Cytochrome P450 (CYP) bioreactors play a major role in establishing the practical use of this enzyme family in academia and industry. The current demand for enzymatic hydroxylations of unactivated carbons in the parmaceutical industry includes the preparation of drug metabolites and various hydroxylated synthetic precursors as well as the enzyme mediated lead diversification and natural product synthesis, most of which require multigram scale synthesis. To date, the large scale application of CYPs in the synthesis of oxygenated compounds is limited by many challenges. This review describes relevant examples of CYP oxidations and also presents the strategies available to overcome such challenges. At present, P450 catalyzed reactions can only be performed at substrate concentrations ranging from 1-25 mM, unlike other biocatalytic redox reactions like ketone reductases, typically performed at substrate loads greater than 500 mM. The emergence of powerful expression methods and a large number of CYP mutants developed for specific applications holds the promise for future industrial applications. The search for higher volumetric productivities is however a task that needs to be addressed not only through the use of protein engineering as the primary tool but significant emphasis needs to be placed on process development through exploring multiple operating schemes, optimizing reaction media and modifying microbial strains needed for heterologous expression.
The reuse of waste in civil construction brings environmental and economic benefits. However, for these to be used in concrete, it is necessary a previous evaluation of their physical and chemical characteristics. Thus, this study aimed to characterize and analyze the waste foundry exhaust sand (WFES) for use in self-compacting concrete (SCC). Foundry exhaust sand originates from the manufacturing process of sand molds and during demolding of metal parts. It is a fine sand rich in silica in the form of quartz collected by baghouse filter. Characterization of WFES was conducted through laser granulometry, scanning electron microscopy (SEM) in the energy dispersive spectroscopy (EDS) mode, X-ray diffraction (XRD), X-ray fluorescence (XRF), Fourier transform infrared spectroscopy (FTIR), thermogravimetry (TG) and derivative thermogravimetry (DTG) techniques. The waste was classified as non-hazardous and non-inert, with physical and chemical properties suitable for use in SCC composition, as fine aggregate or mineral addition. Five mixtures of SCC were developed, in order to determine the waste influence in both fresh and hardened concrete. The properties in the fresh state were reached. There was an increase in compressive strength and sulfate resistance, a decrease in water absorption of self-compacting concrete by incorporating WFES as 30% replacement.
Seas and oceans offer great potential as a widely available source of clean and renewable energy near high energy consumption centers. This source of energy is a valuable option in the energy transition and in energy matrix decarbonization. Wave energy and an oscillating water column (OWC) device stand out as the types of ocean energy with the most potential. An onshore OWC requires locations with rocky outcrops and steeper slopes as the device needs to be physically installed and has lower energy dissipation due to friction with the seabed. However, Brazil has approximately 7490 km of coastlines, with various shoreline geometries and geomorphologies, some of which are very suitable for OWC implementation. Some authors have estimated that the Brazilian coast has a total potential of 114 GW, distributed between wave and tidal energy, with a great possibility of contributing to global decarbonization efforts. This study aimed to identify and quantify the potential of locations suitable for implementing wave energy farms equipped with onshore OWC. For this, a prospect was carried out using the georeferencing software QGIS, resulting in a georeferenced map with a dataset of 319 locations, and determining a power capacity of exploitation of 9.84 GW and an estimated energy of 83,689 GWh/year in ten of the seventeen coastal states. This energy corresponds to twice the energy consumption of the state of Rio de Janeiro, which has a population of approximately 17.5 million people. If the same amount of wave energy as gas-fired thermal generation energy were to be consumed, the use of wave energy would reduce emissions by approximately 44.52 million tons of CO2 annually. This result suggests that wave energy generation should be included in future studies on the expansion of Brazilian electric systems as an accelerating factor in the energy transition.
1 September 2018 in Revista Brasileira de Engenharia Agrícola E Ambiental
This study presents an analysis of the abrasive effects of sediments from the bed of the Acre River, Brazil, on the wear of three different ferrous materials employed in the manufacture of impellers of centrifuge pumps used to catch raw water. In order to evaluate the abrasive wear and specific wear coefficient (k) as a function of sediment concentration, tests were conducted in samples of SAE 8620 steel, nodular cast iron and gray cast iron by using a rotary-ball abrasion meter. These tests employed abrasive slurry with concentration of 1, 2, 3, 5 and 10 g L-1 of sediments in distilled water. The volume of worn material as a function of the relative velocity of water flow in relation to the impeller blades was mathematically estimated. The experimental results showed that: i) The semi-angular and semi-rounded shapes of the sediments from the Acre River produced evidence of micro-grooving and plastic deformation in the three metallic alloys; ii) SAE 8620 steel showed higher resistance to abrasive wear than samples of gray and nodular cast iron; iii) the increase in the volume of worn material due to increment in sediment concentration and the relative velocity of the mixture (water + sediment) to the rotor pads.
Pumping systems, especially those used in the water supply sector and in industrial and hydroelectric facilities, are commonly infested by the golden mussel. This causes an increase in maintenance operations (e.g., system shutdowns for cleaning) that can generate an increased energy cost. The geographical expansion of the golden mussel in Latin America presents an economic risk, not only to the ecosystem in general, but also to the energy sector. The imminence of its spread in the Amazon region, one of the main river basins in South America, is cause for concern with regard to the problems that bioinvasion of this species can cause. Given the absence of studies on the loss of energy efficiency in pumping systems impacted by the golden mussel, this study proposes a methodology to estimate the increase in energy consumption and costs of pumping under such bioinfestation. For the standardization of the methodology and development of mathematical calculations (both novel and improved equations), data from the literature (the growth of the golden mussel as a function of infestation time) and an analysis of the dimensions (length and height) of a sample of mussels available in the laboratory were considered. These data were used to calculate the roughness generated by the mussel infestation in the pumping suction and discharger pipe, which was necessary to determine the loss of energy efficiency (load loss, power consumption, and cost of pumping) resulting from the increase in energy consumption for pumping. This methodology was applied to a pumping station representative of the Brazilian Amazon as a case study. The results show an average increase in economic indicators (consumption and cost of pumping) after the system undergoes bioinfestation. This total increase corresponded to 19% and 44% in the first and second years, respectively, achieving a stabilization of the increase in the cost of pumping at 46%, in the 30 months of operation. Our results demonstrate the pioneering nature of the proposal, since these are the first quantitative data on the energy efficiency of pumping systems associated with bioinfestation by the golden mussel. These results can also be used to estimate the increase in costs caused by golden mussel bioinfestation in the raw water pumping systems of other facilities.