87 research outputs found

    Response surface methodological approach to optimize the nutritional parameters for enhanced production of -amylase in solid state fermentation by Thermomyces lanuginosus

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    Response surface methodology was used to study the cumulative effect of the nutritional parameters and to enhance the production of extracellular -amylase in solid-state ermentation by Thermomyces lanuginosus ATCC 58157. These nutritional parameters considered include carbon source (soluble starch), nitrogen source (peptone) and a concentrated mineral medium. For obtaining the mutual interaction between the variables and optimizing these variables, a 23 factorial central composite design using response surface methodology was employed. The optimal calculated values of tested variables for maximal production of -amylase were: soluble starch, 71.10 g/Kg peptone, 91.97 g/Kg and mineral salts solution, 175.05 ml/Kg with a predicted -amylas activity of 5.085 ´ 105 U/Kg of wheat bran. These predicted optimal parameters were tested in the laboratory and the final -amylase activity obtained, 4.94 ´ 105 U/Kg of wheat bran, was very close to the predicted value.African Journal of Biotechnology Vol. 4 (7), pp. 708-716, 200

    Degradation of pulp and paper-mill effluent by thermophilic micro-organisms using batch systems

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    Paper manufacturers produce large quantities of wastewater, which can have deleterious effects on the receiving waters; therefore there is a need to find a treatment process which can minimize these effects considerably. A suitable aerobic biological treatment process that can be used with great success involves the use of thermophilic micro-organisms. This technology has many advantages, which include rapid biodegradation rates, low sludge yields, and excellent process stability. Batch studies were conducted on two types of activated sludge (pulp-mill sludge and sewage sludge) at 40°C, 50°C and 60°C to determine the feasibility of thermophilic degradation of bleach pulp-mill effluent in terms of increasing aeration, biomass concentration and nutrient addition. Preliminary batch studies had confirmed the feasibility of thermophilic degradation, as COD removal achieved with the pulp-mill sludge was 55.2%, 37.6% and 31.4% at 40°C, 50°C and 60°C after 5d, respectively while the COD removal with sewage sludge was 50.2%, 37.3% and 27% under the same conditions. Degradation was further improved, using the same inocula in subsequent experiments and this confirmed that an acclimatization period is required, prior to degrading the bleach pulp-mill effluent. Thermophilic degradation of pulp-mill effluent occurs at temperatures of up to 60°C; however, once final degradation is obtained, it decreases significantly as temperature increases. Keywords: thermophilic micro-organisms, pulp and paper mill effluent, degradation, batch systems Water SA Vol. 31(4) 2005: 575-58

    Pročišćavanje i karakterizacija endoinulinaze iz mutanta bakterije Xanthomonas campestris pv. phaseoli KM 24

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    An extracellular endoinulinase from Xanthomonas campestris pv. phaseoli KM 24 mutant was purifi ed to homogeneity by gel fi ltration chromatography and showed a specifi c activity of 119 U/mg. The optimum pH and temperature of the purifi ed enzyme were found to be 6.0 and 50 °C, respectively. The enzyme was stable up to 60 °C, retaining 60 % of residual activity for 30 min, but inactivated rapidly above 60 °C. The enzyme was found to be stable at pH=6–9 when it retained 100 % of its residual activity. The Lineweaver-Burk plot showed that the apparent Km and vmax values of the inulinase when using inulin as a substrate were 1.15 mg/mL and 0.15 μM/min, respectively, whereas the kcat value was found to be 0.145 min–1. The calculated catalytic effi ciency of the enzyme was found to be 0.126 (mg·min)/mL. The purifi ed inulinase can be used in the production of high fructose syrups.Iz mutanta bakterije Xanthomonas campestris pv. phaseoli KM 24 izolirana je izvanstanična endoinulinaza, te je pročišćena gel-filtracijskom kromatografijom. Specifična aktivnost bila je 119 U/mg. Optimalna pH-vrijednost za aktivnost pročišćenog enzima bila je 6,0 a temperatura 50 °C. Enzim je bio stabilan na temperaturama manjim od 60 °C, zadržavajući 60 % aktivnosti tijekom 30 min, ali se iznad 60 °C naglo inaktivirao. Pri pH- -vrijednosti od 6 do 9 enzim je zadržao 100 % aktivnosti. Pomoću Lineweaver-Burk-ovog dijagrama utvrđeno je da je na podlozi s inulinom Km vrijednost inulinaze bila 1,15 mg/mL a vmax 0,15 μg/mL, dok je kcat vrijednost iznosila 0,145 min-1. Katalitička je aktivnost enzima bila 0,126 (mg·min)/mL. Zaključeno je da se pročišćena se inulinaza može primijeniti za proizvodnju sirupa s velikim udjelom fruktoze

    The association between indices of obesity and common clinical measures in adults with and without type 2 diabetes

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    Background: The aim of this study was to determine the differences amongst the anthropometric measurements, lipid profile, blood pressure and body shape in diabetics as well as non-diabetics.Methods: This was a cross-sectional study comprised of 309 subjects with 91 males and 218 females. Of this, there were 217 diabetics and 92 non-diabetics. The sample was taken from three hospitals in Trinidad. Lipid profile and blood pressure were taken from each facility’s physician’s notes while anthropometric measurements were taken from the patients themselves.Results: The diabetic group had elevated body mass index and waist to hip ratios were significant (P <0.05) when compared to non-diabetics. There was no significant association of lipid profile, blood pressure, waist circumference and waist to height ratios between diabetics and non-diabetics. As age increased, the prevalence of type 2 diabetes mellitus was more common. Out of 217 diabetics, 173 were of East Indian descent. With regards to gender, more males were found to be diabetics resulting from having an android body shape as compared to females (gynoid body shape).Conclusion: It was found that of all the anthropometric measurements used, waist to hip ratio was found to be the most effective indicator of type 2 diabetes mellitus in Trinidadians, while body mass index was found to be the least effective indicator.

    Isolation and screening of microorganisms from a gari fermentation process for starter culture development

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    Cassava (Manihot esculenta Crantz), is used for the production of a variety of West African foods and ranks fourth in the list of major crops in developing countries after rice, wheat and maize. Gari is one of the most popular foods produced from cassava. Cassava may contain high levels of linamarin, a cyanogenic glucoside, which in its natural state is toxic to man. Therefore, some processing methods that can enhance the  detoxification of cassava and lead to the improvement of the quality and hygienic safety of the food are vitally important for less toxic products to be obtained. Quality, safety and acceptability of traditional fermented  foods may be improved through the use of starter cultures. There has been a trend recently to isolate wild-type strains from traditional products for use as starter cultures in food fermentation. A total of 74 bacterial strains and 21 yeast strains were isolated from a cassava mash fermentation process in a rural village in Benin, West Africa. These strains were assessed, together with 26 strains isolated at the Council for Scientific and  Industrial Research (CSIR) from cassava samples sent from Benin previously, for phenotypic and  technological properties. 24 presumptive lactic acid bacteria (LAB) were selected for further phenotypic,  genotypic and technological characterization.Key words: Lactic acid bacteria, gari, cassava, fermentation

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

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    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 , \u3b1-amylase from Bacillus amyloliquefaciens , barley bran \u3b2-amylase, and \u3b1-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

    Incremental value of left ventricular global longitudinal strain in moderate aortic stenosis and reduced left ventricular ejection fraction

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    BACKGROUNDModerate aortic stenosis (AS) often coexists with left ventricular (LV) systolic dysfunction and may affect survival through afterload mismatch. Because outcomes are ultimately driven by the condition of the LV, accurate assessment of LV performance is crucial to improve risk stratification. This study investigated the prognostic value of LV global longitudinal strain (GLS) in patients with moderate AS and reduced LV systolic dysfunction.METHODSPatients with moderate AS (aortic valve area 1.0-1.5 cm2) and reduced LV ejection fraction (EF) (RESULTSA total of 166 patients (mean age 73 ± 11 years, 71% male) were included. The cumulative 1- and 5-year mortality rates were higher in patients with LVGLS CONCLUSIONThe combination of moderate AS and reduced LV systolic dysfunction is associated with a high mortality risk. LVGLS, but not LVEF, is independently associated with mortality and provides incremental prognostic value over established risk factors in patients with moderate AS and reduced LVEF.</p

    Tight Junction Proteins and Signaling Pathways in Cancer and Inflammation: A Functional Crosstalk.

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    The ability of epithelial cells to organize through cell-cell adhesion into a functioning epithelium serves the purpose of a tight epithelial protective barrier. Contacts between adjacent cells are made up of tight junctions (TJ), adherens junctions (AJ), and desmosomes with unique cellular functions and a complex molecular composition. These proteins mediate firm mechanical stability, serves as a gatekeeper for the paracellular pathway, and helps in preserving tissue homeostasis. TJ proteins are involved in maintaining cell polarity, in establishing organ-specific apical domains and also in recruiting signaling proteins involved in the regulation of various important cellular functions including proliferation, differentiation, and migration. As a vital component of the epithelial barrier, TJs are under a constant threat from proinflammatory mediators, pathogenic viruses and bacteria, aiding inflammation and the development of disease. Inflammatory bowel disease (IBD) patients reveal loss of TJ barrier function, increased levels of proinflammatory cytokines, and immune dysregulation; yet, the relationship between these events is partly understood. Although TJ barrier defects are inadequate to cause experimental IBD, mucosal immune activation is changed in response to augmented epithelial permeability. Thus, the current studies suggest that altered barrier function may predispose or increase disease progression and therapies targeted to specifically restore the barrier function may provide a substitute or supplement to immunologic-based therapies. This review provides a brief introduction about the TJs, AJs, structure and function of TJ proteins. The link between TJ proteins and key signaling pathways in cell proliferation, transformation, and metastasis is discussed thoroughly. We also discuss the compromised intestinal TJ integrity under inflammatory conditions, and the signaling mechanisms involved that bridge inflammation and cancer
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