1) and investigated the enzymatic ability and ethanol fermentation. The displayed cellulolytic enzymes was stabile during the 96-h fermentation. The yeast consortium produced 0.77 g/L ethanol from 10 g/L phosphoric acid swollen cellulose (PASC) within 96 h. The yield (in grams of ethanol produced per gram of carbohydrate consumed) was 0.35 g/g, which correspond to 68.6% of the theoretical yield.

Sugarcane bagasse as feedstock for cellulase production by Trichoderma harzianum in optimized culture medium

This work aimed at the production of cellulases from pretreated sugarcane bagasse by the filamentous fungus Trichoderma harzianum IOC 3844 and their application in the hydrolysis of this same substrate, for a future use in second-generation ethanol production. The production of cellulases was optimized, which resulted in high enzymatic activities after 42 hrs of process in an instrumented bioreactor (CMCase 27,017 U x L-1; FPase 1,225 U x L-1; and β-glucosidase 609 U x L-1). The enzymatic extract was concentrated by using a hollow fiber membrane filtration system. The concentrated extract was applied in the hydrolysis of pretreated sugarcane bagasse, after 28 hrs of enzymatic reaction, displaying a similar catalytic performance of that attained with a commercial enzymatic preparation (hydrolysis efficiency of roughly 50%). Finally, the enzymatic extract was partially characterized in terms of the molecular weights of the main activities of the enzymatic pool. Electrophoretic analysis identified eleven protein bands; six of them were related to CMCase activity and revealing molecular weights that varied from 48 to 78 kDa, and two bands were associated with β-glucosidase activity and having molecular weights of 75 and 85 kDa.

A method to determine the structure of the complex of enzyme and its substrate using 6-phosphate-beta-glucosidase at low temperature / 生物工程学报

To capture a state of the enzyme in complex with an intact substrate, we developed and adopted a novel freezing method in crystal preparation procedure. Neither the elimination of the catalytically indispensable ligands, nor mutation or modification of the active site is required. At -20 degrees C, we soaked the crystal of 6-phosphate-beta-glucosidase (Bg1A) in the liquor containing p-nitrophenyl-beta-D-glucopyranoside-6-phosphate (pNPbetaG6P). The diffraction data at 2 A resolution was collected and an intact and unambiguous electron density map of pNPbetaG6P was obtained. These results provide an effective method for the research of cryoenzymology and the intermediate state of enzyme-substrate complex in the future.

Effect of laurus nobilis L. essential oil and its main components on alpha-glucosidase and reactive oxygen species scavenging activity

The present study was designed to determine the effects of the essential oil of Laurus nobilis L. [Lauraceae] and its three main components on alpha-glucosidase and reactive oxygen species scavenging activity. The chemical composition of the essential oil from Laurus nobilis L. leaves was analyzed by GC/GC-MS and resulted in the identification of 29 compounds, representing 99.18% of the total oil. 1,8-cineole [68.82%], 1-[S]-alpha-pinene [6.94%], and R-[+]-limonene [3.04%] were determined to be the main components. The antioxidant features of the essential oil and its three main components were evaluated using inhibition of 2,2-diphenyl-1-picrylhydrazyl, hydroxyl, and superoxide radicals, inhibition of hydrogen peroxide and lipid peroxidation assays. The results show that the DPPH, hydroxyl, and superoxide radical as well as hydrogen peroxide scavenging activities of the essential oil are greater than the positive controls and the three main components of the oil when tested independently. The inhibition of lipid peroxidation by the oil occurred less frequently than with 1,8-cineole and R-[+]-limonene alone, but the effects were more pronounced than those seen with 1-[S]-alpha-pinene and the positive controls. An alpha-glucosidase inhibition assay was applied to evaluate the in-vitro antidiabetic activity of the essential oil. IC[50]-values were obtained for laurel essential oil, 1, 8-cineole, 1-[S]-alpha-pinene, and R-[+]-limonene: 1.748 micro L/mL, 1.118 micro L/mL, 1.420 micro L/mL and 1.300 micro L/mL, respectively. We also found that laurel essential oil and 1, 8-cineole inhibited the alpha-glucosidase competitively while 1-[S]-alpha-pinene and R-[+]-limonene were uncompetitive inhibitors

Pharmacotherapy for Postprandial Hyperglycemia in Type 2 Diabetes / 임상당뇨병

A growing body of evidence shows that effective postprandial hyperglycemia management in individuals with type 2 diabetes can reduce the risk of diabetic complications and cardiovascular diseases. Therefore, accurate monitoring and effective intervention for postprandial hyperglycemia is very important in routine clinical practice for type 2 diabetes. Therapeutic modalities for the management of postprandial hyperglycemia include oral antidiabetic drugs (alpha glucosidase inhibitor, meglitinide, dipeptidyl peptidase-IV inhibitor), ultra-short-acting insulin analogues, and incretin mimetics. A detailed understanding of the advantages and disadvantages of various pharmacotherapies and a careful understanding of the underlying physical and social situations of each patient will be of great help to determine the appropriate prescription for postprandial hyperglycemia management.

Hydrolytic potential of a psychrotrophic Pseudomonas isolated from refrigerated raw milk

The production of extracellular hydrolases by a psychrotrophic bacterium isolated from refrigerated raw milk, and identified as a Pseudomonas sp. belonging to the Pseudomonas jenssenii group, was studied. This bacterium produced proteolytic and lipolytic enzymes in all media investigated (skim milk, cheese whey, casein broth, and tryptone soy broth). High levels of á-glucosidase were produced in skim milk broth. Hydrolytic enzymes detected in skim milk broth are of particular concern, indicating that these enzymes could be produced by Pseudomonas sp. during the cold storage of raw milk, contributing to the spoilage problem in milk and dairy products.

Produccion de beta-glucosidasas por cultivos de bacterias termofilas indigenas del altiplano boliviano / beta-Glucoside production by thermophilic bacteria indigenous the bolivian altiplano culture

Las beta-glucosidasas son enzimas que poseen actividad hidrolitica y transferasa o transglucosidasa. Tienen diversas aplicaciones; en la biosintesis de oligosacaridos, produccion de etanol utilizando residuos agricolas y en la industria de vinos. La aplicacion industrial, sin embargo, requiere estabilidad a temperaturas elevadas, por lo que los microorganismos termofilos tienen gran interes. El proposito de esta investigacion es el de optimizar el medio de cultivo anaerobio de bacterias termofilas, para aumentar la produccion de beta-glucosidasas. Esta enzima es producida por tres aislados bacterianos: FT3, 2B y P5 los cuales fueron aislados de la region andina de Bolivia. El aislado bacteriano FT3 mostro una actividad beta-glucosidasa de 0,35 [UI/mL]. Se tomaron como variables dentro de la optimizacion del medio de cultivo las fuentes de nitrogeno y de carbono, y el pH. Asi tambien se probaron dos sistemas de cultivo: celulas libres y encapsuladas. Empleando extracto de levadura como fuente de nitrogeno se obtuvo una actividad de 0,52 [UI/mL]. En la optimizacion del pH del medio de cultivo se obtuvo una actividad de 0,81 [UI/mL] a pH 5. Como fuente de carbono se eligieron los hidrolizados de paja de trigo y paja de quinoa lleg¨¢ndose a obtener actividades de 1,27 y 1,34 [UI/mL] respectivamente. Se establecio que la localizacion celular de la enzima beta-glucosidasa es extracelular y presenta estabilidad hasta una temperatura de 80 ºC y un pH de 7.

The beta-glucosidases possess hydrolytic and transferase activity or transglucosidase. They have various applications; such as biosynthesis of oligosaccharides, production of ethanol using agricultural residues and wine industry. However for industrial application, stability to high temperatures is needed. Therefore a great interesting in the thermophile microorganism study exist. The purpose of this research is to optimize the culture medium of thermophilic anaerobic bacteria to increase the production of beta-glucosidase. This enzyme is produced by three isolate bacterial FT3, 2B and P5 which were isolated from the Andean region of Bolivia. FT3 isolate showed beta-glucosidase activity of 0.35 [IU/mL]. In regards to the optimization of culture medium variables such as nitrogen source, carbon source and pH were taken into account and also the combination with free and encapsulated bacterial cells. Yeast extract was the selected source of nitrogen obtaining an activity of 0.52 [IU/ mL]. The optimal pH was 5 obtaining an activity of 0.81 [IU/mL]. The selected carbon source was the hydrolyzed wheat straw and quinoa straw obtaining activities of 1.27 and 1.34 [IU/mL], respectively. The cellular localization of beta-glucosidase enzyme is extracellular and provides stability to temperature of 80 ºC and stability at pH 7.

Enhancing ethanol production using thermophilic yeast by response surface methodology / 生物工程学报

We optimized the conditions of simultaneous saccharification and fermentation (SSF) from cassava flour into high-concentration ethanol by thermophilic yeast GXASY-10. Based on the single factor experiment, we screened the important parameters by Plackeet-burman design. We used the path of steepest ascent to approach to the biggest region of ethanol production subsequently. Then, we obtained the optimum values of the parameters by Box-Behnken design. The results showed that the important parameters were the liquefaction time, glucosidase dosages and initial concentration of cassava flour (substrate). The optimum technical conditions were as follows: liquefaction time 35 min, glucosidase dosages 1.21 AGU/g substrate and initial substrate concentration 37.62%. Under such optimum conditions, the ethanol yield of 20 L fermentor reached 16.07% (V/W) after 48 h fermentation at 37 degrees C and 100 r/min. The ethanol content increased 33% than that under the original condition.

Kinetics of high-level of ß-glucosidase production by a 2-deoxyglucose-resistant mutant of Humicola lanuginosa in submerged fermentation / Cinética de produção de ß-glucosidase por um mutante de Hemicola lanuginosa resistente a 2-deoxiglucose em fermentação submersa

A 2-deoxyglucose-resistant mutant (M7) of Humicola lanuginosa was obtained by exposing conidia to γ-rays and permitting expression in broth containing 0.6 percent 2-deoxyglucose (DG) and cellobiose (1 percent) before plating on DG esculin-ferric ammonium citrate agar medium from which colonies showing faster and bigger blackening zones were selected. Kinetic parameters for enhanced ß-glucosidase (BGL) synthesis by M7 were achieved when corncobs acted as the carbon source. The combination between corncobs and corn steep liquor was the best to support higher values of all product formation kinetic parameters. Effect of temperature on the kinetic and thermodynamic attributes of BGL production equilibrium in the wild organismand M7was studied using batch process at eight different temperatures in shake-flask studies. The best performance was found at 45ºC and 20 g L-1 corncobs in 64 h. Both growth and product formation (17.93 U mL-1) were remarkably high at 45ºC and both were coupled under optimum working conditions. Product yield of BGL from the mutant M7 (1556.5 U g-1 dry corncobs) was significantly higher than the values reported on all fungal and bacterial systems. Mutation had thermo-stabilization influence on the organism and mutant required lower activation energy for growth and lower magnitudes of enthalpy and entropy for product formation than those demanded by the wild organism, other mesophilic and thermo-tolerant organisms. In the inactivation phase, the organisms needed lower values of activation energy, enthalpy and entropy for product formation equilibrium, confirming thermophilic nature of metabolic network possessed by the mutant organism.

Um mutante de Hemicola lanuginosa resistente a 2-deoxiglucose(M7) foi obtido através de exposição de conídios a raios γ, permitindo a expressão em caldo contendo 0,6 por cento de 2-deoxiglucose (DG) e celobiose (1 por cento) antes da semeadura em ágar DG esculina citrato de ferro amoniacal, da qual foram selecionadas as colônias com halo negro. Os parâmetros cinéticos para produção aumentada de ß-glucosidase (BGL) foram obtidos empregando-se sabugo de milho como fonte de carbono. A combinação de espiga de milho com água de maceração de milho foi a que forneceu os valores mais altos nos parâmetros cinéticos de formação de todos os produtos. O efeito da temperatura na cinética e atributos termodinâmicos da produção de BGL pelas cepas selvagem e M7 foi avaliado empregando-se processo de batelada em oito temperaturas diferentes in frascos em agitação. O melhor desempenho foi observado a 45ºC e 20g.l-1 de espiga de milho em 64h. Tanto a multiplicação quanto a formação do produto foram muito altas a 45ºC e ambas estavam ligadas em condições ótimas de trabalho. O rendimento de BGL produzido pelo mutante M7 (1556 U.g-1 de espiga seca) foi significativamente superior aos valores reportados para todos os sistemas fúngicos e bacterianos. A mutação influenciou a termoestabilização no microrganismo, sendo que o mutante necessitou de energia de ativação mais baixa para multiplicação e valores mais baixos de entalpia e entropia para a formação do produto quando comparado à cepa selvagem e a outros microrganismos mesofilicos e termotolerantes. Na fase de inativação, os microrganismos necessitaram valores mais baixos de energia de ativação, entalpia e entropia para o equilíbrio da formação de produto, confirmando a natureza termofílica da máquina metabólica do mutante.