•Hybrid pixel direct detector is near-ideal for electron energy loss spectroscopy.•Large dynamic range, fast frame rate, zero dark current and readout noise.•Record both inner shell loss edges and ...intense zero loss peak without saturation.•Fast elemental mapping with no noise penalty for summing many frames.•Efficient parallel acquisition with high DQE for angle resolved EELS.
We characterize a hybrid pixel direct detector and demonstrate its suitability for electron energy loss spectroscopy (EELS). The detector has a large dynamic range, narrow point spread function, detective quantum efficiency ≥ 0.8 even without single electron arrival discrimination, and it is resilient to radiation damage. It is capable of detecting ~5 × 106 electrons/pixel/second, allowing it to accommodate up to 0.8 pA per pixel and hence >100 pA EELS zero-loss peak (ZLP) without saturation, if the ZLP is spread over >125 pixels (in the non-dispersion direction). At the same time, it can reliably detect isolated single electrons in the high loss region of the spectrum. The detector uses a selectable threshold to exclude low energy events, and this results in essentially zero dark current and readout noise. Its maximum frame readout rate at 16-bit digitization is 2250 full frames per second, allowing for fast spectrum imaging. We show applications including EELS of boron nitride in which an unsaturated zero loss peak is recorded at the same time as inner shell loss edges, elemental mapping of an STO/BTO/LMSO multilayer, and efficient parallel acquisition of angle-resolved EEL spectra (S(q, ω)) of boron nitride.
BACKGROUND
Whole blood is a highly complex substance. Hemoglobin, the most abundant blood protein, can function as a flocculant; most of the other blood components exhibit poor flocculant activity. ...For the purpose of processing raw whole blood into a flocculant product, the practical value of hemoglobin purification is uncertain.
RESULTS
This study compares the flocculant performance of whole blood to that of three different semi‐purified hemoglobin preparations. The whole blood is processed to remove the plasma proteins, the solid cell components, or both. The flocculant performance of whole blood and each hemoglobin preparation is compared over wide ranges of flocculant dose and suspension pH. The clarified liquids are examined for increases in chemical oxygen demand and Kjeldahl nitrogen. Hemoglobin preparations that excluded plasma gave peak flocculation performance at approximately 30 mg solids per gram of suspended kaolin, and gave greatly reduced performance at higher doses; preparations that included plasma gave very similar peak performance, but also maintained relatively high performance at doses up to at least 200 mg g−1.
CONCLUSION
It is shown that removal of the plasma and the cell solids does not improve the flocculant performance or lessen the residual pollutants in the treated water. Published 2017. This article is a U.S. Government work and is in the public domain in the USA.
•Dilute acid hydrolysis (DAH) is an inexpensive hydrolysis method.•DAH produces large soluble fragments of MBM protein.•Solubilized MBM protein has flocculant properties.
Flocculants are substances ...that cause suspended particles to aggregate, therefore accelerating sedimentation to produce a clarified solution. They find use in a huge variety of applications including wastewater treatment, erosion control, and paper manufacture. Meat and bone meal (MBM) is a high protein by-product of meat processing. Protein extracted from MBM has been shown to have good flocculation activity, but this protein has poor solubility. Previous attempts to improve solubility through alkaline or enzymatic hydrolysis have produced small protein fragments with low flocculation activity. The objective of this project was to produce large, soluble MBM protein fragments by applying reaction conditions that are known to hydrolyze peptide bonds only at aspartic acid and asparagine residues. In this project, milled MBM was suspended in 0.03N hydrogen chloride solution, under vacuum, and incubated at 108°C. Samples were removed after 1, 2, and 4h, and the soluble and insoluble material was separated. The molar mass distribution of soluble material was examined by size exclusion chromatography (SEC), progressive solubilization of protein was measured by using a test for organic nitrogen, and flocculation activity was tested by measuring kaolin clarification effectiveness (KCE). Results showed that at all hydrolysis times, concentration of solubilized material was increased approximately 3-fold compared to the acid-free controls. Results also showed that as reaction duration increased, more MBM protein was solubilized, but average molecular weight (MW) of solute was reduced, and flocculation activity was dependent on reaction duration. The dilute acid hydrolysis (DAH) employed in this project could be a simple and inexpensive treatment that has potential to add value to MBM and provide a new source for bio-based flocculants.
BACKGROUND
The kaolin flocculant activities of bovine blood (BB) and hemoglobin (HEM) at different salt and pH values were determined. Lower limit concentration (LLC), window of application (WA), and ...degrees of clarification (DC) values for BB and HEM were determined and compared with those of the synthetic polymeric flocculants poly(diallydimethylammonium chloride) (PDADMAC), cationic polyacrylamide (PAM), and anionic PAM. BB flocculation of lignin, a bioproduct of biomass conversion to bioethanol, was demonstrated.
RESULTS
Flocculation of kaolin by BB and HEM increased at acidic pH and in the presence of NaCl. LLC values of HEM and BB were similar to LLC values of cationic and anionic PAM. LLC values of HEM and BB were 18–20‐fold higher than that of PDDMAC. WA values of BB and HEM were similar to those of PDADMAC, cationic PAM, and anionic PAM. For lignin flocculation, the ratio of LLC for BB/PDADMAC was 20–38, but the ratio of WA for BB/PDADMAC was > 3.6. For kaolin and lignin flocculation, DC values were similar for all flocculants.
CONCLUSIONS
The renewable flocculants BB and HEM rapidly settle kaolin and lignin suspensions; BB and HEM could be used in the process to separate lignin from other biomass components. Published 2014. This article is a U.S. Government work and is in the public domain in the USA
Reports of novel organic polymeric flocculants have become commonplace. The method used to test the effectiveness of these flocculants is most often the flocculation of a kaolin suspension in a jar ...test. The widely varying versions of this method that appear in the literature suffer from a range of weaknesses. The present research uses well-defined kaolin and confines testing to conditions in which the kaolin suspension is stable in the absence of a flocculant. The research examines all aspects of the conduct of the method, including clay dosing, mixing, settling time, and measurement to improve the sensitivity, reproducibility, and robustness of the method, and takes steps to avoid pitfalls that can reduce the validity of the method. Innovations include careful selection of the buffer system and instrument characteristics. Kaolin Clarification Effectiveness is introduced as a metric that gives a meaningful indication of the relative value of a novel flocculant while emphasizing the critical importance of test conditions. Together, the results form a set of recommended test conditions that should be useful for new flocculant research.
Synthetic polymeric flocculants are used extensively for wastewater remediation, soil stabilization, and reduction in water leakage from unlined canals. Sources of highly active, inexpensive, ...renewable flocculants are needed to replace synthetic flocculants. High kaolin flocculant activity was documented for bovine blood (BB) and blood plasma with several anticoagulant treatments. BB serum also had high flocculant activity. To address the hypothesis that some blood proteins have strong flocculating activity, the BB proteins were separated by SEC. Then, the major proteins of the flocculant-active fractions were separated by SDS-PAGE. Identity of the major protein components was determined by tryptic digestion and peptide analysis by MALDI TOF MS. The sequence of selected peptides was confirmed using TOF/TOF-MS/MS fragmentation. Hemoglobin dimer (subunits α and β) was identified as the major protein component of the active fraction in BB; its high flocculation activity was confirmed by testing a commercial sample of hemoglobin. In the same manner, three proteins from blood plasma (fibrinogen, γ-globulin, α-2-macroglobulin) were found to be highly active flocculants, but bovine serum albumin, α-globulin, and β-globulin were not flocculants. On a mass basis, hemoglobin, γ-globulin, α-2-macroglobulin were as effective as anionic polyacrylamide (PAM), a widely used synthetic flocculant. The blood proteins acted faster than PAM, and unlike PAM, the blood proteins flocculants did not require calcium salts for their activity.
A previous study reported conditions that hydrolyze meat and bone meal (MBM) protein in a site-specific manner, transforming insoluble MBM protein into large, soluble protein fragments with good ...flocculant functionality. It is not clear, however, that this phenomenon can be adapted for industrial-scale processing of MBM at reasonable expense. The present study examines whether the desirable characteristics of the reaction product are retained when hydrolysis is conducted using much higher MBM concentration, MBM with relatively large solid particles, and in the presence of fat and bone. The results showed that bone mineral depressed the conversion rate progressively as the MBM concentration increased. An increase in acid concentration reversed the rate depression, and good conversion rates were achieved for up to 200 g of substrate per liter. Particle size and fat showed no consistent effect on the conversion rate. The reaction was shown to retain its site specificity under all conditions tested. Higher MBM concentration and longer reaction times both favored the production of relatively large peptides (MW >5 kDa). Finally, the protein hydrolysate was shown to retain flocculant properties comparable to those of water-extracted MBM protein. These results indicate that the reaction under consideration could be used to convert MBM protein into a more valuable functional product.
Rendered animal proteins are well suited for animal nutrition applications, but the market is maturing, and there is a need to develop new uses for these products. The objective of this study is to ...explore the possibility of using animal proteins as a nutrient source for microbial production of omega-3 polyunsaturated fatty acids by the microalga Schizochytrium limacinum and the fungus Pythium irregulare. To be absorbed by the microorganisms, the proteins needed to be hydrolyzed into small peptides and free amino acids. The utility of the protein hydrolysates for microorganisms depended on the hydrolysis method used and the type of microorganism. The enzymatic hydrolysates supported better cell growth performance than the alkali hydrolysates did. P. irregulare displayed better overall growth performance on the experimental hydrolysates compared to S. limacinum. When P. irregulare was grown in medium containing 10 g/L enzymatic hydrolysate derived from meat and bone meal or feather meal, the performance of cell growth, lipid synthesis, and omega-3 fatty acid production was comparable to the that of culture using commercial yeast extract. The fungal biomass derived from the animal proteins had 26–29% lipid, 32–34% protein, 34–39% carbohydrate, and <2% ash content. The results show that it is possible to develop a nonfeed application for rendered animal protein by hydrolysis of the protein and feeding to industrial microorganisms which can produce omega-3 fatty acids for making omega-3-fortified foods or feeds.
•Continuous ultrasonic processing can effectively lyse chicken blood cells in 300ms.•Flocculant activity is not degraded by exposure to ultrasound.•Electricity costs are estimated at $0.82 per 1000L ...blood.
Hemoglobin from chicken blood has been shown to be a good substitute for synthetic polymeric flocculants. One stage of processing the blood entails lysis of the cells to release the hemoglobin; in the present study, the use of ultrasonic processing at this stage is investigated. Washed chicken blood cells are suspended in buffer and run continuously through a chamber attached to an ultrasonic probe. Calorimetry is used to measure acoustic power input to the liquid. Ultrasonic cell lysis is tested using chamber residence times of 75–300ms, and the equipment's entire range of power inputs. The hemoglobin release kinetic parameters are determined and it is shown that above a particular level, increasing power input can actually result in a decreased rate constant. Ultrasonic processing can damage proteins, so reduction of hemoglobin's flocculant activity is considered. Using a sensitive assay involving suspensions of kaolin clay, no effect of ultrasonic processing on hemoglobin flocculant activity is detected. Although the conversion of electrical power to acoustic power is inefficient, the electric power required to release greater than 90% of the hemoglobin is shown to be minimal.
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