Glucose Recovery from Different Corn Stover Fractions Using Dilute Acid and Alkaline Pretreatment Techniques

Background: Limited availability of corn stover due to the competing uses (organic manure, animal feed, bio-materials, and bioenergy) presents a major concern for its future in the bio-economy. Furthermore, biomass research has exhibited different results due to the differences in the supply of enzymes and dissimilar analytical methods. The effect of the two leading pretreatment techniques (dilute acid and alkaline) on glucose yield from three corn stover fractions (cob, stalk, and leaf) sourced from a single harvest in Uganda were studied at temperatures 100, 120, 140, and 160 °C over reaction times of 5, 10, 30, and 60 min. Results: From this study, the highest glucose concentrations obtained from the dilute acid (DA) pretreated cobs, stalks, and leaves were 18.4 g/L (66.8% glucose yield), 16.2 g/L (64.1% glucose yield), and 11.0 g/L (49.5% glucose yield), respectively. The optimal pretreatment settings needed to obtain these yields from the DA pretreated samples were at a temperature of 160 °C over an incubation time of 30 min. The highest glucose concentrations obtained from the alkaline (AL) pretreated cobs, stalks, and leaves were 24.7 g/L (81.73% glucose yield), 21.3 g/L (81.23% glucose yield), and 15.0 g/L (51.92% glucose yield), respectively. To be able to achieve these yields, the optimal pretreatment settings for the cobs and stalks were 140 °C and for a retention time of 30 min, while the leaves require optimal conditions of 140 °C and for a retention time of 60 min. Conclusions: The study recommends that the leaves could be left on the field during harvesting since the recovery of glucose from the pretreated cobs and stalks is higher

Role of age and comorbidities in mortality of patients with infective endocarditis

[Purpose]: The aim of this study was to analyse the characteristics of patients with IE in three groups of age and to assess the ability of age and the Charlson Comorbidity Index (CCI) to predict mortality. [Methods]: Prospective cohort study of all patients with IE included in the GAMES Spanish database between 2008 and 2015.Patients were stratified into three age groups:<65 years,65 to 80 years,and ≥ 80 years.The area under the receiver-operating characteristic (AUROC) curve was calculated to quantify the diagnostic accuracy of the CCI to predict mortality risk. [Results]: A total of 3120 patients with IE (1327 < 65 years;1291 65-80 years;502 ≥ 80 years) were enrolled.Fever and heart failure were the most common presentations of IE, with no differences among age groups.Patients ≥80 years who underwent surgery were significantly lower compared with other age groups (14.3%,65 years; 20.5%,65-79 years; 31.3%,≥80 years). In-hospital mortality was lower in the <65-year group (20.3%,<65 years;30.1%,65-79 years;34.7%,≥80 years;p < 0.001) as well as 1-year mortality (3.2%, <65 years; 5.5%, 65-80 years;7.6%,≥80 years; p = 0.003).Independent predictors of mortality were age ≥ 80 years (hazard ratio [HR]:2.78;95% confidence interval [CI]:2.32–3.34), CCI ≥ 3 (HR:1.62; 95% CI:1.39–1.88),and non-performed surgery (HR:1.64;95% CI:11.16–1.58).When the three age groups were compared,the AUROC curve for CCI was significantly larger for patients aged <65 years(p < 0.001) for both in-hospital and 1-year mortality. [Conclusion]: There were no differences in the clinical presentation of IE between the groups. Age ≥ 80 years, high comorbidity (measured by CCI),and non-performance of surgery were independent predictors of mortality in patients with IE.CCI could help to identify those patients with IE and surgical indication who present a lower risk of in-hospital and 1-year mortality after surgery, especially in the <65-year group

Deslignificación de pasta kraft de Pinus radiata con una levadura genéticamente modificada para producir lacasa

Una posible aplicación biotecnológica de las lacasas fúngicas es el blanqueo de pasta de papel mediante la degradación de la lignina en la pasta cruda. Para ello es necesaria su producción a bajo coste y a concentraciones superiores a las secretadas por los hongos de forma natural. La expresión heteróloga en levaduras es una alternativa para su producción a mayor escala. En el presente trabajo se ha realizado la expresión heteróloga del gen cglcc1, responsable de la producción de lacasa en el hongo basidiomiceto Coriolopsis gallica, en la levadura Kluyveromyces lactis. Posteriormente y para verificar si la capacidad deslignificante se mantiene en la levadura, se ha tratado una pasta kraft de Pinus radiata con la cepa recombinante. Tras el tratamiento, el número kappa disminuyó en un 13%, mientras que el contenido en lignina lo hizo en un 22%, corroborando así el efecto deslignificador. Se concluye que el empleo de microorganismos carentes de actividades celulolíticas y genéticamente modificados para producir altos niveles de actividad lacasa constituye una opción para deslignificar aplicable a procesos de blanqueo de pasta de celulosa.Peer Reviewe

Comparative analysis of laccase-isozymes patterns of several related Polyporaceae species under different culture conditions

The study of isozymes has to date been successfully applied in the identification of a number of different microorganisms, particularly fungi. Trametes sp. I-62 (CECT20197) is a white-rot fungus with potential biotechnological applications. It has been identified as Trametes on the basis of the mycelium morphology, but the features observed are not sufficient for its classification at the species level. Given that this strain produces a very characteristic laccase isozyme pattern, in the present work we compared its isozyme profile with the profiles produced by ten other very closely phylogenetically related fungi from the Polyporaceae family. The data indicates that Trametes sp. I-62 could not be included in any of the taxonomically related species which were analysed in the present work. Extracellular laccases were detected in nine of the fungi studied and in four of them namely Trametes subectypus, Trametes pavonia, Trametes ochracea and Trametes gallica, this is the first report of such activity. Given that phylogenetically related fungi growing in the same culture conditions exhibit different laccase patterns, these isozymes could be used as an additional criterion for fungal identification

Efectos de un programa piloto de desarrollo cognitivo ‘teoría de la mente’ en tres niños con autismo: Componente emocional

Introduction. Theory of mind is defined as the capacity to predict, understand and act when faced with other people’s behaviour, their knowledge, their intentions, their emotions and their beliefs. It is proposed as a feasible alternative for establishing a programme adapted to the characteristics of children diagnosed with autism spectrum disorder. Case reports. The effect of a ‘theory of mind’ cognitive development pilot programme on the emotional skills of three children with autism spectrum disorder is reported. Case 1: 9-year-old boy, with scarce emotional identification and expression, as well as difficulties to hold fluent and coherent conversations. Case 2: 10-year-old boy, with mechanical, not very fluent language, and difficulties to start and maintain a conversation. Case 3: 8-year-old girl who presents deficits in the non-verbal communicative behaviours used in social interaction and difficulties to adapt to situations other than everyday ones. In the three cases there is an improvement in the emotional capacities following implementation of the programme; moreover, their parents, teachers or therapists perceived positive changes in the children’s adaptive skills. Conclusions. The methodological and structural aspects of the cognitive development programme were well-suited to the children with autism who took part in the research study. Due to the preliminary nature of this study, it is suggested that future research should utilise a larger sample and a double-blind design with randomised case-controls that allow the findings to be generalised. © 2016 Revista de Neurologí[email protected]

Structural close-related aromatic compounds have different effects on laccase activity and on lcc gene expression in the ligninolytic fungus Trametes sp. I-62

Nine phenolic compounds (p-coumaric acid, ferulic acid, guaiacol, syringol, p-methoxyphenol, pyrocatechol, phloroglucinol, 3,5-dihydroxybenzoic acid, and syringaldazine) were tested for their ability to increase laccase production in the ligninolytic basidiomycete Trametes sp. I-62. All these compounds resulted in increases in laccase activity, with the highest levels being detected in the presence of p-coumaric acid (273-fold) and guaiacol (73-fold). The three laccase isozyme genes in this fungus lcc1, lcc2, and lcc3 are differentially expressed in the presence of some of these aromatics with total lcc transcript levels differing markedly depending on the aromatic compound tested. Guaiacol (the best inducer of lcc gene transcription) and p-coumaric acid selectively induced expression of lcc1 and lcc2; ferulic acid induced lcc3 expression, while 3,5-dihydroxybenzoic acid had no marked effect on laccase gene transcription. The results demonstrate that close-related aromatic compounds appear to have different effects on both laccase activity levels and lcc gene expression in this basidiomycete. © 2004 Elsevier Inc. All rights reserved

Deslignificación de pasta kraft de Pinus radiata mediante tratamiento con una levadura transformada para producir lacasas

Cellulose pulp bleaching is one of the main biotechnological applications of fungal laccases due to their capacity to degrade lignin from the unbleached pulp. For this application, not only a low cost enzyme production, but also higher enzyme concentrations than those obtained by its natural producers are needed. Heterologous expression of laccase in yeasts is an option for producing these enzymes at industrial scale. In this work the heterologous expression of the cglcc1 gene, responsible for laccase production in the basidiomicetous fungus Coriolopsis gallica, in the yeast Kluyveromyces lactis has been tested. In order to know if the transformed yeast obtains delignificant capability, a Pinus radiata kraft pulp has been incubated with it. After the treatment, an important decrease in kappa number (13%) and in lignin content (22%) has been observed. These results showed the delignificant capacity of this transformed yeast. It can be concluded that the employment of genetically modified microorganisms, without cellulolitic activity, to produce high laccase levels could be a feasible option to delignify cellulose pulps with a potential application in cellulose pulp bleaching.Una posible aplicación biotecnológica de las lacasas fúngicas es el blanqueo de pasta de papel mediante la degradación de la lignina en la pasta cruda. Para ello es necesaria su producción a bajo coste y a concentraciones superiores a las secretadas por los hongos de forma natural. La expresión heteróloga en levaduras es una alternativa para su producción a mayor escala. En el presente trabajo se ha realizado la expresión heteróloga del gen cglcc1, responsable de la producción de lacasa en el hongo basidiomiceto Coriolopsis gallica, en la levadura Kluyveromyces lactis. Posteriormente y para verificar si la capacidad deslignificante se mantiene en la levadura, se ha tratado una pasta kraft de Pinus radiata con la cepa recombinante. Tras el tratamiento, el contenido en lignina disminuyó en un 22% (aunque el número kappa solo disminuyó en un 13%, posiblemente por interferencias con el microorganismo), corroborando así el efecto deslignificador. Se concluye que el empleo de microorganismos carentes de actividades celulolíticas y genéticamente modificados para producir altos niveles de actividad lacasa constituye una opción para deslignificar aplicable a procesos de blanqueo de pasta de celulosa

Biochemical study of the extracellular aspartyl protease Eap1 from the phytopathogen fungus Sporisorium reilianum

In this work, the extracellular protease Eap1 from Sporisorium reilianum was characterized in solid and liquid cultures using different culture media. The results showed that Eap1 was produced in all media and under all culture conditions, with the most activity in solid culture at an acidic pH of 3-5. Following purification, the 41 kDa protease demonstrated aspartyl protease activity. The enzyme was stable at a wide range of temperatures and pH values, but 45 C and pH 3 were optimal. The Km and Vmax values obtained were 0.69 mg/mL and 0.66 μmol/min, respectively, with albumin as the substrate. Eap1 degraded hemoglobin as well as proteins obtained from corn germ, roots, stems and slides at pH 3 and also had milk-clotting activity. Sequencing analysis showed that this protein has 100% similarity to the peptide sequence theoretically obtained from the sr11394 gene, which encodes an aspartyl protease secreted by S. reilianum. © 2013 Elsevier Ltd. All rights reserved.Fondo Mixto-Consejo Nacional de Ciencia y Tecnología; the government of the state of Hidalgo (FOMIXCONACyT); Fondo de Ciencia Básica SEP-CONACyTPeer Reviewe

Melanoidin-containing wastewaters induce selective laccase gene expression in the white-rot fungus Trametes sp. I-62

Wastewaters generated from the production of ethanol from sugar cane molasses may have detrimental effects on the environment due to their high chemical oxygen demand and dark brown color. The color is mainly associated with the presence of melanoidins, which are highly recalcitrant to biodegradation. We report here the induction of laccases by molasses wastewaters and molasses melanoidins in the basidiomycetous fungus Trametes sp. I-62. The time course of effluent decolorization and laccase activity in the culture supernatant of the fungus were correlated. The expression of laccase genes lcc1 and lcc2 increased as a result of the addition of complete molasses wastewater and its high molecular weight fraction to fungal cultures. This is the first time differential laccase gene expression has been reported to occur upon exposure of fungal cultures to molasses wastewaters and their melanoidins. © 2007 Elsevier Masson SAS. All rights reserved