Study of steam explosion pretreatment and preservation methods of commercial cellulose

Steam explosion (150 – 200 ºC, 5 – 30 min) was performed on a commercial cellulose presented in two configurations (fiberized and compact sheet) and its effect on their chemical and physical properties was studied, along with the influence of two different preservation methods (acetone drying and freezing) after pretreatment. No degradation compounds were produced during pretreatment, although solid recovery (RS) decreased with temperature from 90% to 62%. Similar particle size and surface conditions (increased porosity) were found for both types of pretreated samples despite the extremely different initial configuration. Crystallinity diminished for 150 ºC samples, but 200 ºC pretreatment promoted recrystallization. Pretreatment also reduced polymerization degree, although enzymatic accessibility did not improve. Both acetone and freezing processes extremely affected cellulose properties. Acetone drying counterbalanced crystallinity and enzymatic accessibility variations of pretreated samples, while decreasing polymerization degree to 302. Freezing dramatically decreased enzymatic accessibility of pretreated samples down to 15.8%.UIC-Consejería de Educación Junta de Castilla y León, University of Valladoli

Recovery of proteins from biomass grown in pig manure microalgae-based treatment plants by alkaline hydrolysis and acidic precipitation

Producción CientíficaThe influence of three variables on key parameters of the protein extraction process (an alkaline hydrolysis followed by an acidic precipitation) for biomass from innovative photo-bioreactors for pig manure treatment was evaluated. Alkaline hydrolysis provided high solubilisation values (up to 66.5% of the biomass), augmenting with increasing values of the three studied variables (NaOH concentration, temperature and time). Nevertheless, moderate total (13.2%) and protein extraction yields (16.9%) were obtained, which was attributable to protein denaturation or to the low effectivity of the precipitation method. Extracts rich in proteins (53.5%–77.9%) with suitable amino acid profiles were obtained, but significant amounts of the initial lipids (up to 44.6%) were co-extracted probably due to fatty acids saponification. These results establish the first step for future studies in enhancing cell wall disruption and protein recovery by coupling alkaline hydrolysis with other mechanical pre-treatments, while considering alternative separation and purification methods.Junta de Castilla y León (Projects UIC 071 / CLU 2017-09 / VA080G18)Ministerio de Ciencia, Innovación y Universidades (Project CTQ2017-84006-C3-1-R)EU-FEDER (Projects CLU 2017-09 / CTQ2017-84006-C3-1-R

Ozonolysis: an advantageous pretreatment for lignocellulosic biomass revisited.

Ozonolysis, as a lignocellulosic biomass pretreatment, goes back to 80s; however, in the last years it is becoming widespread again owing to its efficiency and mild operation conditions. Ozone reacts preferably with lignin than carbohydrates, promoting biomass destructuration and delignification, and so the sugar release by enzymatic hydrolysis. The hydrolysate from pretreated biomass has being used as sugars source for second-generation fuels production, mainly ethanol, methane and hydrogen. Short-chain carboxylic acids are the main inhibitory compounds generated, being properly removed by water washing. The most common inhibitory compounds reported for other pretreatments, furfural and HMF (5-hydroxymethylfurfural) , are not found in ozone-pretreated hydrolysates. Composition of pretreated biomass and ozone consumption depends on several process parameters: reactor design, moisture content, particle size, pH, reaction time, ozone/air flow and ozone concentration. Additional studies are necessary to clarify process parameters effec

Breakthroughs in bioalcohol production from microalgae: Solving the hurdles

Bioethanol production from microalgae biomass has been proposed as an innovative alternative to substitute fossil fuel sources. Unlike other renewable sources (e.g., lignocellulosic materials), microalgae biomass has no lignin, which makes the carbohydrate extraction process easier and eventually it should help to develop cleaner and safer bioethanol production processes. Carbohydrates in microalgae can be present in a variety of forms (cellulose, starch, and/or glycogen) and located in different regions of the cells (inner, inside, outside). Carbohydrate type, location, and concentration will strongly depend on cultivation and operation conditions with concentrations ranging from 15% to 50%. Several steps must be applied to obtain bioethanol from this biomass. First, different methods can be employed to disrupt the cell wall and release the carbohydrates such as physical-mechanicals, chemicals, and/or a combination of them. After that, enzymatic hydrolysis could be required to convert the carbohydrates into simple sugars. Finally, a yeast or bacteria fermentation stage is performed to transform these sugars into ethanol. However, it is imperative that the principal parameters of these different steps should be optimized during the bioethanol production before industrial implementation, and more research on economic and life cycle analysis is needed to ensure the economic feasibility of the process.COS

Saccharification of microalgae biomass obtained from wastewater treatment by enzymatic hydrolysis. Effect of alkaline-peroxide pretreatment

An enzymatic method for the carbohydrate hydrolysis of different microalgae biomass cultivated in domestic (DWB) and pig manure (PMWB) wastewaters, at different storage conditions (fresh, freeze-dried and reconstituted), was evaluated. The DWB provided sugars yields between 40 and 63%, although low xylose yields (< 23.5%). Approximately 2% of this biomass was converted to byproducts as succinic, acetic and formic acids. For PMWB, a high fraction of the sugars (up to 87%) was extracted, but mainly converted into acetic, butyric and formic acids, which was attributed to the bacterial action. In addition, the performance of an alkaline-peroxide pretreatment, conducted for 1 hour, 50ºC and H2O2 concentrations from 1 to 7.5% (w/w), was essayed. The hydrolysis of pretreated microalgae supported a wide range of sugars extraction for DWB (55-90%), and 100% for PMWB. Nevertheless, a large fraction of these sugars (~30% for DWB and 100% for PMWB) was transformed to byproducts.INIA MICINN Junta de Castilla y Leó

5ª Jornada de Doctorandos

Optimization of protein extraction from microalgae grown in wastewaters: Effect of operational variables of alkaline hydrolys

Bio.Iberoamérica 2016: Biotecnología integrando continentes

La biomasa como fuente renovable de biocombustibles ha supuesto uno de los campos más ricos en investigación, y durante los últimos 50 años, las microalgas en especial. Sus ventajas, entre ellas su capacidad para crecer en cualquier tipo de medio acuático, hacen de la biomasa microalgal un método eficaz de tratamiento de aguas residuales con altos contenidos en nutrientes, difíciles de purificar mediante métodos convencionales. Aplicando el concepto de biorefinería, la biomasa algal generada en el tratamiento pasa de ser un subproducto o residuo a ser considerado una fuente renovable de numerosos productos mediante el aprovechamiento de sus distintas fracciones. Este trabajo estudia la valorización de la fracción carbohidrato de los consorcios microalgas/bacterias para la producción de alcoholes (etanol o butanol) con una gran proyección como biocombustibles. Dentro de este proceso, la hidrolisis enzimática es la alternativa más empleada para la liberación de azúcares fermentables. Este trabajo tiene como objetivo el estudio de la influencia de las condiciones de cultivo y operación durante el tratamiento de aguas residuales sobre la hidrolisis enzimática de los diferentes tipos de biomasa algal. Se ha trabajado con 11 muestras diferentes, variando el inóculo empleado, el agua residual a tratar, el tipo de reactor y el procesado posterior. La hidrólisis enzimática se llevó a cabo con un 6% m/m de biomasa, empleando cocteles de enzimas comerciales de celulasa y b-glucosidasa, con tiempos de operación de 48 horas. Se han analizado tanto la liberación de azúcares como la producción de posibles compuestos inhibidores de etapas posteriores de fermentación, como ácidos orgánicos y furanos. El intervalo de resultados es muy amplio, con rendimientos de liberación de azúcares que van desde nulos hasta 93.7% de glucosa y 23.5% de xilosa para biomasa alimentada con agua residual doméstica y fertilizantes, liofilizada. Los principales inhibidores hallados son ácido acético y ácido fórmico, con los mayores valores en reactores de capa fina alimentados con purines. Se concluye que la hidrólisis enzimática es un método eficaz de sacarificación de biomasa microalgal, y que la influencia de los parámetros de cultivo, sobre todo la relación microalgas/bacterias, es muy importante al optimizar el proces

Effectiveness of a cognitive behavioral intervention in patients with medically unexplained symptoms: cluster randomized trial

BACKGROUND: Medically unexplained symptoms are an important mental health problem in primary care and generate a high cost in health services.Cognitive behavioral therapy and psychodynamic therapy have proven effective in these patients. However, there are few studies on the effectiveness of psychosocial interventions by primary health care. The project aims to determine whether a cognitive-behavioral group intervention in patients with medically unexplained symptoms, is more effective than routine clinical practice to improve the quality of life measured by the SF-12 questionary at 12 month. METHODS/DESIGN: This study involves a community based cluster randomized trial in primary healthcare centres in Madrid (Spain). The number of patients required is 242 (121 in each arm), all between 18 and 65 of age with medically unexplained symptoms that had seeked medical attention in primary care at least 10 times during the previous year. The main outcome variable is the quality of life measured by the SF-12 questionnaire on Mental Healthcare. Secondary outcome variables include number of consultations, number of drug (prescriptions) and number of days of sick leave together with other prognosis and descriptive variables. Main effectiveness will be analyzed by comparing the percentage of patients that improve at least 4 points on the SF-12 questionnaire between intervention and control groups at 12 months. All statistical tests will be performed with intention to treat. Logistic regression with random effects will be used to adjust for prognostic factors. Confounding factors or factors that might alter the effect recorded will be taken into account in this analysis. DISCUSSION: This study aims to provide more insight to address medically unexplained symptoms, highly prevalent in primary care, from a quantitative methodology. It involves intervention group conducted by previously trained nursing staff to diminish the progression to the chronicity of the symptoms, improve quality of life, and reduce frequency of medical consultations. TRIAL REGISTRATION: The trial was registered with ClinicalTrials.gov, number NCT01484223 [http://ClinicalTrials.gov].S

Validation of a histologic scoring index for C3 glomerulopathy

12 p.-4 fig.-4 tab.Rationale & objective: A previous study that evaluated associations of kidney biopsy findings with disease progression in patients with C3 glomerulopathy (C3G) proposed a prognostic histologic index (C3G-HI) that has not yet been validated. Our objective was to validate the performance of the C3G-HI in a new patient population.Study design: Multicenter, retrospective cohort study.Setting & participants: 111 patients fulfilling diagnostic criteria of C3G between January 1995 and December 2019, from 33 nephrology departments belonging to the Spanish Group for the Study of Glomerular Diseases (GLOSEN).Predictors: Demographic, clinical parameters, C3G-HI total activity score, and the C3G-HI total chronicity score.Outcome: Time to kidney failure.Analytical approach: Intraclass correlation coefficients and κ statistic were used to summarize inter-rater reproducibility for assessment of histopathology in kidney biopsies. The nonlinear relationships of risk of kidney failure with the total activity score and total chronicity score were modeled using Cox proportional hazards analysis that incorporated cubic splines.Results: The study group included 93 patients with C3 glomerulonephritis and 18 with dense-deposit disease. Participants had an overall meanage of 35±22 (SD) years. Forty-eight patients (43%) developed kidney failure after a mean follow-up of 65±27 months. The overall inter-rater reproducibility was very good for the total activity score (intraclass correlation coefficient [ICC]=0.63) and excellent for total chronicity score (ICC=0.89). Baseline estimated glomerular filtration rate (eGFR), 24-hour proteinuria, and treatment with immunosuppression were the main determinants of kidney failure in a model with only clinical variables. Only tubular atrophy and interstitial fibrosis were identified as predictors in a model with histological variables. When the total activity score and total chronicity score were added to the model, only the latter was identified as an independent predictor of kidney failure.Limitations: Only a subset of the kidney biopsies was centrally reviewed. Residual confounding.Conclusions: We validated the performance of C3G-HI as a predictor of kidney failure in patients with C3G. The total chronicity score was the principal histologic correlate of kidney failure.Work in this study was supported by the Instituto de Salud Carlos III /Fondo Europeo de Desarrollo Regional (ISCIII/FEDER) grant PI16/01685 and Red de Investigación Renal (RedInRen) (RD12/0021/0029) (to MP), the Autonomous Region of Madrid (S2017/BMD-3673) (to MP); EGdeJ is supported by the Spanish “Ministerio de Ciencia, Innovación y Universidades" (RYC-2013-13395 and RTI2018-095955-B-100).Peer reviewe

Association Between Preexisting Versus Newly Identified Atrial Fibrillation and Outcomes of Patients With Acute Pulmonary Embolism

Background Atrial fibrillation (AF) may exist before or occur early in the course of pulmonary embolism (PE). We determined the PE outcomes based on the presence and timing of AF. Methods and Results Using the data from a multicenter PE registry, we identified 3 groups: (1) those with preexisting AF, (2) patients with new AF within 2 days from acute PE (incident AF), and (3) patients without AF. We assessed the 90-day and 1-year risk of mortality and stroke in patients with AF, compared with those without AF (reference group). Among 16 497 patients with PE, 792 had preexisting AF. These patients had increased odds of 90-day all-cause (odds ratio [OR], 2.81; 95% CI, 2.33-3.38) and PE-related mortality (OR, 2.38; 95% CI, 1.37-4.14) and increased 1-year hazard for ischemic stroke (hazard ratio, 5.48; 95% CI, 3.10-9.69) compared with those without AF. After multivariable adjustment, preexisting AF was associated with significantly increased odds of all-cause mortality (OR, 1.91; 95% CI, 1.57-2.32) but not PE-related mortality (OR, 1.50; 95% CI, 0.85-2.66). Among 16 497 patients with PE, 445 developed new incident AF within 2 days of acute PE. Incident AF was associated with increased odds of 90-day all-cause (OR, 2.28; 95% CI, 1.75-2.97) and PE-related (OR, 3.64; 95% CI, 2.01-6.59) mortality but not stroke. Findings were similar in multivariable analyses. Conclusions In patients with acute symptomatic PE, both preexisting AF and incident AF predict adverse clinical outcomes. The type of adverse outcomes may differ depending on the timing of AF onset.info:eu-repo/semantics/publishedVersio