Hydrogen and methane production through two stage anaerobic digestion of straw residues.

Anaerobic digestion of agricultural waste can contribute to the European renewable energy needs. The 71% of the 20,000 anaerobic digestion plants in operation already uses these agro-waste as feedstock; part of these plants can be converted into two stage processes to produce hydrogen and methane in the same plant. Biomethane enriched in hydrogen can replace natural gas in grids while contributing to the sector decarbonisation. Straw is the most abundant agricultural residue (156 Mt/y) and its conventional final fate is uncontrolled soil disposal, landfilling, incineration or, in the best cases, composting. The present research work focuses on the fermentation of spent mushroom bed, an agricultural lignocellulosic byproduct, composed mainly from wheat straw. The substrate has been characterized and semi-continuous tests were performed evaluating the effect of the hydraulic retention time on hydrogen and volatile fatty acids production. It was found that all the tests confirmed the feasibility of the process even on this lignocellulosic substrate, and also, it was identified HRT 4.0 d as the best option to optimize the productivity of volatile fatty acids (17.09 gCODVFAs/(KgVS*d)), and HRT 6.0 d for hydrogen (7.98 LH2/(KgVS*d)). The fermentation effluent was used in biomethanation potential tests to evaluate how this process affects a subsequent digestion phase, reporting an increase in the energetical feedstock exploitation up to 30%.

Producing volatile fatty acids and polyhydroxyalkanoates from foods by-products and waste: A review.

Dairy products, extra virgin olive oil, red and white wines are excellent food products, appreciated all around the world. Their productions generate large amounts of by-products which urge for recycling and valorization. Moreover, another abundant waste stream produced in urban context is the Organic Fraction of Municipal Solid Wastes (OFMSW), whose global annual capita production is estimated at 85 kg. The recent environmental policies encourage their exploitation in a biorefinery loop to produce Volatile Fatty Acids (VFAs) and polyhydroxyalkanoates (PHAs). Typically, VFAs yields are high from cheese whey and OFMSW (0.55-0.90 gCOD_VFAs/gCOD), lower for Olive Mill and Winery Wastewaters. The VFAs conversion into PHAs can achieve values in the range 0.4-0.5 gPHA/gVSS for cheese whey and OFMSW, 0.6-0.7 gPHA/gVSS for winery wastewater, and 0.2-0.3 gPHA/gVSS for olive mill wastewaters. These conversion yields allowed to estimate a huge potential annual PHAs production of about 260 M tons.

Single Cell Proteins production from food processing effluents and digestate.

The increase in human population determines a higher proteins request to sustain the feed demand for animals and aquaculture. Single Cell Proteins (SCPs) consist of mixed protein from pure and mixed culture of bacteria, fungi, algae, and yeast, which are grown and harvested to accomplish the food requirement of human and animals. This work investigated the production of Saccharomyces cerevisiae to be used as SCPs for animal feeding. The effluent of candies production process, rich in sugars, about 40 g/L, and agricultural digestate rich in nitrogen and other macro and micronutrients, were used for the yeast's growth. Preliminary batch tests demonstrated that aerobic conditions optimized the biomass growth. Then, continuous aerobic tests were conducted at different dilution rates. The dilution rate of 0.50 d-1, corresponding to a hydraulic retention time of 2 days, optimized both the biomass productivity of 0.25 g/L per day and the protein content of 28% w/w. The analysis of the aminoacidic profile demonstrated that obtained SCPs could be used as an integrator of feed for fish and monogastric animals. On the contrary, they were not suitable for pet feed as all the amino acids concentrations were lower than required standards. These results suggested that anaerobic digesters in the agricultural sector can be transformed into small biorefineries for microbial protein production.

Electroporation and cell killing by milli- to nanosecond pulses and avoiding neuromuscular stimulation in cancer ablation.

Ablation therapies aim at eradication of tumors with minimal impact on surrounding healthy tissues. Conventional pulsed electric field (PEF) treatments cause pain and muscle contractions far beyond the ablation area. The ongoing quest is to identify PEF parameters efficient at ablation but not at stimulation. We measured electroporation and cell killing thresholds for 150 ns-1 ms PEF, uni- and bipolar, delivered in 10- to 300-pulse trains at up to 1 MHz rates. Monolayers of murine colon carcinoma cells exposed to PEF were stained with YO-PRO-1 dye to detect electroporation. In 2-4 h, dead cells were labeled with propidium. Electroporation and cell death thresholds determined by matching the stained areas to the electric field intensity were compared to nerve excitation thresholds (Kim et al. in Int J Mol Sci 22(13):7051, 2021). The minimum fourfold ratio of cell killing and stimulation thresholds was achieved with bipolar nanosecond PEF (nsPEF), a sheer benefit over a 500-fold ratio for conventional 100-µs PEF. Increasing the bipolar nsPEF frequency up to 100 kHz within 10-pulse bursts increased ablation thresholds by < 20%. Restricting such bursts to the refractory period after nerve excitation will minimize the number of neuromuscular reactions while maintaining the ablation efficiency and avoiding heating.

Biodiesel, biogas and fermentable sugars production from Spent coffee Grounds: A cascade biorefinery approach.

Spent coffee grounds are rich in high-value compounds, such as saturate and unsaturated fatty acids, and polysaccharides. Therefore, this work investigated a cascade biorefinery to produce: i) biodiesel from coffee oils, ii) cellulose- and hemicellulose-derived fermentable sugars and iii) biomethane from the residual solid fraction after sugars extraction. Transesterification reached the best performances of 86% w/w of fatty acid methyl esters using 1:8 coffee oil/methanol ratio and 2% w/w of KOH as catalyst. The use of glycerol for the pretreatment of spent coffee grounds allowed the internal circulation of a process leftover from transesterification; thus, avoiding the use of clean water. In the best conditions, the total released fermentable sugars were about 40-50% (w/w) on dry weight basis. The low content of easily degradable compounds led to a low methane production of 50 LCH4/kgVS, indicating the need to search for better performing alternatives to close the biorefinery loop.

Influence of different household Food Wastes Fractions on Volatile Fatty Acids production by anaerobic fermentation.

This research investigated for the first time the influence of the single fractions (proteins, lipids, starch, cellulose, fibers and sugars) composing Household Food Wastes on Volatile Fatty Acids (VFA). A production at different pH (uncontrolled, 5.5 and 7.0): both the amount and profile of VFA were investigated. It was found that fractions rich in proteins and starch led to the greatest VFA productions (12-15 g/L), especially at neutral pH condition. On the contrary, fractions rich in cellulose, fibers, and sugars showed a very low VFA production (<2 g/L). The chemical nature of HFW influenced the speciation of the microbial communities too. Lactobacillaceae family was highly represented in proteins-, starch-, fibers and sugars-rich substrates and Atopobiaceae, Eggerthellaceae, Acidaminococcaceae and Veillonellaceae displayed positive correlation to VFAs production. Instead, Comamonadaceae showed high relative abundance in lipids- and cellulose-rich fraction and was negatively correlated to the VFAs generation.

Life Cycle Assessment of waste disposal from olive oil production: Anaerobic digestion and conventional disposal on soil.

Extra virgin olive-oil (EVO) production is an important economic activity for several countries, especially in the Mediterranean area such as Spain, Italy, Greece and Tunisia. The two major by-products from olive oil production, solid-liquid Olive Pomace (OP) and the Olive Mill Waste Waters (OMWW), are still mainly disposed on soil, in spite of the existence of legislation which already limits this practice. The present study compares the environmental impacts associated with two different scenarios for the management of waste from olive oil production through a comparative Life Cycle Assessment (LCA). The two alternative scenarios are: (I) Anaerobic Digestion and (II) Disposal on soil. The analysis was performed through SimaPro software and the assessment of the impact categories was based on International Life Cycle Data and Cumulative Energy Demand methods. Both the scenarios are mostly related to the cultivation and harvesting phase and are highly dependent on the irrigation practice and related energy demand. Results from the present study clearly show that the waste disposal on soil causes the worst environmental performance of all the impact categories considered here. Important environmental benefits have been identified when anaerobic digestion is chosen as the final treatment. It was consequently demonstrated that anaerobic digestion should be a feasible alternative for olive mills, to produce biogas from common olive oil residues, reducing the environmental burden and adding value to the olive oil production chain.

Volatile fatty acids production from food wastes for biorefinery platforms: A review.

Volatile fatty acids (VFAs) are a class of largely used compounds in the chemical industry, serving as starting molecules for bioenergy production and for the synthesis of a variety of products, such as biopolymers, reduced chemicals and derivatives. Because of the huge amounts of food waste generated from household and processing industry, 47 and 17 million tons per year respectively only in the EU-28 Countries, food wastes can be the right candidate for volatile fatty acids production. This review investigates all the major topics involved in the optimization of VFAs production from food wastes. Regarding the best operative conditions for the anaerobic fermenter controlled pH in the neutral range (6.0-7.0), short HRT (lower than 10 days), thermophilic temperatures and an organic loading rate of about 10 kgVS/m3d, allowed for an increase in the VFAs concentration between 10 and 25%. It was also found that additions of mineral acids, from 0.5 to 3.0%, and thermal pretreatment in the range 140-170 °C increase the organic matter solubilisation. Applications of VFAs considered in this study were biofuels and bioplastics production as well as nutrients removal in biological wastewater treatment processes.

Recent developments in biohythane production from household food wastes: A review.

Biohythane is a hydrogen-methane blend with hydrogen concentration between 10 and 30% v/v. It can be produced from different organic substrates by two sequential anaerobic stages: a dark fermentation step followed by a second an anaerobic digestion step, for hydrogen and methane production, respectively. The advantages of this blend compared to either hydrogen or methane, as separate biofuels, are first presented in this work. The two-stage anaerobic process and the main operative parameters are then discussed. Attention is focused on the production of biohythane from household food wastes, one of the most abundant organic substrate available for anaerobic digestion: the main milestones and the future trends are exposed. In particular, the possibility to co-digest food wastes and sewage sludge to improve the process yield is discussed. Finally, the paper illustrates the developments of biohythane application in the automotive sector as well as its reduced environmental burden.

Enzymatic hydrolysis at high dry matter content: The influence of the substrates' physical properties and of loading strategies on mixing and energetic consumption.

The present work investigates the impact of the physical properties and loading strategies of wheat straw and miscanthus on enzymatic hydrolysis at high DM concentration. Three parameters have been chosen to evaluate the enzymatic hydrolysis performance: (i) the mixing time, (ii) the energetic mixing consumption and (iii) the glucose concentration. It was demonstrated that the hydrolysis of miscanthus is easy to perform and has low viscosity. On the contrary, the higher porosity grade of wheat straw than miscanthus (73% against 52%) contributed to have a very high viscosity at 20% w/w DM. The development of a fed-batch strategy allowed the reduction of viscosity inducing the energetic consumption lowering from 30 kJ to 10 kJ. It has been also proven that the miscanthus addition in wheat straw achieved to decrease mixing energy consumption at 5-8 kJ, when it represented more than 30% of the total mass of the reaction medium.

Optimization of biogas production from coffee production waste.

This study was conducted to investigate the effects of chemical pretreatments on biogas production from coffee waste. After the preparation of a mixture of coffee waste with a TS concentration of 10%w/w, basic and acid pretreatments were conducted in batch mode and their performances were compared with the biogas produced from a mixture without any pretreatment stage. The basic pretreatment demonstrated a very good action on the hydrolysis of the lignin and cellulose, and permitted a biogas production of about 18NL/L with a methane content of almost 80%v/v. Thus, the basic pretreatment has been used to scale-up the process. The coffee refuse was has been carried out in a 45L anaerobic reactor working in continuous mode and in a mesophilic condition (35°C) with a Hydraulic Retention Time (HRT) of about 40days. A high biogas production of 1.14NL/Ld, with a methane percentage of 65%v/v was obtained, thus permitting a process yield of about 83% to be obtained.

[Diagnosis of heart failure in general medicine: role of cerebral natriuretic peptide. Results of a pilot study of a population sample from Calabria]. / La diagnosi di scompenso cardiaco in medicina generale: ruolo del peptide natriuretico cerebrale. Risultati di uno studio pilota su di un campione di popolazione della Calabria.

BACKGROUND: The aim of this study was to evaluate the usefulness of brain natriuretic peptide (BNP) in diagnosing congestive heart failure (CHF), in an unselected population. METHODS: Eighty-three patients (47 men, 36 women, mean age 70 +/- 10 years) were referred to our hospital ambulatory from their general practitioners, with a diagnosis of CHF. RESULTS: Clinical-instrumental evaluation confirmed diagnosis in 45 patients (54%) (group A), and excluded it in the remaining 38 (46%) (group B). There were no differences between groups regarding age, weight, height, heart rate, blood pressure. Statistically significant differences between groups were found regarding ejection fraction (44 +/- 10% group A vs 60 +/- 7% group B, p < 0.01), and BNP blood concentration (162 +/- 226 pg/ml group A vs 73 +/- 23 pg/ml group B, p < 0.01). Forty-two patients in group A (93%) and 25 in group B (65%) had a BNP value > 20 pg/ml (p < 0.05). Using this cut-off value, sensitivity was 93%, specificity 34%, negative predictive value 81% and positive predictive value 62%. Forty-two patients in group A (93%) and 14 in group B (36%) had an "abnormal" electrocardiogram (p < 0.01). The presence of electrocardiographic abnormalities showed a sensitivity for the diagnosis of CHF of 93%, specificity of 63%, negative predictive value of 89% and positive predictive value of 77%. CONCLUSIONS: In our population BNP dosage confirms the high negative predictive value reported in the literature and may be useful to exclude diagnosis of CHF in patients with suspect signs and symptoms.

Utilización de antibióticos en forma tópica en la prevención de infección de sitio quirúrgico / Use of antibiotics in topic form for prevention of surgical site infection

Antecedentes: la antibióticoprofilaxis sistemática preoperatoria ha demostrado ser efectiva en la disminución de la incidencia de infección de sitio quirúrgico (ISQ), no obstante en algunas circunstancias el ingreso de los mismos en la herida quirúrgica se ve limitado. La administración de antibióticos tópicos permite la llegada de drogas altamente concentradas aún en tejidos poco vascularizados. Objetivo: evaluar el efecto de la utilización de antibióticos en forma tópica como complemento de la antibióticoprofilaxis sistémica en la prevención de infección de heridas de sitio quirúrgico. Lugar de aplicación: Servicio de Emergencias y de Cirugía General, Hospital General de Referencia. Diseño: trabajo prospectivo, cohortes de asignación aleatoria, simple ciego. Material y métodos: fueron incluidos todos los pacientes sometidos a apendicetomía a cielo abierto en el período comprendido entre el 1 de enero y 31 de diciembre de 2000. Se dividió a la población en tres clases de acuerdo con la forma anatomopatológica del cuadro: 1) congestiva-flemosa, 2) supurada, 3) gangrenosa - perforada. Cada clase se subdividió en un grupo A (casos), quienes recibieron antibióticos tópicos y un grupo B (control), sin antibióticoprofilaxis tópica. En ambos grupos se utilizó antibióticoprofilaxis sistemática. Resultados: el grupo estudiado resultó de 114 pacientes. En el grupo A (n=58) se constatan 6 ISQ (10,30 por ciento), en el grupo B (n=56) se observaron 9 ISQ (16,07 por ciento). No obstante al ser sometidos al método de ji-cuadrado (x2) no se detectaron diferencias estadísticamente significativas (p>0.5). No se registraron reacciones adversas ni efectos colaterales atribuibles a la administración tópica de cefalotonina. Conclusiones: no se encontraron diferencias significativas con el agregado de antibióticoprofilaxis tópica a la sistemática. Continuamos el estudio sólo en la clase 3) gangrenosa - perforada donde la muestra es muy pequeña (A3n=14 casos; B3n=13 casos) y las diferencias fueron más marcadas aunque sin llegar a ser significativas

Utilización de antibióticos en forma tópica en la prevención de infección de sitio quirúrgico / Use of antibiotics in topic form for prevention of surgical site infection

Antecedentes: la antibióticoprofilaxis sistemática preoperatoria ha demostrado ser efectiva en la disminución de la incidencia de infección de sitio quirúrgico (ISQ), no obstante en algunas circunstancias el ingreso de los mismos en la herida quirúrgica se ve limitado. La administración de antibióticos tópicos permite la llegada de drogas altamente concentradas aún en tejidos poco vascularizados. Objetivo: evaluar el efecto de la utilización de antibióticos en forma tópica como complemento de la antibióticoprofilaxis sistémica en la prevención de infección de heridas de sitio quirúrgico. Lugar de aplicación: Servicio de Emergencias y de Cirugía General, Hospital General de Referencia. Diseño: trabajo prospectivo, cohortes de asignación aleatoria, simple ciego. Material y métodos: fueron incluidos todos los pacientes sometidos a apendicetomía a cielo abierto en el período comprendido entre el 1 de enero y 31 de diciembre de 2000. Se dividió a la población en tres clases de acuerdo con la forma anatomopatológica del cuadro: 1) congestiva-flemosa, 2) supurada, 3) gangrenosa - perforada. Cada clase se subdividió en un grupo A (casos), quienes recibieron antibióticos tópicos y un grupo B (control), sin antibióticoprofilaxis tópica. En ambos grupos se utilizó antibióticoprofilaxis sistemática. Resultados: el grupo estudiado resultó de 114 pacientes. En el grupo A (n=58) se constatan 6 ISQ (10,30 por ciento), en el grupo B (n=56) se observaron 9 ISQ (16,07 por ciento). No obstante al ser sometidos al método de ji-cuadrado (x2) no se detectaron diferencias estadísticamente significativas (p>0.5). No se registraron reacciones adversas ni efectos colaterales atribuibles a la administración tópica de cefalotonina. Conclusiones: no se encontraron diferencias significativas con el agregado de antibióticoprofilaxis tópica a la sistemática. Continuamos el estudio sólo en la clase 3) gangrenosa - perforada donde la muestra es muy pequeña (A3n=14 casos; B3n=13 casos) y las diferencias fueron más marcadas aunque sin llegar a ser significativas

Enfermedad de Ormond: a forma tumoral / Ormondïs disease: tumoral form

Objetivo: presentación de un caso de Enfermedad de Ormond a forma tumoral, tratado quirúrgicamente en nuestro hospital. Se hacen consideraciones etiológicas, anatomopatológicas y clínico-quirúrgicas, con el objetivo de realizar un aporte a la casuística. Lugar de aplicación: ervicio de Cirugía General Y Servicio de natomía Patológica del Hospital Interzonal General de Agudos General San Martín, La Plata. Material y método: se presenta un paciente de sexo masculino, de 61 años, intervenido quirúrgicamente en nuestro hospital. Resultados: Se expone el hallazgo quiúrgico y el informe de anatomía patológica por tratarse por una variante de escasa frecuencia. Conclusiones: es una patología cuya histogénesis es aún controvertida, como así también los factores etiológicos. Se presenta con sintomatología variada, debido a las múltiples loalizaciones que puede presentar. La topografía y forma de presentación de nuestro caso, es extremadamente rara.

Enfermedad de Ormond: a forma tumoral / Ormond´s disease: tumoral form

Objetivo: presentación de un caso de Enfermedad de Ormond a forma tumoral, tratado quirúrgicamente en nuestro hospital. Se hacen consideraciones etiológicas, anatomopatológicas y clínico-quirúrgicas, con el objetivo de realizar un aporte a la casuística. Lugar de aplicación: ervicio de Cirugía General Y Servicio de natomía Patológica del Hospital Interzonal General de Agudos General San Martín, La Plata. Material y método: se presenta un paciente de sexo masculino, de 61 años, intervenido quirúrgicamente en nuestro hospital. Resultados: Se expone el hallazgo quiúrgico y el informe de anatomía patológica por tratarse por una variante de escasa frecuencia. Conclusiones: es una patología cuya histogénesis es aún controvertida, como así también los factores etiológicos. Se presenta con sintomatología variada, debido a las múltiples loalizaciones que puede presentar. La topografía y forma de presentación de nuestro caso, es extremadamente rara. (AU)