Volumetric Yield Research Articles

Wheat straw/HDPE co-reaction synergy and enriched production of aromatics and light olefins via catalytic co-pyrolysis over Mn, Ni, and Zn metal modified HZSM-5

The co-reaction synergy of wheat straw (WS) and high-density polyethylene (HDPE) plastic waste with varying mass ratios were evaluated at 550 °C in a fixed bed pyrolyzer reactor. Ex-situ catalytic co-pyrolysis of WS and HDPE feed mix (3:1) at a high feed to catalyst ratio (10:1) was performed over Mn, Ni, and Zn (1, 5, and 10 wt%) metal-modified HZSM-5 at 550 °C to study the effect of metal promotors variations on the production of aromatics and light olefins. The prepared catalysts were characterized by employing XRD, N2 physisorption, NH3-TPD, H2-TPR, and UV-Vis analytical techniques. The results obtained in the present work indicated that 1%-Zn modified HZSM-5 produced a more relative proportion of aromatics (25.12%) in the co-pyrolysis oil organic phase, followed by 5% Ni and 5%-Zn-loaded HZSM-5 at 16.22% and 15.76% respectively. Furthermore, 5% Ni-HZSM-5 has shown higher deoxygenation ability (58.43%) in reducing the oxygenates formed, followed by 5% Mn (40.96%) and 1% Zn (35.37%) respectively. While, 5% Mn-HZSM-5 generated pyrolytic gases with higher volumetric compositions of (C2-C4) light olefins at 15.84%, followed by 1% Mn (13.97%) and 10% Ni (13.61%) respectively and these volumetric yields were strongly correlated with intermediate acidity of catalysts. The physical properties (e.g. HHV ~ 41–43 MJ/kg) of the resultant organic fraction of catalytic co-pyrolysis bio-oil are almost analogous to conventional fuels such as diesel and light fuel oil (LFO). Additionally, the resultant catalytic pyrolytic gases possessed excellent calorific value (LHV ~ 30–31 MJ/Nm3) and are comparable to natural gas. Overall, the present study has successfully demonstrated the promising nature of the catalytic co-pyrolysis process for the conversion of biomass and waste plastic into useful chemicals and fuels.

Effective metal encapsulation of carbon nanotubes by micro-current electrochemical deposition

The inner cavities of carbon nanotubes (CNTs) have attracted much attention for one-dimensional structures and their unique properties. The encapsulation of hetero-structures into CNTs is the foundation for potential applications. Solution and vapor methods have been well adopted for CNTs encapsulations. The solution method is restricted to its low encapsulation yield. Only chemicals with relatively low sublimation points under low pressures and low activity have been demonstrated to be encapsulated into the inner cavities of CNTs by vapor methods. No effective encapsulation method for most metals has been explored so far. Now, a widely applicable metal encapsulation method, micro-current electrochemical deposition, has been demonstrated to encapsulate lithium, sodium and potassium metals into CNTs with high yield. The volumetric encapsulation yields of lithium, sodium and potassium metal have been demonstrated to be higher than 65%.

Chlorella potential to purify domestic garbage leachate for biomass production and community structure responses of wastewater-borne bacteria

The microalgae growth, accumulation of high value-added substances of Chlorella sp. HQ and its water purification potential during cultivation in diluted domestic garbage leachate (DGL) were investigated and changes in the structure of wastewater-borne bacteria community were also analyzed. Results showed that the highest density of Chlorella (1.70 × 108 cells/mL) was obtained in DGL diluted 5 times with rural sewage, the contents of protein and sugar in microalgae cells were 36.0 % and 45.6 %, Moreover, energy volumetric yield reached 48.54 kJ/L. After 15 d of microalgae treatment, the removal rates of total nitrogen (TN), ammonia nitrogen (NH4+-N), chemical oxygen demand (COD), total phosphorus (TP) of diluted DGL were 88.2 %, 97.3 %, 94.9 %, and 95.2 %, respectively, with the fluorescence peaks of humic-like organic matter shifting to longer wavelengths. Moreover, high-throughput sequencing of wastewater-borne bacteria showed that microalgae growth could promote the enrichment of denitrifying polyphosphate accumulating bacteria, which suggests that wastewater-borne bacteria and Chlorella may form a cooperative mode to achieve water purification.

Coupling of wastewater treatment and microalgae products recovery: Effect of phosphorus components on the biochemical composition and phosphorus absorption of Chlorella pyrenoidosa

Microalgae cultivation with wastewater provides a promising pathway in wastewater treatment and microalgae products recovery. Different forms and concentrations of phosphorus were used to understand the effect of complex phosphorus components in wastewater on microalgae biochemical composition and phosphorus absorption. The results showed that various phosphorus forms could be absorbed and utilized, and the higher biomass production was obtained with the combination of K2HPO4 and ATP than that of Na5P3O10 and G6P. C. pyrenoidosa could uptake and storage luxury phosphorus with adequate phosphorus supply. Increasing phosphorus concentrations had a positive effect on carbohydrate and protein contents, while had a negative effect on biomass production and lipid contents. The maximum total volumetric energy yield of C. pyrenoidosa was obtained with the combination of K2HPO4 and ATP under 10 mgP/L. The results could further guide the coupling of wastewater phosphorus recovery and microalgae biofuels production.

The effect of the addition of flour from the root tubers of sweet potato varieties (<i>Ipomoea batatas</i> Lam.) with colored pulp on the baking and consumer qualities of wheat bread

Relevance. Currently, there is an increasing interest in nutritional supplements of natural origin. One of the crops that can be used for this is sweet potato. The inclusion of flour from dried sweet potato tubers with colored pulp in the recipe of wheat bread can contribute to its enrichment with vitamins and antioxidants. Therefore, the study of the suitability of sweet potato tubers obtained in the conditions of the Non-Chernozem Zone for use as an additive in the production of bread is an urgent task.Material and methods. The article presents the results of a comparative study of the appearance and taste of bread with the addition of various amounts of powder from root tubers with colored pulp of two varieties of sweet potato (Purple 1 - anthocyanin and Beauregard – carotenoids).Results. It has been established that sweet potato root tubers grown in the conditions of the Central region of the Non-Chernozem zone are suitable for use as a natural food additive to wheat bread. The positive effect of preliminary steaming of tubers before drying on the volumetric yield of bread and the color of its crumb was revealed. The studied varieties of sweet potato differed significantly in the yield of air-dry powder - the Purple 1 variety had an advantage over the Beauregard variety. Bread with additions of 5% and 10% of Purple 1 tuber powder was characterized by the best appearance and taste. The Beauregard variety had a high sugar content, which negatively affected the consumer advantages of bread with its additives.

Microbial Surfactants: Bright Prospects for Innovation, New Product Categories, and Commercialization

Microbial Surfactants: Bright Prospects for Innovation, New Product Categories, and Commercialization

Enhanced lactic acid production with indigenous microbiota from date pulp waste and keratin protein hydrolysate from chicken feather waste

A substantial amount of keratin, a key protein with excellent material-forming properties, can be sustainably extracted from chicken feathers, which are commonly discarded in the poultry industry. The keratin protein found in chicken feathers can serve as a nitrogen source and a pH regulator for microbes. In this study, the use of indigenous bacteria and extracted keratin protein hydrolysate from chicken feathers as a nitrogen source improved lactic acid production from date pulp waste by fermentation. After six days of optimal dark fermentation time at pH 6, the maximum concentration of L-lactic acid (46.2 g/L) was obtained with keratin protein hydrolysate and date pulp waste substrate. Under the same conditions, the value was 2.12 times higher than that of the date pulp waste substrate (21.7 g/L) without the addition of keratin protein hydrolysate. Under optimal conditions, volumetric lactic acid productivity and yield were 7.7 g/L/day and 0.3 g/g substrate, respectively. Keratin protein hydrolysate proved to be the most effective neutralizing agent for L-lactic acid production at a concentration of 6 g/L. The combination of keratin protein hydrolysate and date pulp waste was studied for the first time as a substrate for lactic acid production. Keratin protein hydrolysate was found to buffer pH changes during fermentation. Poultry and plant by-products are usually available in agriculturally challenged areas. Therefore, this study provides an excellent opportunity to recycle waste and improve the overall circular economy of such agro-industrial complexes.

Quasistatic anisotropic induced behaviour of a tatb-based plastic-bonded explosive

The constitutive law of a plastic-bonded explosive (PBX) based on TATB crystals is studied in the quasistatic loading range. The experimental data highlight a viscoelastic behaviour with damage, and an anisotropy induced by plastic flow. The existing models for PBXs being not appropriate, a constitutive law accounting for the observed mechanisms is proposed. The linear viscoelasticity is integrated in a microplane model describing an effective anisotropic damage. A multilayer viscoplasticity is used to yield a non-linear kinematic hardening. A von Mises yield criterion is defined on each surface and a dilatancy function describes the volumetric plastic yield. This law is implemented in the Abaqus/Standard finite element code in the form of a UMAT subroutine. The model is calibrated on ten tests. The simulations performed to compare the model to each experimental test correctly reproduce the behaviour of the studied explosive composition.

A priori error analysis of shape derivatives of linear functionals in structural topology optimization

We provide theoretical analyses and numerical comparisons of boundary-based and volumetric shape derivative expressions of linear objective functionals encountered in topology optimization of linear elastic structures. The two expressions yield identical results if the domain is smooth and the governing equation is solved exactly; however, the finite element approximation of the expressions for less regular domains yield different results. We first review the two expressions to show that the volumetric shape derivative places weaker regularity requirements, which, unlike the requirements for boundary-based shape derivatives, are satisfied in most finite element approximations. We then analyze the error in the degree-k polynomial finite element approximations of the two expressions; we show that, for sufficiently regular problems, the boundary-based and volumetric shape derivatives provide kth and 2k-th order accurate approximations, respectively, of the true shape derivative. We finally assess, through numerical examples, the practical implications of using the volumetric vs boundary-based shape derivatives in topology optimization problems; we demonstrate that methods based on the volumetric shape derivative yield more robust solutions to topology optimization problems.

Microbial | electrochemical CO2 reduction: To integrate or not to integrate?

Microbial | electrochemical CO2 reduction: To integrate or not to integrate?

Strategic Development of Aurantiochytrium sp. Mutants With Superior Oxidative Stress Tolerance and Glucose-6-Phosphate Dehydrogenase Activity for Enhanced DHA Production Through Plasma Mutagenesis Coupled With Chemical Screening.

Thraustochytrids, such as Aurantiochytrium and Schizochytrium, have been shown as a promising sustainable alternative to fish oil due to its ability to accumulate a high level of docosahexaenoic acid (DHA) from its total fatty acids. However, the low DHA volumetric yield by most of the wild type (WT) strain of thraustochytrids which probably be caused by the low oxidative stress tolerance as well as a limited supply of key precursors for DHA biosynthesis has restricted its application for industrial application. Thus, to enhance the DHA production, we aimed to generate Aurantiochytrium SW1 mutant with high tolerance toward oxidative stress and high glucose-6 phosphate dehydrogenase (G6PDH) activities through strategic plasma mutagenesis coupled with chemical screening. The WT strain (Aurantiochytrium sp. SW1) was initially exposed to plasma radiation and was further challenged with zeocin and polydatin, generating a mutant (YHPM1) with a 30, 65, and 80% higher overall biomass, lipid, and DHA production in comparison with the parental strains, respectively. Further analysis showed that the superior growth, lipid, and DHA biosynthesis of the YHMP1 were attributed not only to the higher G6PDH and enzymes involved in the oxidative defense such as superoxide dismutase (SOD) and catalase (CAT) but also to other key metabolic enzymes involved in lipid biosynthesis. This study provides an effective approach in developing the Aurantiochytrium sp. mutant with superior DHA production capacity that has the potential for industrial applications.

High Cell Density Cultivation Process for the Expression of Botulinum Neurotoxin a Receptor Binding Domain.

The receptor-binding domain of botulinum neurotoxin (HC fragment), is a promising botulism vaccine candidate. In the current study, fermentation strategies were evaluated to upscale HC fragment expression. A simple translation of the growth conditions from shake flasks to a batch fermentation process resulted in limited culture growth and protein expression (OD of 11 and volumetric protein yields of 123 mg/L). Conducting fed-batch fermentation with rich media and continuous nutrient supplementation significantly improved culture growth (OD of 40.3) and protein expression (1093 mg/L). A further increase in HC fragment yield was achieved by high cell density cultivation (HCDC). The bacterium was grown in a defined medium and with a combined bolus/continuous feed of nutrients to maintain desired oxygen levels and prevent acetate accumulation. The final OD of the process was 260, and the volumetric yield of the HC fragment was 2065 mg/L, which reflects improvement by an order of magnitude. Purified HC fragments, produced by HCDC, exhibited typical biochemical and protective characteristics in mice. Taken together, the advancements achieved in this study promote large-scale production of the HC fragment in E. coli for use in anti-botulism vaccines.

Addition of biomass ash as a promising strategy for high-value biohythane production from the organic fraction of municipal solid waste

In this work, the effect of adding ash from combustion of six locally available biomass types, namely common reed (Phragmites australis), corn stover, eucalyptus sawdust, hazelnut shells, pine chips, and rice husks at different concentrations (2.5, 5, 10, and 20 g/L) on H2 production from the organic fraction of municipal solid waste (OFMSW) was first investigated through batch experiments. The maximum cumulative H2 production of 1124 ± 3.21 mL was achieved using 5 g/L of rice husk ash (RHA), increasing by 644% compared to the control. Then, in a semi-continuous two-stage biohythane production process, the first reactor dedicated to H2 production was supplemented with 5 g/L of RHA and its performance was evaluated at three HRTs (3, 2, and 1 day). The results showed that the highest steady-state volumetric H2 production rate (554 ± 5.48 mL/L/d) and H2 yield (184.7 ± 1.83 mL/g-VSadded) were obtained at 2-day HRT. In the subsequent CH4 production stage, of the three HRTs tested (12, 8, and 4 days), the 12-day HRT resulted in a maximum volumetric CH4 production rate and CH4 yield of 321 ± 2.39 mL/L/d and 727.2 ± 5.46 mL/g-VSadded, respectively, under steady-state conditions. Throughout both stages, the pH remained within a suitable range without the addition of any commercial reagents. The overall energy yield of the two-stage process was found to be 31.2 kJ/g-VSadded, which corresponded to a total COD removal efficiency of 96%. Moreover, the composition of biohythane (H2 + CH4) obtained met the standards of a clean hythane fuel.

Combination of sodium butyrate and decitabine promotes transgene expression in CHO cells via apoptosis inhibition

Chinese hamster ovary (CHO) cells are currently the most widely used host cells for production of recombinant therapeutic proteins (RTPs). Small-molecule additives related to cell cycle apoptosis and autophagy regulation have been used to promote RTP production. By combining two small-molecule additives, positive synergistic effects on transgene expression were observed in CHO cells. In the present study, six small-molecule additives were used, including hydrocinnamic acid (HCA), sodium butyrate (NaB), lithium acetate (LiAc), sodium succinate dibasic hexahydrate (SDH), decitabine (DAC), and sodium propionate (SP). Experiments to test the effects of their pairwise combinations on two different recombinant CHO cell lines (rCHO) were designed using Design-Expert 12.0. Different effects of various pairs of small molecules on apoptosis- and autophagy-related protein expression were observed in the rCHOs. The results showed that compared to the control culture, NaB alone increased the volumetric yield and specific productivity (Qp) by 166% and 143%, respectively. The volumetric yield and Qp of NaB combined with DAC (Cg1)-treated cells increased by 178% and 212%, respectively. Cg1 selectively blocked the cells in the G0/G1 cell cycle stage. The relative expression levels of B-cell lymphoma 2 (Bcl-2), Beclin 1, and microtubule-associated protein light chain 3 (LC3B) in Cg1-treated CHO cells were significantly increased, while relative levels of cleaved caspase-3 expression were significantly decreased. In conclusion, Cg1 had the most obvious effect on RTP production and Qp in CHO cells, suggesting the Cg1 combination of small molecules may be used to improve the expression of recombinant protein in CHO cells.

A statistical approach to boost soluble expression of E. coli-derived virus-like particles in shake-flask cultivation

Hepatitis B core virus-like particles (HBc-VLP) have been widely used as carrier platforms to present an epitope of interest. Escherichia coli expression system is cost effective and produces high yields of recombinant protein. However major drawbacks include difficulties in obtaining soluble expression and tendency to form inclusion bodies. To boost solubility of proteins during expression of E. coli-derived HBc-VLPs carrying EBNA1 epitope, a statistical approach involving fractional factorial design and response surface methodology was used. For the first time, this approach was applied to quantitatively determine the impact of key parameters in shake-flask cultivation. Expression conditions including post-induction temperature and shaker-speed, and cell density at induction were optimized. Based on native agarose gel electrophoresis, optimized soluble protein cellular yield was 210.5 mg g−1 dry cell mass and volumetric yield was 272 mg L−1 of culture media. Findings highlight: 1) the significant interaction between post-induction temperature and shaker-speed on production, and; 2) sufficient oxygen level is required during induction. It is concluded that this statistical approach can be practically applied to optimize expression of HBc-VLP in shake-flask cultivation, and to determine key parameters for large-scale productions.

Biofuel recovery from microalgae biomass grown in dairy wastewater treated with activated sludge: The next step in sustainable production

Microalgae biofuel could be the next step in avoiding the excessive use of fossil fuels and reducing negative impacts on the environment. In the present study, two species of microalgae (Scenedesmus obliquus and Chlorella vulgaris) were used for biomass production, grown in dairy wastewater treated by activated sludge systems. The photobioreactors were operated in batch and in continuous mode. The dry biomass produced was in the range of 2.30 to 3.10 g L−1. The highest volumetric yields for lipids and carbohydrates were 0.068 and 0.114 g L−1 day−1. Maximum CO2 biofixation (750 mg L−1 day−1) was obtained in continuous mode. The maximum values for lipids (21%) and carbohydrates (39%) were recorded in the batch process with species Scenedesmus obliquus. In all of the experiments, the Linolenic acid concentration (C18:3) was greater than 12%, achieving satisfactory oxidative stability and good quality. Projected biofuel production could vary between 4,863,708 kg and 9,246,456 kg year−1 if all the dairy wastewater produced in Brazil were used for this purpose. Two hectares would be needed to produce 24,99 × 109 L year−1 of microalgae bioethanol, a far lower value than used in cultivating sugar cane. If all dairy wastewater generated annually in Brazil were used to produce microalgae biomass, it would be possible to obtain approximately 30,609 to 53,647 barrels of biodiesel per year. These data show that only by using dairy wastewater would biofuels be produced to replace 17% to 40% of the fossil fuels currently used in Brazil.

GbpA as a secretion and affinity purification tag for an antimicrobial peptide produced in Vibrio natriegens

BackgroundVibrio natriegens is a Gram-negative bacterium that offers a greater metabolic capacity than Escherichia coli for the production of recombinant proteins. This potential includes a low minimum doubling time of 7 min and a high maximum glucose uptake rate of 3.9 g*g−1*h−1. We therefore tested the ability of V. natriegens to produce the insect metalloprotease inhibitor (IMPI), an antimicrobial peptide, fused to the glucosamine-binding protein A (GbpA) secretion/purification tag, using the Vmax Express system. ResultsThe IMPI-GbpA fusion protein was secreted into the medium and could be purified directly from the fermentation supernatant by affinity chromatography, including on-column digestion with thrombin. We also modified the GbpA tag by deleting the second and third domains, which reduced the size of the tag while maintaining its functionality. This modification also increased the IMPI yield. ConclusionsThe use of V. natriegens as an expression platform and GbpA for protein secretion and purification facilitates the inexpensive production of antimicrobial peptides. Our process achieved a higher volumetric yield than earlier attempts to produce recombinant IMPI in E. coli. However, the accumulation of IMPI causes V. natriegens growth arrest before the carbon source is depleted, suggesting it may be possible to achieve even greater productivity by further process optimization.How to cite: Schwarz S, Gerlach D, Fan R, et al. GbpA as a secretion and affinity purification tag for an antimicrobial peptide produced in Vibrio natriegens. Electron J Biotechnol 2022;56. https://doi.org/10.1016/j.ejbt.2022.01.003.

Sodium Alginate and Chitosan as Components Modifying the Properties of Inulin Hydrogels.

The aim of the study was to investigate the influence of addition of sodium alginate (SA) and chitosan (CH) on the properties of inulin hydrogels. Inulin hydrogels (20 g/100 g) containing various additions (0.0, 0.1, 0.3, and 0.5 g/100 g) of SA and CH were produced. The hydrogels’ properties were assessed based on the volumetric gel index, microstructure, yield stress, texture, stability, and color parameters. According to the findings, the inclusion of these polysaccharides had no influence on the gelation ability of the inulin solution. The physical properties of the hydrogels containing SA or CH differed from hydrogels containing only inulin (INU). The obtained microstructural pictures revealed that the addition of SA and CH resulted in the formation of hydrogels with a more compact, smooth, and cohesive structure. Consequently, they had higher yield stress, strength, and spreadability values than INU hydrogels. The addition of chitosan in comparison with sodium alginate also had a greater effect in strengthening the structure of hydrogels, especially at the level of 0.5 g/100 g. For example, the addition of this amount of SA increased the yield stress on average from 195.0 Pa (INU) to 493.6 Pa, while the addition of CH increased it to 745.3 Pa. In the case of the strength parameter, the addition of SA increased the force from 0.24 N (INU) to 0.42 N and the addition of CH increased it to 1.29 N. In the case of spreadability this increase was from 2.89 N * s (INU) to 3.44 N * s (SA) and to 6.16 N * s (CH). Chitosan also caused an increase in the stability of inulin hydrogels, whereas such an effect was not observed with the addition of sodium alginate. The gels with the addition of SA and CH also had significantly different values of color parameters. Inulin–alginate hydrogels were characterized by higher values of the color parameter a *, lower values of the color parameter b *, and in most concentrations higher values of the color parameter L * compared to inulin–chitosan hydrogels. Based on the collected data, it can therefore be concluded that through the addition of sodium alginate and chitosan, there is a possibility to modify the properties of inulin hydrogels and, consequently, to better adapt them to the characteristics of the pro-health food products in which they will be used.

Effectively Improve the Astaxanthin Production by Combined Additives Regulating Different Metabolic Nodes in Phaffia rhodozyma.

Astaxanthin is an important natural resource that is widely found in marine environments. Metabolic regulation is an effective method for improving astaxanthin production in Phaffia rhodozyma. Most studies have focused on single regulators, which have limited effects. In this study, 16 metabolic regulators were screened to improve astaxanthin production in high-yield and wild-type strains. Fluconazol and glutamic acid increased astaxanthin volumetric yield in MVP14 by 25.8 and 30.9%, respectively, while ethanol increased astaxanthin volumetric yield in DSM626, 29.3%. Furthermore, six additives that inhibit the competing pathways and promote the main pathway for astaxanthin synthesis were selected for combination treatment. We found that the optimal combination was penicillin, ethanol, triclosan, and fluconazol, which increased astaxanthin cell yield by 51%. Therefore, we suggest that simultaneously promoting the master pathways (mevalonate) and inhibiting competing pathways (fatty acid synthesis and ergosterol) is the best strategy to improve astaxanthin cell yield. Moreover, regulators of the biomass pathway should be avoided to improve cell yield. This study provides a technical basis for the utilisation of astaxanthin in P. rhodozyma.

Evaluation of interface shear transfer strength of steel fiber‐reinforced concrete based on artificial neural network and regression method

AbstractTransfer of shear strength across the concrete‐to‐concrete interface is important to the strength of reinforcement concrete structures and is extensively existing in repairing and strengthening existing reinforced concrete members, the connections between prefabricated members and the connection joints between concrete sections cast in situ. Steel fibers improve the mechanical properties of concrete and steel fiber‐reinforced concrete (SFRC) has been universally applied as the repaired materials and the connection materials in reinforced concrete structures. The aim of this paper is to evaluate the interface shear transfer (IST) strength of SFRC. One hundred twenty‐seven‐group experimental results are collected from previous studies to establish a reliable database, which the investigated parameters include the compressive strength of concrete, the diameter, length and volume friction of steel fibers, and the volumetric ratio and yield strength of shear reinforcement. Based on the established database, an artificial neural network (ANN) model is developed and the parameters sensitive is analyzed based on the proposed ANN model. Based on the parametric sensitive analysis, the linear regression model is established to evaluate the IST strength of SFRC, which is applied to evaluate the design of the concrete‐to‐concrete connections.