Mixotrophic cultivation of microalgae provides a very promising alternative for producing carbohydrate-rich biomass to convert into bioethanol and value-added biocompounds, such as vitamins, ...pigments, proteins, lipids and antioxidant compounds. Spirulina platensis may present high yields of biomass and carbohydrates when it is grown under mixotrophic conditions using cheese whey. However, there are no previous studies evaluating the influence of this culture system on the profile of fatty acids or antioxidant compounds of this species, which are extremely important for food and pharmaceutical applications and would add value to the cultivation process. S. platensis presented higher specific growth rates, biomass productivity and carbohydrate content under mixotrophic conditions; however, the antioxidant capacity and the protein and lipid content were lower than that of the autotrophic culture. The maximum biomass yield was 2.98 ±0.07 g/L in growth medium with 5.0% whey. The phenolic compound concentration was the same for the biomass obtained under autotrophic and mixotrophic conditions with 2.5% and 5.0% whey. The phenolic compound concentrations showed no significant differences except for that in the growth medium with 10.0% whey, which presented an average value of 22.37±0.14 mg gallic acid/g. Mixotrophic cultivation of S. platensis using whey can be considered a viable alternative to reduce the costs of producing S. platensis biomass and carbohydrates, shorten cultivation time and produce carbohydrates, as it does not require adding expensive chemical nutrients to the growth medium and also takes advantage of cheese whey, an adverse dairy industry byproduct.
Limited fossil fuel reserves combined with greenhouse gas intensification due to CO2 emissions has encouraged research in renewable fuels. In this work, a flash pyrolysis study of elephant grass ...cultivars—Pennisetum purpureum Schum cultivar Mott (MEG), P. purpureum Schum cultivar Roxo (REG), and P. purpureum Schum cultivar Capiaçu (CEG)—was carried out. The biomasses were evaluated in terms of energy characterization by proximate and ultimate analysis, thermogravimetric analyses (TG/DTG), X‐ray diffraction (XRD), Fourier transform infrared (FTIR), and analytical pyrolysis (Py‐GC/MS) at 600°C. The characterization results showed that these biomasses have potential for energy applications and to produce valuable chemicals. The pyrolysis products produced were mainly oxygenated, including short‐chain organic acids (C1‐C4), furans, esters, aldehydes, ketone, and phenols. Although the obtained results were similar for the three biomasses with small variations in the yields of the pyrolysis products, the study reveals an important difference in terms of energy density. CEG was proven as the most promising elephant grass cultivar to be applied for fast pyrolysis to obtain bio‐oil due to its higher dry matter production (2115 t km−2), power generated (9529 MWh km−2), HHV (16.22 MJ kg−1), lower ash content (6.75%), higher volatile content (74.84%), and higher carbon content (42.57%).
•A domestic microwave (DMW) was for synthesis of crystalline porous materials.•A simple, fast and low-cost synthesis of MOFs was developed.•The approach allowed the control of the solvent losses and ...temperature.•DMW uses timed and pulsed power as the control method of the heating process.•The produced MOFs showed excellent chemical properties.
This work shows a facile modification of a modified domestic microwave oven that allows for the control of solvent losses and the monitoring of temperature during the synthesis of metal-organic frameworks (MOFs) MIL 100 under hydrofluoric acid-free conditions, HKUST-1 with unique properties, and MIL 88B. In order to obtain the best efficiency irradiation, a thermal mapping image from the domestic microwave DMW was obtained. The results showed that the chemical properties of the produced MOFs were excellent: the observed yield calculation and the BET surface area of the MIL-100 active crystals were 97% and 1300 m2g−1, respectively, and 90% and 1365 m2g−1, respectively for HKUST-1 with unique properties. A simple and low-cost alternative to a commercial microwave oven was developed, making it safer and its parameters controllable during the synthesis of MOFs.
In the present study, the transesterification of soybean oil with ethanol under supercritical conditions was investigated using a packed-bed tubular reactor. The experiments were performed with an ...oil/alcohol molar ratio of 1:40, a pressure of 15 MPa, and different conditions of temperature (573–673 K), flow rate (0.5–1.0 mL/min), and bed porosity (0.32–1.0). A phenomenological model was developed to describe and analyze the results. The highest ester yield (98.99%) was obtained for the lower bed porosity (0.32), under 673 K and 0.5 mL/min with a residence time of 5.44 min. The kinetic and dispersion coefficients were estimated using the particle swarm optimization algorithm, and the model fitted the experimental data with an R 2 coefficient of 0.97. The proposed kinetic model followed the behavior of the Arrhenius equations. Low values of dispersion were observed under conditions of lower flow rate and porosity. An analysis of the model allowed us to verify that the increase of the ester yield produced occurs at small values of the Reynolds number and high Peclet numbers.
Microalgae have a great potential to produce biofuels, but the cost is still too high mainly due to the biomass production. Mixotrophic cultivation has been pointed as microalgae cultivation mode for ...biomass/bioenergy production with lower cost. The proposals of this work were to cultivate
S. platensis
in autotrophic and mixotrophic medium using molasses as source of organic carbon and investigate the thermal behavior of obtained biomass by means of thermogravimetric analysis and pyrolysis (Py-GC/MS). The kinetics models proposed by Flynn and Wall and model-free kinetic were used to determine the activation energy. These data are important to projection of design, operation and modeling of thermochemical conversion system for microalgae. The use of molasses as supplement in culture medium for the growth of
S. platensis
was a good way to increase the biomass productivity and decrease the protein content. The Flynn–Wall and model-free kinetic methods were adequate to calculate activation energy on the conversion range of 0.20 to 0.80. The activation energies were 168–229 kJ mol
−1
(Flynn and Wall), 177–238 kJ mol
−1
(model-free kinetic) for mixotrophic biomass and 174–220 kJ mol
−1
(Flynn and Wall), 181–229 kJ mol
−1
(model-free kinetic) for autotrophic biomass. The compositions of volatile compounds produced by
S. platensis
biomass pyrolysis were different due to cultivation method that influenced the composition of biomass. Hydrocarbons, oxygenated and nitrogenated compounds were produced with different quantities. The volatile compounds content of phenols, oxygenated and nitrogenated increased and non-aromatic and aromatic hydrocarbons content decreased for pyrolysis of mixotrophic biomass. However, the mixotrophic cultivation has a great influence on the microalgae biomass production and should be a factor considered in thermal degradation project for microalgae.
Display omitted
•Long-term monitoring of different drivers of changes increases the effectiveness of protected areas.•Long-term Ecological Research Program helps detecting complex environmental ...changes.•The effects of disturbances on biodiversity and ecosystems were explored over 22 years in the central Cerrado.•Even in Protected Areas, changes in surroundings affect biodiversity and ecosystems.•Significant ecological changes were detected in responses to long-term stressors.
Protected areas (PAs) are a widely recognized tool for biodiversity and ecosystem conservation. However, megadiverse countries struggle to manage, maintain, and expand PAs as they face mounting human pressures. The Brazilian Cerrado biome (a biodiversity hotspot) is experiencing increasing land-use changes paired with a loss of natural vegetation, and only 3.2% of its land area is under strict protections. The Brazilian Long-Term Ecological Research Program (LTER) was created in 1997 to monitor long-term changes in protected and non-protected areas in Brazilian biomes. The Environmental Protected Area of the Gama and Cabeça de Veado (AGCV) watersheds in Central Brazil's core distribution of the Cerrado (Brasília, Federal District), was one of the first sites to participate in the Brazilian LTER. The main goal of the AGCV-LTER site is to monitor long-term changes and ecological processes in aquatic and terrestrial ecosystems in PAs that are surrounded by landscapes facing extreme ecosystem shifts. Over 22 years, we investigated the effects of drivers such as fire, noise and light pollution, eutrophication, and biological invasions on aquatic (invertebrates and water quality) and terrestrial ecosystems (vegetation, vertebrates, and invertebrates). The results indicate that even within a PA, changes in the surrounding landscape affects biodiversity and ecosystem functions, revealing the essential nature of continuous monitoring for biodiversity conservation.
The catalyst activity and resistance to coke deposition are of great importance for DRM reaction and the catalyst preparation method is one way to evaluate these parameters, besides improving the ...catalyst properties. Therefore, the effect of two catalyst preparation methods (incipient wetness impregnation (IWI) and all-in-one (AIO) methods) of ceria-alumina-supported Ni-based catalysts on dry reforming of methane reaction was investigated. The catalysts were characterized by several characterization techniques. All-in-one method provided greater dispersion and a higher reduced fraction for the catalyst than the IWI method, besides increasing the presence of weak basic sites, which decreases carbon deposition. The catalytic tests exhibited higher conversions for the AIO catalyst (47% for CH
4
and 61% for CO
2
) that can be attributed to the greater metal dispersion of this catalyst to detriment of the IWI catalyst (39% for CH
4
and 53% for CO
2
) and to the higher amount of weak basic sites provided by the AIO preparation method. Nevertheless, the IWI catalyst showed higher TOF compared to the AIO catalyst due to the weaker metal–support interaction of the former catalyst, although this is compensated by the higher number of active sites of the AIO sample. Finally, all-in-one method arises as a promising catalyst preparation technique for catalysts applied to DRM reaction since this methodology increases metal dispersion, catalyst activity, and resistance to coking.
Graphical Abstract
This research was carried out to evaluate the influence of the year and calving season on the production, composition and mozzarella cheese yield index (PKM) of Murrah water buffalos. We analyzed a ...data set of 514 lactations collected from 2004 to 2008, recorded and archived in software of a farm located in Taipu, in the eastern region of Rio Grande do Norte State, Brazil. To assess the effects of calving season, the year was divided into a rainy season (from March to August) and a dry season (from September to February). Results showed that the year influenced daily production and PKM (P<0.05). However, no effects were observed on logarithm somatic cell count (LSCC), fat, protein and total dry extract (TDE). The season had no influence on the variables analyzed and no interaction was observed between the year and the season. The season and its interactions had no effect on water buffalo performance in relation to dairy production and PKM index of mozzarella efficiency.
The increasing incidence of diabetes mellitus is becoming a serious threat to human health in various parts of the world. Studies with dairy products have shown a potential beneficial effect against ...diabetes. This experiment evaluated the supplementation of milk naturally enriched with polyunsaturated fatty acids (PUFA) and polyphenols in rats with streptozotocin-induced diabetes. Forty male 28-day-old Wistar rats were distributed in four experimental treatments of diabetic animals (streptozotocin induction) and a normal group (non-induced). Experimental treatments were: control (water), whole common milk (COM-M), milk enriched with PUFA (PUFA-M), milk enriched with PUFA and polyphenols (PUFA/P-M) through a special diet offered to dairy cows. Milk supplementation at a dose 5 mL/kg body weight was performed for 77 days, 42 days before and 35 days after diabetes induction. The COM-M supplementation increased brown fat deposits, reduced post-induction glucose levels, reduced blood fructosamine levels, and improved glucose tolerance. Milk enriched with PUFA reduced final fasting glucose, LDL levels, and improved blood antioxidant capacity. Milk enriched with PUFA and polyphenols promoted an increase in gastrocnemius muscle mass, and a reduction in mesenteric fat and LDL levels. Milk intake, with an emphasis on milk enriched with PUFA and polyphenols, attenuated the metabolic disorders of streptozotocin-induced diabetes in rats.
Many of the drugs used to fight cancer cells induce various damage causing hepatotoxic effects which are characterized by tissue changes. The aim of the study is to know the possible effects of ...salazinic acid on livers of mice exposed to Sacoma-180. The tumor was grown in the animals in ascitic form and inoculated subcutaneously in the axillary region of the mouse developing the solid tumor. Treatment with salazinic acid (25 and 50 mg/kg) and 5-Fluorouracil (20 mg/kg) started 24-hours after inoculation and was performed for 7 days. To verify these effects, the qualitative method of histological criteria investigated in liver tissue was used. It was observed that all treated groups showed an increase of pyknotic nuclei in relation to the negative control. There was an increase in steatosis in all groups compared to the negative control but there was a decrease in the groups treated with salazinic acid in the 5-Fluorouracil. There was no necrosis in the salazinic acid treated groups. However, this effect was seen in 20% of the positive control group. Therefore, it can be concluded that salazinic acid did not show hepatoprotective action on mice but demonstrated a decrease in steatosis and absence of tissue necrosis.
PDF
