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1.
Methods Mol Biol ; 2829: 195-202, 2024.
Article in English | MEDLINE | ID: mdl-38951335

ABSTRACT

The Baculovirus Expression Vector System (BEVS) has revolutionized the field of recombinant protein expression by enabling efficient and high yield production. The platform offers many advantages including manufacturing speed, flexible design, and scalability. In this chapter, we describe the methods including strategies and considerations to successfully optimize and scale-up using BEVS as a tool for production (Fig. 1). As an illustrative case study, we present an example focused on the production of a viral glycoprotein.


Subject(s)
Baculoviridae , Genetic Vectors , Recombinant Proteins , Baculoviridae/genetics , Recombinant Proteins/genetics , Recombinant Proteins/biosynthesis , Genetic Vectors/genetics , Animals , Humans , Sf9 Cells
2.
Water Sci Technol ; 89(10): 2796-2811, 2024 May.
Article in English | MEDLINE | ID: mdl-38822615

ABSTRACT

Anaerobic treatment of oily substrate, known as grease trap waste (GTW), was investigated for its practicability via continuous stirred tank reactor (CSTR) at different operating conditions and selected recovery strategies of feeding frequency efficacy. This study determine the performance of feeding frequency efficacy, namely feeding every 24 hours (R24H) and feeding every 12 hours (R12H). Under organic loading rate (OLR) of 2.2 gCOD/L.day, R12H exhibited methane composition of 57%, methane production rate of 0.27 LCH4/L.day, and methane yield of 0.14 LCH4/gCODremoved. At the same OLR, R24H recorded methane composition of 60%, methane production rate of 0.29 LCH4/L.day and similar methane yield as R12H. Findings indicated that R24H showed performance comparable to that of R12H. Given minor variation observed in performance, it is recommended that plant operators may consider scheduling two feedings per day for low loading conditions and switch to one feeding per day for higher loading conditions. This strategy is designed to balance the system and prevent shock loads, which could lead to plant shutdowns. This mechanism will induce their conversion to volatile fatty acids (VFAs); thus, reducing the risk of acid accumulation and pH drops, which could inhibit methanogens to produce methane, especially for oily substrate.


Subject(s)
Biofuels , Bioreactors , Methane , Anaerobiosis , Methane/metabolism , Waste Disposal, Fluid/methods
3.
Microb Cell Fact ; 23(1): 131, 2024 May 06.
Article in English | MEDLINE | ID: mdl-38711081

ABSTRACT

BACKGROUND: Komagataella phaffii (Pichia pastoris) has emerged as a common and robust biotechnological platform organism, to produce recombinant proteins and other bioproducts of commercial interest. Key advantage of K. phaffii is the secretion of recombinant proteins, coupled with a low host protein secretion. This facilitates downstream processing, resulting in high purity of the target protein. However, a significant but often overlooked aspect is the presence of an unknown polysaccharide impurity in the supernatant. Surprisingly, this impurity has received limited attention in the literature, and its presence and quantification are rarely addressed. RESULTS: This study aims to quantify this exopolysaccharide in high cell density recombinant protein production processes and identify its origin. In stirred tank fed-batch fermentations with a maximal cell dry weight of 155 g/L, the polysaccharide concentration in the supernatant can reach up to 8.7 g/L. This level is similar to the achievable target protein concentration. Importantly, the results demonstrate that exopolysaccharide production is independent of the substrate and the protein production process itself. Instead, it is directly correlated with biomass formation and proportional to cell dry weight. Cell lysis can confidently be ruled out as the source of this exopolysaccharide in the culture medium. Furthermore, the polysaccharide secretion can be linked to a mutation in the HOC1 gene, featured by all derivatives of strain NRRL Y-11430, leading to a characteristic thinner cell wall. CONCLUSIONS: This research sheds light on a previously disregarded aspect of K. phaffii fermentations, emphasizing the importance of monitoring and addressing the exopolysaccharide impurity in biotechnological applications, independent of the recombinant protein produced.


Subject(s)
Fermentation , Recombinant Proteins , Saccharomycetales , Recombinant Proteins/biosynthesis , Recombinant Proteins/metabolism , Recombinant Proteins/genetics , Saccharomycetales/metabolism , Saccharomycetales/genetics , Biomass , Batch Cell Culture Techniques , Polysaccharides/metabolism , Polysaccharides/biosynthesis
4.
Environ Sci Pollut Res Int ; 30(53): 114582-114590, 2023 Nov.
Article in English | MEDLINE | ID: mdl-37861840

ABSTRACT

The use of photocatalysts in continuous stirred tank reactor (CSTR) systems allows for efficient and continuous water treatment, thus meeting the demand for scalable technology and comparative data in large-scale implementations. Hence, this study aims to explore the feasibility of a floating photocatalyst within a CSTR system for continuous water treatment. An expanded polystyrene (EPS)-TiO2 composite was synthesized following established methodologies, and their efficacy in removing the water pollutant methylene blue (MB) was compared for both batch and CSTR systems. A nonlinear first-order model was identified as the most suitable approach to accurately simulate MB degradation under experimental conditions, and the calculated pseudo-first-order degradation rate constant (k') for the CSTR system (0.0126-0.0172/min) was found to be superior to that observed for the batch system (0.0113/min). In addition, an increase in the flow rate reduced the retention time, leading to lower MB removal efficiency for the CSTR system. In addition, the EPS-TiO2/UV system with a CSTR configuration was found to efficiently use light and energy based on the calculated quantum yield (Φ = 2.86 × 10-4) and electrical energy per order (EEO = 857.46 kWh/m3/order). The findings of this study contribute to the development of sustainable and efficient water treatment strategies, offering valuable insight into the implementation of practical water treatment processes.


Subject(s)
Bioreactors , Water Purification , Titanium , Electricity
5.
Environ Res ; 236(Pt 2): 116784, 2023 11 01.
Article in English | MEDLINE | ID: mdl-37517498

ABSTRACT

Water scarcity is increasing worldwide due to rising population which is creating opportunities to unlock alternative green desalination techniques for seawater, such as biodesalination. Therefore, this study presents the utilization of the Phormidium keutzingianum strain in an attached growth-packed bed reactor to treat seawater in real-time in a continuous-flow stirred tank reactor for biodesalination. Two reactors were designed and developed, in which zeolites were used as the support media for the attached growth. The experiment was conducted in an open outdoor environment with a continuous air flow rate of 3 mL/min and two hydraulic retention times (HRT) of 7 and 15 d. Parameters such as the pH, chloride ion concentration, total organic carbon (TOC), and optical density were monitored regularly. The pH change was not significant in either reactor and remained within the range of 7.25-8.0. Chloride ion removal was the most crucial component of biodesalination efficiency, with d 7 removal efficiencies of approximately 40% and 32% for reactors 1 and 2, respectively. Reactor 1 exhibited a TOC reduction of 36% within the first 10 d at a HRT of 7, and when the HRT was set to 15 d, a TOC removal efficiency of 89% was achieved on d 53. For reactor 2, a TOC removal efficiency of approximately 81% was achieved on d 11 at HRT 7, and it reduced to less than 50% at an HRT of 15. The chloride ion and TOC removal phenomena were similar in both reactors. The optical density (OD) showed low measurement recordings, ranging from 0.005 to 0.01, indicating low cell detachment in the seawater effluent. Therefore, using the attached growth method for the biodesalination of seawater is feasible. Furthermore, biomass harvesting in attached growth systems is easier than that in suspension growth systems.


Subject(s)
Bioreactors , Phormidium , Chlorides , Waste Disposal, Fluid/methods
6.
Mar Drugs ; 21(7)2023 Jul 19.
Article in English | MEDLINE | ID: mdl-37504942

ABSTRACT

Microalgae attract interest worldwide due to their potential for several applications. Scenedesmus is one of the first in vitro cultured algae due to their rapid growth and handling easiness. Within this genus, cells exhibit a highly resistant wall and propagate both auto- and heterotrophically. The main goal of the present work is to find scalable ways to produce a highly concentrated biomass of Scenedesmus rubescens in heterotrophic conditions. Scenedesmus rubescens growth was improved at the lab-scale by 3.2-fold (from 4.1 to 13 g/L of dry weight) through medium optimization by response surface methodology. Afterwards, scale-up was evaluated in 7 L stirred-tank reactor under fed-batch operation. Then, the optimized medium resulted in an overall productivity of 8.63 g/L/day and a maximum biomass concentration of 69.5 g/L. S. rubescens protein content achieved approximately 31% of dry weight, similar to the protein content of Chlorella vulgaris in heterotrophy.


Subject(s)
Chlorella vulgaris , Microalgae , Scenedesmus , Heterotrophic Processes , Scenedesmus/metabolism , Biomass , Microalgae/metabolism
7.
Biotechnol Bioeng ; 120(9): 2742-2755, 2023 09.
Article in English | MEDLINE | ID: mdl-37318000

ABSTRACT

The therapeutic effects of human mesenchymal stromal cells (MSC) have been attributed mostly to their paracrine activity, exerted through small-secreted extracellular vesicles (EVs) rather than their engraftment into injured tissues. Currently, the production of MSC-derived EVs (MSC-EVs) is performed in laborious static culture systems with limited manufacturing capacity using serum-containing media. In this work, a serum-/xenogeneic-free microcarrier-based culture system was successfully established for bone marrow-derived MSC cultivation and MSC-EV production using a 2  l-scale controlled stirred tank reactor (STR) operated under fed-batch (FB) or fed-batch combined with continuous perfusion (FB/CP). Overall, maximal cell numbers of (3.0 ± 0.12) × 108 and (5.3 ± 0.32) × 108 were attained at Days 8 and 12 for FB and FB/CP cultures, respectively, and MSC(M) expanded under both conditions retained their immunophenotype. MSC-EVs were identified in the conditioned medium collected from all STR cultures by transmission electron microscopy, and EV protein markers were successfully identified by Western blot analysis. Overall, no significant differences were observed between EVs isolated from MSC expanded in STR operated under the two feeding approaches. EV mean sizes of 163 ± 5.27 nm and 162 ± 4.44 nm (p > 0.05) and concentrations of (2.4 ± 0.35) × 1011 EVs/mL and (3.0 ± 0.48) × 1011 EVs/mL (p > 0.05) were estimated by nanoparticle tracking analysis for FB and FB/CP cultures, respectively. The STR-based platform optimized herein represents a major contribution toward the development of human MSC- and MSC-EV-based products as promising therapeutic agents for Regenerative Medicine settings.


Subject(s)
Extracellular Vesicles , Mesenchymal Stem Cells , Humans , Batch Cell Culture Techniques , Extracellular Vesicles/metabolism , Regenerative Medicine , Cell Proliferation
8.
Sci Total Environ ; 895: 165051, 2023 Oct 15.
Article in English | MEDLINE | ID: mdl-37391158

ABSTRACT

The discovery of complete ammonium oxidation (comammox) has redefined the perception of the nitrification process which plays a vital part in biological nitrogen removal (BNR) from wastewater. Despite the reported detection or cultivation of comammox bacteria in biofilm or granular sludge reactors, limited attempts have been made to enrich or assess comammox bacteria in floccular sludge reactors with suspended growth of microbes, which are most extensively applied at wastewater treatment plants. Therefore, through making use of a comammox-inclusive bioprocess model reliably evaluated using batch experimental data with joint contributions of different nitrifying guilds, this work probed into the proliferation and functioning of comammox bacteria in two commonly-used floccular sludge reactor configurations, i.e., continuous stirred tank reactor (CSTR) and sequencing batch reactor (SBR), under mainstream conditions. The results indicated that compared with the studied SBR, the CSTR was observed to favor the enrichment of comammox bacteria through maintaining a sufficient sludge retention time (40-100 d) while avoiding an extremely low DO level (e.g., 0.05 g-O2/m3), irrespective of the varied influent NH4+-N of 10-100 g-N/m3. Meanwhile, the inoculum sludge was found to greatly influence the start-up process of the studied CSTR. By inoculating the CSTR with a sufficient amount of sludge, finally enriched floccular sludge with a high abundance of comammox bacteria (up to 70.5 %) could be rapidly obtained. These results not only benefitted further investigation and application of comammox-inclusive sustainable BNR technologies but also explained, to some extent, the discrepancy in the reported presence and abundance of comammox bacteria at wastewater treatment plants adopting floccular sludge-based BNR technologies.


Subject(s)
Bioreactors , Sewage , Sewage/microbiology , Bioreactors/microbiology , Wastewater , Nitrification , Bacteria , Nitrogen , Oxidation-Reduction , Ammonia
9.
Water Res X ; 18: 100165, 2023 Jan 01.
Article in English | MEDLINE | ID: mdl-37250287

ABSTRACT

A key step for the production of polyhydroxyalkanoates (PHAs) from organic waste streams is the selection of a biomass with a high PHA-storage capacity (selection-step), which is usually performed in sequencing batch reactors (SBR). A major advancement would be to perform such selection in continuous reactors to facilitate the full-scale implementation of PHA production from municipal wastewater (MWW)-derived feedstock. The present study therefore investigates to what extent a simple continuous-flow stirred-tank reactor (CSTR) represents a relevant alternative to anSBR. To this end, we operated two selection reactors (CSTR vs. SBR) on filtered primary sludge fermentate while performing a detailed analysis of the microbial communities, and monitoring PHA-storage over long-term (∼150 days) and during accumulation batches. Our study demonstrates that a simple CSTR is as effective as an SBR in selecting biomass with high PHA-storage capacity (up to 0.65 gPHA gVSS-1) while being 50% more efficient in terms of substrate to biomass conversion yields. We also show that such selection can occur on VFA-rich feedstock containing nitrogen (N) and phosphorus (P) in excess, whereas previously, selection of PHA-storing organisms in a single CSTR has only been studied under P limitation. We further found that microbial competition was mostly affected by nutrient availability (N and P) rather than by the reactor operation mode (CSTR vs. SBR). Similar microbial communities therefore developed in both selection reactors, while microbial communities were very different depending on N availability. Rhodobacteraceae gen. were most abundant when growth conditions were stable and N-limited, whereas dynamic N- (and P-) excess conditions favoured the selection of the known PHA-storer Comamonas, and led to the highest observed PHA-storage capacity. Overall, we demonstrate that biomass with high storage capacity can be selected in a simple CSTR on a wider range of feedstock than just P-limited ones.

10.
Front Microbiol ; 14: 1128233, 2023.
Article in English | MEDLINE | ID: mdl-36970662

ABSTRACT

Introduction: Pharmaceutical wastewater frequently contains high levels of toxic pollutants. If they are discharged untreated, they pose a threat to the environment. The traditional activated sludge process and the advanced oxidation process do not sufficiently remove toxic and conventional pollutants from pharmaceutical wastewater treatment plants (PWWTPs). Methods: We designed a pilot-scale reaction system to reduce toxic organic pollutants and conventional pollutants from pharmaceutical wastewater during the biochemical reaction stage. This system included a continuous stirred tank reactor (CSTR), microbial electrolysis cells (MECs), an expanded sludge bed reactor (EGSB), and a moving bed biofilm reactor (MBBR). We used this system to further investigate the benzothiazole degradation pathway. Results and discussion: The system effectively degraded the toxic pollutants (benzothiazole, pyridine, indole, and quinoline) and the conventional chemicals (COD, NH4 +-N, TN). During the stable operation of the pilot-scale plant, the total removal rates of benzothiazole, indole, pyridine, and quinoline were 97.66, 94.13, 79.69, and 81.34%, respectively. The CSTR and MECs contributed the most to the removal of toxic pollutants, while the EGSB and MBBR contributed less to the removal of the four toxic pollutants. Benzothiazoles can be degraded via two pathways: the benzene ring-opening reaction and the heterocyclic ring-opening reaction. The heterocyclic ring-opening reaction was more important in degrading the benzothiazoles in this study. Conclusion: This study provides feasible design alternatives for PWWTPs to remove both toxic and conventional pollutants at the same time.

11.
Molecules ; 28(3)2023 Jan 19.
Article in English | MEDLINE | ID: mdl-36770669

ABSTRACT

The use of stereoselective phase-transfer catalysis as a reliable method for the enantioselective synthesis of optically active α-amino acid derivatives using achiral Schiff base esters has been well-developed in batch in the last 40 years. Recently, continuous flow technology has become of great interest in the academy and industry, since it offers safer process operating conditions and higher efficiency compared to a traditional batch processing. Herein, we wish to report the first example of enantioselective phase transfer benzylation of alanine Schiff base ester, under continuous flow conditions. Two different methodologies were investigated: a liquid-solid phase transfer catalytic benzylation using a packed-bed reactor and a liquid-liquid phase transfer catalytic benzylation in continuous stirred-tank reactors. Liquid-liquid phase transfer process in flow showed slightly better productivity than the batch process, while solid-liquid phase transfer benzylation proved much more advantageous in terms of productivity and space-time yield. Furthermore, continuous flow system allowed the isolation of benzylated product without any work up, with a significant simplification of the process. In both cases, phase transfer asymmetric benzylation promoted by Maruoka catalyst demonstrated high enantioselectivity of target quaternary amino ester in flow, up to 93% ee.

12.
J Environ Manage ; 335: 117573, 2023 Jun 01.
Article in English | MEDLINE | ID: mdl-36840995

ABSTRACT

Long chain fatty acids (LCFAs) are the key intermediate of anaerobic digestion of oily food waste, not completely soluble in a water-dominant anaerobic system due to their long hydrocarbon chains with hydrophobic property. Their effective concentration affects release of high methanogenic potential and system stability. A long-term continuous anaerobic digestion of oily food waste demonstrated excess methane production of even more than feedstock in an anaerobic continuous stirred tank reactor (CSTR). Assuming feedstock COD at 100%, approximately 120% of COD as methane could be achieved. Oil floating and crystallization with Ca salt resulting from the distribution heterogeneity of LCFAs in the CSTR were found responsible for the excess methane production. Moreover, slow conversion and accumulation of saturated LCFAs with relatively lower solubility played an important role as well. Compared with unsaturated oleic (C18:1) and linoleic acids (C18:2), around twice slower methane production rate and longer lag time could be observed for those saturated LCFAs. Mixing intensity was proved to be a critical controlling factor for methanogenesis and stability possibly by affecting interaction between oil/LCFAs and anaerobes to change effective lipid loading.


Subject(s)
Food , Methane , Refuse Disposal , Anaerobiosis , Fatty Acids , Oils , Refuse Disposal/methods
13.
Bioresour Technol ; 371: 128603, 2023 Mar.
Article in English | MEDLINE | ID: mdl-36634876

ABSTRACT

Methanol was produced in a two-stage integrated process using Methylosinus trichosporium NCIMB 11131. The first stage involved sequestration of methane to produce methanotrophic biomass, which was utilized as biocatalyst in the second stage to convert CO2 into methanol. A combinatorial process engineering approach of design of micro-sparger, engagement of draft tube, addition of mass transfer vector and elevation of reactor operating pressure was employed to enhance production of biomass and methanol. Maximum biomass titer of 7.68 g/L and productivity of 1.46 g/L d-1 were achieved in an airlift reactor equipped with a micro-sparger of 5 µm pore size, in the presence of draft tube and 10 % v/v silicone oil, as mass transfer vector. Maximum methane fixation rate was estimated to be 0.80 g/L d-1. Maximum methanol titer of 1.98 g/L was achieved under an elevated operating pressure of 4 bar in a high-pressure stirred tank reactor.


Subject(s)
Methane , Methylosinus trichosporium , Methanol , Carbon Dioxide , Solubility
14.
Waste Manag ; 156: 272-281, 2023 Feb 01.
Article in English | MEDLINE | ID: mdl-36521212

ABSTRACT

Only few studies on the behaviour of bioplastics in anaerobic co-digestion could be found in literature and most of them are conducted in batch mode. Despite the fact that continuous experiments confirm or add new insight to the findings acquired from batch ones, there is still lack of such studies. This work aims to cover this gap, carrying out a semi-continuous anaerobic co-digestion of food waste and cellulose acetate (which its behaviour under anaerobic environment is also quite unexplored). After a first evaluation of the potential methane production from each substrate at batch scale, the semi-continuous co-digestion of food waste and cellulose acetate was carried out in three configurations. During the semi-continuous process, a methane yield of 331 NmlCH4/gVS was generated from the co-digestion of food waste and cellulose acetate while bioplastics specimens achieved a weight loss of about 45 %. The results were both lower than the one obtained from batch co-digestion, although methane production rates were comparable regardless of being fed with or without bioplastics. An increase was registered after 65 days of semi-continuous process, due to the accumulation of CA specimens. This confirms the different degradation trends between bioplastics and food waste.


Subject(s)
Food , Refuse Disposal , Anaerobiosis , Bioreactors , Refuse Disposal/methods , Methane/metabolism , Biopolymers/metabolism , Cellulose/metabolism , Digestion , Biofuels
15.
Water Res ; 229: 119396, 2023 Feb 01.
Article in English | MEDLINE | ID: mdl-36463679

ABSTRACT

Dehalococcoides mccartyi strain CBDB1 is a strictly anaerobic organohalide-respiring bacterium with strong application potential to remediate aquifers and soils contaminated with halogenated aromatics. To date, cultivation of strain CBDB1 has mostly been done in bottles or fed-batch reactors. Challenges with such systems include low biomass yield and difficulties in controlling the growth conditions. Here, we report the cultivation of planktonic D. mccartyi strain CBDB1 in a continuous stirring tank reactor (CSTR) that led to high cell densities (∼8 × 108 cells mL-1) and dominance of strain CBDB1. The reactor culture received acetate, hydrogen, and the brominated amino acid D- or L-3,5-dibromotyrosine as substrates. Both D- and L-3,5-dibromotyrosine were utilized as respiratory electron acceptors and are promising for biomass production due to their decent solubility in water and the formation of a non-toxic debromination product, tyrosine. By monitoring headspace pressure decrease which is indicative of hydrogen consumption, the organohalide respiration rate was followed in real time. Proteomics analyses revealed that the reductive dehalogenase CbdbA238 was highly expressed with both D- and L-3,5-dibromotyrosine, while other reductive dehalogenases including those that were previously suggested to be constitutively expressed, were repressed. Denaturing gradient gel electrophoresis (DGGE) of amplified 16S rRNA genes indicated that the majority of cells in the community belonged to the Dehalococcoides although the CSTR was operated under non-sterile conditions. Hence, tightly controlled CSTR cultivation of Dehalococcoides opens novel options to improve biomass production for bioaugmentation and for advanced biochemical studies.


Subject(s)
Chloroflexi , Tyrosine , RNA, Ribosomal, 16S , Hydrogen , Chloroflexi/genetics , Biodegradation, Environmental
16.
Sci Total Environ ; 859(Pt 1): 160259, 2023 Feb 10.
Article in English | MEDLINE | ID: mdl-36402332

ABSTRACT

Horizontal flow wetlands have been designed using the so-called P-k-C* approach, which has been largely embraced by the treatment wetlands literature. P is meant to represent the equivalent number of apparent tanks in series (hydraulic factor), but also incorporates the loss of biodegradability as the wastewater undergoes treatment (kinetic factor). For design purposes, literature proposes fixed values of P. The proposal of this paper is to decouple hydraulics from kinetics and use the traditional concept of N or NTIS (number of tanks in series) as a function of geometric relationships of the wetland to be designed, leaving kinetic elements to be dealt with solely by the first-order removal rate coefficient (k). From the literature, a database with 41 wetlands with data from tracer studies was used, and a novel regression-based equation was derived relating N with the ratio length/depth of horizontal wetlands. This equation can be used at the design stage for estimating N and, hence, the output concentration of the pollutant using the traditional structure of the TIS model, with a possible inclusion of background concentration (C*). The paper presents all relevant equations, including those from the plug-flow with dispersion model (PFD), and it is shown how to convert from one hydraulic model to the other, what is also believed to be a novel approach in the treatment wetland literature. Finally, the area-based removal rate coefficients (kA) proposed by Kadlec and Wallace (2009) for designs of horizontal wetlands treating domestic wastewater based on the P-k-C* approach are converted into kA values for the TIS model in the paper.


Subject(s)
Waste Disposal, Fluid , Wetlands , Wastewater , Kinetics
17.
Adv Biochem Eng Biotechnol ; 184: 107-123, 2023.
Article in English | MEDLINE | ID: mdl-36355080

ABSTRACT

Traditionalists are reluctant to leave the technology they and their forefathers knew. To them the new technology based on the stirred tank bioreactor is too removed from the soil the mushroom comes from. On the other hand, there are examples of applications of a bioreactor which support the change from the old to the new technology. In this chapter Bjarmin Rushton, the creator of the well-known medicinal mushroom company Wellness, gives his view of the much talked about difficulties with cultivation in stirred tanks. These problems, are they real or figment of our imagination? Those who read will find out.


Subject(s)
Agaricales , Bioreactors
18.
Environ Sci Pollut Res Int ; 30(7): 17437-17448, 2023 Feb.
Article in English | MEDLINE | ID: mdl-36194331

ABSTRACT

Agaricus bisporus production gets a lot of residues, which could be fermented by a continuous stirred tank reactor (CSTR). This research was conducted to study the characteristics of the multiphase flow field in the reactor and its influence on the efficiency of biogas production in the CSTR fermentation process of Agaricus bisporus residue by using CFD numerical simulation technique. The aim is to reveal the relationship between the reactor operating conditions, flow field characteristics, and biogas production efficiency at the micro-level. We compared the results of different turbulence models by evaluating the power quotients and flow quotients with the experimental results to derive the most suitable flow field model inside the reactor for the Agaricus bisporus residues. The results showed that, under the condition that the number of grids does not affect the simulation results, and considering the model accuracy and efficiency, the numerical method can be chosen as the multiple reference frame (MRF) method of the second-order upwind discrete scheme with the realizable k - ε model. In this way, we can make use of edible mushroom residue as a substrate for resource utilization and provide basic data and theoretical basis for the design and scale-up with anaerobic fermentation to biogas reactor.


Subject(s)
Agaricus , Bioreactors , Fermentation , Biofuels
19.
J Environ Manage ; 324: 116447, 2022 Dec 15.
Article in English | MEDLINE | ID: mdl-36352722

ABSTRACT

Water resources planning and management are dependable on an adequate integration of physical, chemical, biological, and socio-economic realities of multiple water users. The dynamic of water quantity and quality in rivers are affected by several conditions, such as land use, soil characteristics, and meteorological and hydrological processes. Among these, the presence of hydraulic structures, such as dams and reservoirs, are often responsible for hydrodynamic and geomorphological alterations, leading to impacts on water quality and ecological behavior. In this context, this study presents the combination of a solution of the one-dimensional flow and transport and fate of contaminants in rivers (SihQual model) with a continuously stirred tank reactor (CSTR) to represent the reservoir. The first model solves the hydrodynamic and water quality equations under unsteady state, while the second approach considers the reservoir as a complete mixed system with inputs that vary over time. The main goal is to provide an integrated analysis for planning and management in a watershed where water has multiple purposes of use. The case study is the Iguaçu watershed, where the main river is affected by several dams for hydroelectric power generation. The simulation covers 542 km of the Iguaçu River and the Foz do Areia reservoir (flooded area of 139.5 km2), using data from 12 monitoring stations. The region also has issues of water quality impairment and water scarcity events due to deforestation, and urban and agricultural activities, exemplifying challenges throughout the world. Results show that the integrated models can reproduce the expected variability in different systems, although calibration challenges arise in multiscale modeling. The data indicate that, overall, the lentic environment is able to deplete organic matter and phosphorus, in comparison to levels in the fluvial flow. Nonetheless, experiments show that the river-reservoir system may be highly sensible to external and internal changes, such as water availability throughout time and pollution from the main tributary, as well as outlet discharges and transformation processes in the water column, leading to a possibility of critical events. Therefore, the study highlights how planning and managing actions in the watershed can benefit from an integrated river-reservoir analysis.


Subject(s)
Rivers , Water Pollutants, Chemical , Rivers/chemistry , Water Quality , Models, Theoretical , Hydrology , Phosphorus/analysis , Environmental Monitoring/methods , Water Pollutants, Chemical/analysis
20.
Materials (Basel) ; 15(21)2022 Oct 22.
Article in English | MEDLINE | ID: mdl-36363011

ABSTRACT

The use of materials requires adjusting their features to current applications/needs. In crystallization, the production methods leading directly to the product with pre-determined characteristics are being sought. The research focuses on the abilities of "shaping" the solid product (CSD, shape, form, etc.) and is based on experimental work carried out in the ultrasound (US)-assisted Koflo static mixer (STM). As the model reaction calcium fluoride precipitation has been used as a "common denominator" that complements the previous authors' studies, providing comprehensive knowledge and a more general look at the mentioned problem. It has been shown that it is possible to obtain crystals with the desired characteristics; however, one should be aware of the used reactors' limitations. The conscious selection of operating conditions, as well as US parameters (if they are used), is also essential. It has been revealed that the introduction of US to the STM only affects the turbulence intensity, but it doesn't change the mixing profile. The kinetics of crystallization remain unchanged, but crystals are subjected to greater attrition. In the stirred tank reactors, one might significantly improve the homogeneity of the unit mixing distribution by the selection of the relative input power εrel and, thus, affect the kinetics of crystallization.

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