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Rabello JP, da Silva Cavalcante PE, Leme J, Aragão Tejo Dias V, Correia Barrence FA, de Oliveira Guardalini LG, Bernardino TC, Nunes R, Barros IH, Tonso A, Calil Jorge SA, Fernández Núñez EG. Chemometrics and analytical blank on the at-line monitoring of Zika-VLP production using near-infrared spectroscopy. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2025; 326:125217. [PMID: 39369592 DOI: 10.1016/j.saa.2024.125217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2024] [Revised: 09/16/2024] [Accepted: 09/23/2024] [Indexed: 10/08/2024]
Abstract
The Zika disease caused by the Zika virus was declared a Public Health Emergency by the World Health Union (WHO), with microcephaly as the most critical consequence. Aiming to reduce the spread of the virus, biopharmaceutical organizations invest in vaccine research and production, based on multiple platforms. A crescent vaccine production approach is based on virus-like particles (VLP), for not having genetic material in its composition, hypoallergenic and non-mutant character. For bioprocess, it is essential to have means of real-time monitoring, which can be assessed using process analysis techniques such as Near-infrared (NIR) spectroscopy, that can be combined with chemometric methods, like Partial-Least Squares (PLS) and Artificial Neural Networks (ANN) for prediction of biochemical variables. This work proposes a biochemical Zika VLP upstream production at-line monitoring model using NIR spectroscopy comparing sampling conditions (with or without cells), analytical blank (air, ultrapure water), and spectra pre-processing approaches. Seven experiments in a benchtop bioreactor using recombinant baculovirus/Sf9 insect cell platform in serum-free medium were performed to obtain biochemical and spectral data for chemometrics modeling (PLS and ANN), composed by a random data split (80 % calibration, 20 % validation) for cross-validation of the PLS models and 70 % training, 15 % testing, 15 % validation for ANN. The best models generated in the present work presented an average absolute error of 1.59 × 105 cell/mL for density of viable cells, 2.37 % for cell viability, 0.25 g/L for glucose, 0.007 g/L for lactate, 0.138 g/L for glutamine, 0.18 g/L for glutamate, 0,003 g/L for ammonium, and 0.014 g/L for potassium.
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Li X, Gu J, Wu H, Xie Y. Pilot-scale process development for recombinant adeno-associated virus (rAAV) production based on high-density Sf9 cell culture. Virol J 2024; 21:281. [PMID: 39511576 PMCID: PMC11542467 DOI: 10.1186/s12985-024-02550-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2024] [Accepted: 10/21/2024] [Indexed: 11/15/2024] Open
Abstract
BACKGROUND In recent years, gene therapy drugs have been widely marketed, and their effectiveness and potential have been confirmed. Thus, increasing their production on an industrial scale is critical. Recombinant adeno-associated viruses (rAAVs) are optimal vectors for gene therapy applications, and the baculovirus expression vector system (BEVS), which is based on Sf9 cell culture, is a common tool for rAAV production. METHODS In this work, an Sf9 cell fed-batch process was developed using shake flasks. In the laboratory-scale bioreactor, four processes were selected as the key factors when carrying out the orthogonal experiment. On the basis of the equal P/V principle and considering the problem posed by air bubbles, a pilot-scale level bioreactor process was established. RESULTS Here, we describe a method in which a BEVS was used to produce rAAV vectors, with the cell density increasing to 22.8 × 106 cells/mL and the rAAV titre increasing to 20 × 1011 VG/mL upon adding feed material. By resolving the problems associated with high-density cell culture and air bubbles, this process was successfully scaled to a 50 L pilot-scale level. CONCLUSIONS This successful experiment not only provides a technological basis for further scale-up but also guarantees product capacity. We hope that this development process can provide reference data for studying cell culture-based drug production.
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Hsu T, Talley MJ, Yang P, Geiselhoeringer A, Yang C, Gorla A, Rahman MJ, Silva L, Chen D, Yang B. Identification of infectious viruses for risk-based virus testing of CHO unprocessed bulk using next-generation sequencing. Biotechnol Prog 2024; 40:e3485. [PMID: 39051853 DOI: 10.1002/btpr.3485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 04/30/2024] [Accepted: 05/24/2024] [Indexed: 07/27/2024]
Abstract
It is important to increase manufacturing speed to make medicines more widely available. One bottleneck for CHO-based drug substance release is the in vitro viral (IVV) cell-based assay on unprocessed bulk. To increase process speed, we evaluate the suitability of replacing the IVV cell-based assay with next-generation sequencing (NGS). First, we outline how NGS is currently used in the pharmaceutical industry, and how it may apply to CHO virus testing. Second, we examine CHO virus contamination history. Since prior virus contaminants can replicate in the production bioreactor, we perform a literature search and classify 159 viruses as high, medium, low, or unknown risk based on their ability to infect CHO cells. Overall, the risk of virus contamination during the CHO manufacturing process is low. Only six viruses were reported to have contaminated CHO bioprocesses over the past several decades, and were primarily caused by fetal bovine serum or cell culture components. These virus contamination events can be mitigated through limitation and control of raw materials, combined with virus testing and virus clearance technologies. The list of CHO infectious viruses provides a starting framework for virus safety risk assessment and NGS development. Furthermore, ICH Q5A (R2) includes NGS as a molecular method for adventitious agent testing, paving a path forward for modernizing CHO virus testing.
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Xu X, Farnós O, Paes BCMF, Nesdoly S, Kamen AA. Multivariate data analysis on multisensor measurement for inline process monitoring of adenovirus production in HEK293 cells. Biotechnol Bioeng 2024; 121:2175-2192. [PMID: 38613199 DOI: 10.1002/bit.28712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 03/31/2024] [Accepted: 04/01/2024] [Indexed: 04/14/2024]
Abstract
In the era of Biopharma 4.0, process digitalization fundamentally requires accurate and timely monitoring of critical process parameters (CPPs) and quality attributes. Bioreactor systems are equipped with a variety of sensors to ensure process robustness and product quality. However, during the biphasic production of viral vectors or replication-competent viruses for gene and cell therapies and vaccination, current monitoring techniques relying on a single working sensor can be affected by the physiological state change of the cells due to infection/transduction/transfection step required to initiate production. To address this limitation, a multisensor (MS) monitoring system, which includes dual-wavelength fluorescence spectroscopy, dielectric signals, and a set of CPPs, such as oxygen uptake rate and pH control outputs, was employed to monitor the upstream process of adenovirus production in HEK293 cells in bioreactor. This system successfully identified characteristic responses to infection by comparing variations in these signals, and the correlation between signals and target critical variables was analyzed mechanistically and statistically. The predictive performance of several target CPPs using different multivariate data analysis (MVDA) methods on data from a single sensor/source or fused from multiple sensors were compared. An MS regression model can accurately predict viable cell density with a relative root mean squared error (rRMSE) as low as 8.3% regardless of the changes occurring over the infection phase. This is a significant improvement over the 12% rRMSE achieved with models based on a single source. The MS models also provide the best predictions for glucose, glutamine, lactate, and ammonium. These results demonstrate the potential of using MVDA on MS systems as a real-time monitoring approach for biphasic bioproduction processes. Yet, models based solely on the multiplicity and timing of infection outperformed both single-sensor and MS models, emphasizing the need for a deeper mechanistic understanding in virus production prediction.
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Wang H, Hu X, Zhang M, Yang L, Xu Y, Gu X, Jiang J, Hu W. Development of an HSV-1 production process involving serum-reduced culturing and bead-to-bead transfer. Appl Microbiol Biotechnol 2024; 108:383. [PMID: 38896301 PMCID: PMC11186949 DOI: 10.1007/s00253-024-13193-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 05/10/2024] [Accepted: 05/21/2024] [Indexed: 06/21/2024]
Abstract
Herpes simplex virus type 1 (HSV-1) plays an important role in the field of gene therapy and viral vaccines, especially as an oncolytic virus. However, the mass production of HSV-1 viral vectors remains a challenge in the industry. In this study, a microcarrier-mediated serum-reduced medium culture was used to improve the bioprocess of HSV-1 production and increase HSV-1 yields. The composition of the culture media, which included a basal medium, serum concentration, and glutamine additive, was optimized. The process was successfully conducted in a 1 L bioreactor, and virus production was threefold greater than that of conventional processes with a 10% serum medium. The bead-to-bead transfer process was also developed to further increase scalability. In spinner flasks, the detachment rate increased from 49.4 to 80.6% when combined agitation was performed during digestion; the overall recovery proportion increased from 37.9 to 71.1% after the operational steps were optimized. Specifically, microcarrier loss was reduced during aspiration and transfer, and microcarriers and detached cells were separated with filters. Comparable cell growth was achieved with the baseline process using 2D culture as the inoculum by exchanging the subculture medium. To increase virus production after bead-to-bead transfer, critical parameters, including shear stress during digestion, TrypLE and EDTA concentrations in the subculture, and the CCI, were identified from 47 parameters via correlation analysis and principal component analysis. The optimized bead-to-bead transfer process achieved an average of 90.4% overall recovery and comparable virus production compared to that of the baseline process. This study is the first to report the optimization of HSV-1 production in Vero cells cultured on microcarriers in serum-reduced medium after bead-to-bead transfer. KEY POINTS: • An HSV-1 production process was developed that involves culturing in serum-reduced medium, and this process achieved threefold greater virus production than that of traditional processes. • An indirect bead-to-bead transfer process was developed with over 90% recovery yield in bioreactors. • HSV-1 production after bead-to-bead transfer was optimized and was comparable to that achieved with 2D culture as inoculum.
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Kadoya SS, Zhu Y, Chen R, Rong C, Li Y, Sano D. A soft-sensor approach for predicting an indicator virus removal efficiency of a pilot-scale anaerobic membrane bioreactor (AnMBR). JOURNAL OF WATER AND HEALTH 2024; 22:967-977. [PMID: 38935449 DOI: 10.2166/wh.2024.251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2023] [Accepted: 05/10/2024] [Indexed: 06/29/2024]
Abstract
The anaerobic membrane bioreactor (AnMBR) is a promising technology for not only water reclamation but also virus removal; however, the virus removal efficiency of AnMBR has not been fully investigated. Additionally, the removal efficiency estimation requires datasets of virus concentration in influent and effluent, but its monitoring is not easy to perform for practical operation because the virus quantification process is generally time-consuming and requires specialized equipment and trained personnel. Therefore, in this study, we aimed to identify the key, monitorable variables in AnMBR and establish the data-driven models using the selected variables to predict virus removal efficiency. We monitored operational and environmental conditions of AnMBR in Sendai, Japan and measured virus concentration once a week for six months. Spearman's rank correlation analysis revealed that the pH values of influent and mixed liquor suspended solids (MLSS) were strongly correlated with the log reduction value of pepper mild mottle virus, indicating that electrostatic interactions played a dominant role in AnMBR virus removal. Among the candidate models, the random forest model using selected variables including influent and MLSS pH outperformed the others. This study has demonstrated the potential of AnMBR as a viable option for municipal wastewater reclamation with high microbial safety.
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Wilde J, Boyes R, Robinson AV, Daisley BA, Botschner AJ, Brettingham DJL, Macpherson CV, Mallory E, Allen-Vercoe E. Assessing phage-host population dynamics by reintroducing virulent viruses to synthetic microbiomes. Cell Host Microbe 2024; 32:768-778.e9. [PMID: 38653241 DOI: 10.1016/j.chom.2024.04.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 01/31/2024] [Accepted: 04/01/2024] [Indexed: 04/25/2024]
Abstract
Microbiomes feature complex interactions between diverse bacteria and bacteriophages. Synthetic microbiomes offer a powerful way to study these interactions; however, a major challenge is obtaining a representative bacteriophage population during the bacterial isolation process. We demonstrate that colony isolation reliably excludes virulent viruses from sample sources with low virion-to-bacteria ratios such as feces, creating "virulent virus-free" controls. When the virulent dsDNA virome is reintroduced to a 73-strain synthetic gut microbiome in a bioreactor model of the human colon, virulent viruses target susceptible strains without significantly altering community structure or metabolism. In addition, we detected signals of prophage induction that associate with virulent predation. Overall, our findings indicate that dilution-based isolation methods generate synthetic gut microbiomes that are heavily depleted, if not devoid, of virulent viruses and that such viruses, if reintroduced, have a targeted effect on community assembly, metabolism, and prophage replication.
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Tang QL, Gu LX, Xu Y, Liao XH, Zhou Y, Zhang TC. Establishing functional lentiviral vector production in a stirred bioreactor for CAR-T cell therapy. Bioengineered 2021; 12:2095-2105. [PMID: 34047682 PMCID: PMC8806440 DOI: 10.1080/21655979.2021.1931644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 05/12/2021] [Accepted: 05/13/2021] [Indexed: 11/01/2022] Open
Abstract
As gene delivery tools, lentiviral vectors (LV) have broad applications in chimeric antigen receptor therapy (CAR-T). Large-scale production of functional LV is limited by the adherent, serum-dependent nature of HEK293T cells used in the manufacturing. HEK293T adherent cells were adapted to suspension cells in a serum-free medium to establish large-scale processes for functional LV production in a stirred bioreactor without micro-carriers. The results showed that 293 T suspension was successfully cultivated in F media (293 CD05 medium and SMM293-TII with 1:1 volume ratio), and the cells retained the capacity for LV production. After cultivation in a 5.5 L bioreactor for 4 days, the cells produced 1.5 ± 0.3 × 107 TU/mL raw LV, and the lentiviral transduction efficiency was 48.6 ± 2.8% in T Cells. The yield of LV equaled to the previous shake flask. The critical process steps were completed to enable a large-scale LV production process. Besides, a cryopreservation solution was developed to reduce protein involvement, avoid cell grafting and reduce process cost. The process is cost-effective and easy to scale up production, which is expected to be highly competitive.
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Bharti S, Mukherji S, Mukherji S. Antiviral application of colloidal and immobilized silver nanoparticles. NANOTECHNOLOGY 2021; 32:205102. [PMID: 33561842 DOI: 10.1088/1361-6528/abe489] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
This study explored the application of colloidal and immobilized silver nanoparticles (AgNPs) for inactivation of bacteriophages. Coliphages that are commonly used as indicators for enteric viruses, were used in this study. Colloidal AgNPs were synthesized via a chemical reduction approach using sodium borohydride as reducing agent and trisodium citrate as stabilizing agent. AgNP-immobilized glass substrate was prepared by immobilizing AgNPs on amine-functionalized glass substrate by post-immobilization method. The AgNP-immobilized glass substrate was also tested so as to minimize the release of AgNPs in the treated water. The characterization of AgNPs and the AgNP-immobilized glass surface was done using field emission gun-transmission electron microscopy and scanning electron microscopy. Studies conducted with varying concentrations of colloidal AgNPs displayed good antiviral activity for MS2 and T4 bacteriophage. Colloidal AgNPs at a dose of 60 μg ml-1 could completely inactivate MS2 and T4 bacteriophage within 30 and 50 min with an initial concentration of 103 PFU ml-1. Contaminated water (100 ml) in an unstirred batch reactor with an initial bacteriophage concentration of 103 PFU ml-1 could be inactivated by the AgNP-immobilized glass substrate (1 cm × 1 cm, containing 3.7 μg cm-2 silver) suspended centrally in the batch reactor. Complete 3-Log bacteriophage inactivation was achieved within 70 and 80 min for MS2 and T4 bacteriophage, respectively, while the aqueous silver concentration was less than 25 μg l-1. This is significantly lower than the recommended standard for silver in drinking water (i.e. 100 μg l-1, US EPA). Thus, AgNP-immobilized glass may have good potential for generating virus-free drinking water.
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Gränicher G, Coronel J, Trampler F, Jordan I, Genzel Y, Reichl U. Performance of an acoustic settler versus a hollow fiber-based ATF technology for influenza virus production in perfusion. Appl Microbiol Biotechnol 2020; 104:4877-4888. [PMID: 32291490 PMCID: PMC7228903 DOI: 10.1007/s00253-020-10596-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 03/10/2020] [Accepted: 03/31/2020] [Indexed: 12/24/2022]
Abstract
Process intensification and integration is crucial regarding an ever increasing pressure on manufacturing costs and capacities in biologics manufacturing. For virus production in perfusion mode, membrane-based alternating tangential flow filtration (ATF) and acoustic settler are the commonly described cell retention technologies. While acoustic settlers allow for continuous influenza virus harvesting, the use of commercially available membranes for ATF systems typically results in the accumulation of virus particles in the bioreactor vessel. Accordingly, with one single harvest at the end of a cultivation, this increases the risk of lowering the product quality. To assess which cell retention device would be most suitable for influenza A virus production, we compared various key performance figures using AGE1.CR.pIX cells at concentrations between 25 and 50 × 106 cells/mL at similar infection conditions using either an ATF system or an acoustic settler. Production yields, process-related impurities, and aggregation of viruses and other large molecules were evaluated. Taking into account the total number of virions from both the bioreactor and the harvest vessel, a 1.5-3.0-fold higher volumetric virus yield was obtained for the acoustic settler. In addition, fewer large-sized aggregates (virus particles and other molecules) were observed in the harvest taken directly from the bioreactor. In contrast, similar levels of process-related impurities (host cell dsDNA, total protein) were obtained in the harvest for both retention systems. Overall, a clear advantage was observed for continuous virus harvesting after the acoustic settler operation mode was optimized. This development may also allow direct integration of subsequent downstream processing steps. KEY POINTS: • High suspension cell density, immortalized avian cell line, influenza vaccine.
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Petrovich ML, Ben Maamar S, Hartmann EM, Murphy BT, Poretsky RS, Wells GF. Viral composition and context in metagenomes from biofilm and suspended growth municipal wastewater treatment plants. Microb Biotechnol 2019; 12:1324-1336. [PMID: 31410982 PMCID: PMC6801142 DOI: 10.1111/1751-7915.13464] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Accepted: 07/05/2019] [Indexed: 11/30/2022] Open
Abstract
Wastewater treatment plants (WWTPs) contain high density and diversity of viruses which can significantly impact microbial communities in aquatic systems. While previous studies have investigated viruses in WWTP samples that have been specifically concentrated for viruses and filtered to exclude bacteria, little is known about viral communities associated with bacterial communities throughout wastewater treatment systems. Additionally, differences in viral composition between attached and suspended growth wastewater treatment bioprocesses are not well characterized. Here, shotgun metagenomics was used to analyse wastewater and biomass from transects through two full-scale WWTPs for viral composition and associations with bacterial hosts. One WWTP used a suspended growth activated sludge bioreactor and the other used a biofilm reactor (trickling filter). Myoviridae, Podoviridae and Siphoviridae were the dominant viral families throughout both WWTPs, which are all from the order Caudovirales. Beta diversity analysis of viral sequences showed that samples clustered significantly both by plant and by specific sampling location. For each WWTP, the overall bacterial community structure was significantly different than community structure of bacterial taxa associated with viral sequences. These findings highlight viral community composition in transects through different WWTPs and provide context for dsDNA viral sequences in bacterial communities from these systems.
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Shepherd TR, Du RR, Huang H, Wamhoff EC, Bathe M. Bioproduction of pure, kilobase-scale single-stranded DNA. Sci Rep 2019; 9:6121. [PMID: 30992517 PMCID: PMC6467869 DOI: 10.1038/s41598-019-42665-1] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 04/05/2019] [Indexed: 11/13/2022] Open
Abstract
Scalable production of kilobase single-stranded DNA (ssDNA) with sequence control has applications in therapeutics, gene synthesis and sequencing, scaffolded DNA origami, and archival DNA memory storage. Biological production of circular ssDNA (cssDNA) using M13 addresses these needs at low cost. However, one unmet goal is to minimize the essential protein coding regions of the exported DNA while maintaining its infectivity and production purity to produce sequences less than 3,000 nt in length, relevant to therapeutic and materials science applications. Toward this end, synthetic miniphage with inserts of custom sequence and size offers scalable, low-cost synthesis of cssDNA at milligram and higher scales. Here, we optimize growth conditions using an E. coli helper strain combined with a miniphage genome carrying only an f1 origin and a β-lactamase-encoding (bla) antibiotic resistance gene, enabling isolation of pure cssDNA with a minimum sequence genomic length of 1,676 nt, without requiring additional purification from contaminating DNA. Low-cost scalability of isogenic, custom-length cssDNA is demonstrated for a sequence of 2,520 nt using a bioreactor, purified with low endotoxin levels (<5 E.U./ml). We apply these exonuclease-resistant cssDNAs to the self-assembly of wireframe DNA origami objects and to encode digital information on the miniphage genome for biological amplification.
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Nikolay A, Léon A, Schwamborn K, Genzel Y, Reichl U. Process intensification of EB66® cell cultivations leads to high-yield yellow fever and Zika virus production. Appl Microbiol Biotechnol 2018; 102:8725-8737. [PMID: 30091043 PMCID: PMC6153634 DOI: 10.1007/s00253-018-9275-z] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 07/24/2018] [Accepted: 07/25/2018] [Indexed: 01/01/2023]
Abstract
A live-attenuated, human vaccine against mosquito-borne yellow fever virus has been available since the 1930s. The vaccine provides long-lasting immunity and consistent mass vaccination campaigns counter viral spread. However, traditional egg-based vaccine manufacturing requires about 12 months and vaccine supplies are chronically close to shortages. In particular, for urban outbreaks, vaccine demand can be covered rarely by global stockpiling. Thus, there is an urgent need for an improved vaccine production platform, ideally transferable to other flaviviruses including Zika virus. Here, we present a proof-of-concept study regarding cell culture-based yellow fever virus 17D (YFV) and wild-type Zika virus (ZIKV) production using duck embryo-derived EB66® cells. Based on comprehensive studies in shake flasks, 1-L bioreactor systems were operated with scalable hollow fiber-based tangential flow filtration (TFF) and alternating tangential flow filtration (ATF) perfusion systems for process intensification. EB66® cells grew in chemically defined medium to cell concentrations of 1.6 × 108 cells/mL. Infection studies with EB66®-adapted virus led to maximum YFV titers of 7.3 × 108 PFU/mL, which corresponds to about 10 million vaccine doses for the bioreactor harvest. For ZIKV, titers of 1.0 × 1010 PFU/mL were achieved. Processes were automated successfully using a capacitance probe to control perfusion rates based on on-line measured cell concentrations. The use of cryo-bags for direct inoculation of production bioreactors facilitates pre-culture preparation contributing to improved process robustness. In conclusion, this platform is a powerful option for next generation cell culture-based flavivirus vaccine manufacturing.
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Miura T, Schaeffer J, Le Saux JC, Le Mehaute P, Le Guyader FS. Virus Type-Specific Removal in a Full-Scale Membrane Bioreactor Treatment Process. FOOD AND ENVIRONMENTAL VIROLOGY 2018; 10:176-186. [PMID: 29214559 DOI: 10.1007/s12560-017-9330-4] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 12/01/2017] [Indexed: 05/09/2023]
Abstract
We investigated removal of noroviruses, sapoviruses, and rotaviruses in a full-scale membrane bioreactor (MBR) plant by monitoring virus concentrations in wastewater samples during two gastroenteritis seasons and evaluating the adsorption of viruses to mixed liquor suspended solids (MLSS). Sapoviruses and rotaviruses were detected in 25% of MBR effluent samples with log reduction values of 3- and 2-logs in geometric mean concentrations, respectively, while noroviruses were detected in only 6% of the samples. We found that norovirus and sapovirus concentrations in the solid phase of mixed liquor samples were significantly higher than in the liquid phase (P < 0.01, t test), while the concentration of rotaviruses was similar in both phases. The efficiency of adsorption of the rotavirus G1P[8] strain to MLSS was significantly less than norovirus GI.1 and GII.4 and sapovirus GI.2 strains (P < 0.01, t test). Differences in the adsorption of viruses to MLSS may cause virus type-specific removal during the MBR treatment process as shown by this study.
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Sassi HP, Ikner LA, Abd-Elmaksoud S, Gerba CP, Pepper IL. Comparative survival of viruses during thermophilic and mesophilic anaerobic digestion. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 615:15-19. [PMID: 28961437 DOI: 10.1016/j.scitotenv.2017.09.205] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 09/18/2017] [Accepted: 09/19/2017] [Indexed: 04/14/2023]
Abstract
Micro-scale technology was used to obtain survival data for three animal viruses and two bacteriophages during anaerobic digestion. The data for adenoviruses, MS2 and Φ6 provide the first published reports for survival of these viruses during mesophilic anaerobic digestion. Data were also obtained for thermophilic digestion, which showed greater inactivation of viruses at the higher temperature. Data on the survival of Φ6 are of particular interest since it is a lipid-based virus which has been suggested as a surrogate for the Ebola virus. In contrast, MS2 was found to be an inappropriate surrogate for Ebola.
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Abstract
Protein-based nanoreactors are generated by encapsulating an enzyme inside the capsid of the cowpea chlorotic mottle virus (CCMV). Here, three different noncovalent methods are described to efficiently incorporate enzymes inside the capsid of these viral protein cages. The methods are based on pH, leucine zippers, and electrostatic interactions respectively, as a driving force for encapsulation. The methods are exclusively described for the enzymes horseradish peroxidase, glucose oxidase, and Pseudozyma antarctica lipase B, but they are also applicable for other enzymes.
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Lu R, Zhang C, Piatkovsky M, Ulbricht M, Herzberg M, Nguyen TH. Improvement of virus removal using ultrafiltration membranes modified with grafted zwitterionic polymer hydrogels. WATER RESEARCH 2017; 116:86-94. [PMID: 28324709 DOI: 10.1016/j.watres.2017.03.023] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2016] [Revised: 03/08/2017] [Accepted: 03/08/2017] [Indexed: 05/24/2023]
Abstract
Potable water reuse has been adopted by cities suffering water scarcity in recent years. The microbial safety in water reuse, especially with respect to pathogenic viruses, is still a concern for water consumers. Membrane filtration can achieve sufficient removal of pathogenic viruses without disinfection byproducts, but the required energy is intensive. In this study, we graft-polymerized zwitterionic SPP ([3-(methacryloylamino) propyl] dimethyl (3-sulfopropyl) ammonium hydroxide) on a 150 kDa ultrafiltration polyethersulfone membrane to achieve a significantly higher virus removal. The redox-initiated graft-polymerization was performed in an aqueous solution during filtration of the monomer and initiators, allowing for functionalizing the membrane pores with hydrophilic polySPP. Bacteriophage MS2 and human adenovirus type 2 (HAdV-2) were used as surrogates for pathogenic human norovirus and human adenovirus. The grafting resulted in ∼18% loss of the membrane permeability but an increase of 4 log10 in HAdV-2 removal and 3 log10 in MS2 removal. The pristine and the grafted membranes were both conditioned with soluble microbial products (SMP) extracted from a full-scale membrane bioreactor (MBR) in order to test the virus removal after fouling the membranes. After fouling, the HAdV-2 removal by the grafted membrane was 1 log10 higher than that of the pristine membrane. For MS2, the grafted membrane after fouling with SMP achieved an additional 5 log10 removal compared to the unmodified membrane. The simple graft-polymerization functionalization of commercialized membrane achieving enhanced virus removal efficiency highlights the promise of membrane filtration for pathogen control in potable water reuse.
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O'Brien E, Munir M, Marsh T, Heran M, Lesage G, Tarabara VV, Xagoraraki I. Diversity of DNA viruses in effluents of membrane bioreactors in Traverse City, MI (USA) and La Grande Motte (France). WATER RESEARCH 2017; 111:338-345. [PMID: 28107747 DOI: 10.1016/j.watres.2017.01.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 01/03/2017] [Accepted: 01/06/2017] [Indexed: 05/03/2023]
Abstract
This study assesses diversity of DNA viruses in the effluents of two membrane bioreactor (MBR) wastewater treatment plants (WWTPs): an MBR in the United States and an MBR in France. Viral diversity of these effluents is compared to that of a conventional activated sludge WWTP in the U.S. Diversity analysis indicates Herpesvirales to be the most abundant order of potentially pathogenic human DNA viruses in wastewater treated effluent in all utilities. Other potentially pathogenic human viruses detected include Adenoviridae, Parvoviridae, and Polyomaviridae. Bacteriophage order Caudovirales comprises the majority of DNA virus sequences in the effluent of all utilities. The choice of treatment process (MBR versus activated sludge reactor) utilized had no impact on effluent DNA viral diversity. In contrast, the type of disinfection applied had an impact on the viral diversity present in the effluent.
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Virus resistant cell lines: A paradigm shift in risk mitigation. Biotechnol Bioeng 2017; 114:480. [PMID: 28112806 DOI: 10.1002/bit.26110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Kadwell SH, Overton LK. Protein Expression in Insect and Mammalian Cells Using Baculoviruses in Wave Bioreactors. Methods Mol Biol 2016; 1350:263-284. [PMID: 26820862 DOI: 10.1007/978-1-4939-3043-2_12] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Many types of disposable bioreactors for protein expression in insect and mammalian cells are now available. They differ in design, capacity, and sensor options, with many selections available for either rocking platform, orbitally shaken, pneumatically mixed, or stirred-tank bioreactors lined with an integral disposable bag (Shukla and Gottschalk, Trends Biotechnol 31(3):147-154, 2013). WAVE Bioreactors™ were among the first disposable systems to be developed (Singh, Cytotechnology 30:149-158, 1999). Since their commercialization in 1999, Wave Bioreactors have become routinely used in many laboratories due to their ease of operation, limited utility requirements, and protein expression levels comparability to traditional stirred-tank bioreactors. Wave Bioreactors are designed to use a presterilized Cellbag™, which is attached to a rocking platform and inflated with filtered air provided by the bioreactor unit. The Cellbag can be filled with medium and cells and maintained at a set temperature. The rocking motion, which is adjusted through angle and rock speed settings, provides mixing of oxygen (and CO2, which is used to control pH in mammalian cell cultures) from the headspace created in the inflated Cellbag with the cell culture medium and cells. This rocking motion can be adjusted to prevent cell shear damage. Dissolved oxygen and pH can be monitored during scale-up, and samples can be easily removed to monitor other parameters. Insect and mammalian cells grow very well in Wave Bioreactors (Shukla and Gottschalk, Trends Biotechnol 31(3):147-154, 2013). Combining Wave Bioreactor cell growth capabilities with recombinant baculoviruses engineered for insect or mammalian cell expression has proven to be a powerful tool for rapid production of a wide range of proteins.
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Abstract
The ability to make a large variety of virus-like particles (VLPs) has been successfully achieved in the baculovirus expression vector system (BEVS)/insect cell system. The production and scale-up of these particles, which are mostly sought as vaccine candidates, are currently being addressed. Furthermore, these VLPs are being investigated as delivery agents for use as therapeutics. The use of host insect cells allows mass production of VLPs in a proven scalable system.
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Wu HC, Hu YC, Bentley WE. Tubular Bioreactor for Probing Baculovirus Infection and Protein Production. Methods Mol Biol 2016; 1350:461-467. [PMID: 26820873 DOI: 10.1007/978-1-4939-3043-2_23] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Probing the baculovirus infection process is essential in optimizing recombinant protein production. Typically, researchers monitor the infection process in stirred reactors that contain cells that have been infected at different times after virus inoculation, particularly if cells pass the primary infection and become infected by progeny virus. This chapter describes several alternative bioreactor systems for baculovirus infection. We provide an example alternative system that holds promise to avoid asynchronous distributions in infection time. Namely, we describe a two-stage reactor system consisting of an upstream continuous stirred tank reactor and a downstream tubular reactor with segmented plug flow for probing baculovirus infection and production.
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Chaudhry RM, Holloway RW, Cath TY, Nelson KL. Impact of virus surface characteristics on removal mechanisms within membrane bioreactors. WATER RESEARCH 2015; 84:144-52. [PMID: 26231580 DOI: 10.1016/j.watres.2015.07.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Revised: 07/06/2015] [Accepted: 07/13/2015] [Indexed: 05/06/2023]
Abstract
In this study we investigated the removal of viruses with similar size and shape but with different external surface capsid proteins by a bench-scale membrane bioreactor (MBR). The goal was to determine which virus removal mechanisms (retention by clean backwashed membrane, retention by cake layer, attachment to biomass, and inactivation) were most impacted by differences in the virus surface properties. Seven bench-scale MBR experiments were performed using mixed liquor wastewater sludge that was seeded with three lab-cultured bacteriophages with icosahedral capsids of ∼30 nm diameter (MS2, phiX174, and fr). The operating conditions were designed to simulate those at a reference, full-scale MBR facility. The virus removal mechanism most affected by virus type was attachment to biomass (removals of 0.2 log for MS2, 1.2 log for phiX174, and 3 log for fr). These differences in removal could not be explained by electrostatic interactions, as the three viruses had similar net negative charge when suspended in MBR permeate. Removals by the clean backwashed membrane (less than 1 log) and cake layer (∼0.6 log) were similar for the three viruses. A comparison between the clean membrane removals seen at the bench-scale using a virgin membrane (∼1 log), and the full-scale using 10-year old membranes (∼2-3 logs) suggests that irreversible fouling, accumulated on the membrane over years of operation that cannot be removed by cleaning, also contributes towards virus removal. This study enhances the current mechanistic understanding of virus removal in MBRs and will contribute to more reliable treatment for water reuse applications.
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Miura T, Okabe S, Nakahara Y, Sano D. Removal properties of human enteric viruses in a pilot-scale membrane bioreactor (MBR) process. WATER RESEARCH 2015; 75:282-91. [PMID: 25770448 DOI: 10.1016/j.watres.2015.02.046] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Revised: 01/20/2015] [Accepted: 02/19/2015] [Indexed: 05/03/2023]
Abstract
In order to evaluate removal properties of human enteric viruses from wastewater by a membrane bioreactor (MBR), influent, anoxic and oxic mixed liquor, and membrane effluent samples were collected in a pilot-scale anoxic-oxic MBR process for 16 months, and concentrations of enteroviruses, norovirus GII, and sapoviruses were determined by real-time PCR using murine norovirus as a process control. Mixed liquor samples were separated into liquid and solid phases by centrifugation, and viruses in the bulk solution and those associated with mixed liquor suspended solids (MLSS) were quantified. Enteroviruses, norovirus GII, and sapoviruses were detected in the influent throughout the sampling period (geometrical mean, 4.0, 3.1, and 4.4 log copies/mL, respectively). Enterovirus concentrations in the solid phase of mixed liquor were generally lower than those in the liquid phase, and the mean log reduction value between influent and anoxic mixed liquor was 0.40 log units. In contrast, norovirus GII and sapovirus concentrations in the solid phase were equal to or higher than those in the liquid phase, and higher log reduction values (1.3 and 1.1 log units, respectively) were observed between influent and anoxic mixed liquor. This suggested that enteroviruses were less associated with MLSS than norovirus GII and sapoviruses, resulting in lower enterovirus removal in the activated sludge process. Enteroviruses and norovirus GII were detected in the MBR effluent but sapoviruses were not in any effluent samples. When MLSS concentration was reduced to 50-60% of a normal operation level, passages of enteroviruses and norovirus GII through a PVDF microfiltration membrane were observed. Since rejection of viruses by the membrane was not related to trans-membrane pressure which was monitored as a parameter of membrane fouling, the results indicated that adsorption to MLSS plays an important role in virus removal by an MBR, and removal properties vary by viruses reflecting different adsorptive behavior to MLSS. Our observations suggested that sapoviruses are more associated with MLSS and removed more efficiently than enteroviruses and norovirus GII.
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Chaudhry RM, Nelson KL, Drewes JE. Mechanisms of pathogenic virus removal in a full-scale membrane bioreactor. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015. [PMID: 25642587 DOI: 10.1016/j10.1021/es505332n] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Four pathogenic virus removal mechanisms were investigated in a full-scale membrane bioreactor (MBR; nominal pore size 0.04 μm): (i) attachment of virus to mixed liquor solids; (ii) virus retention by a just backwashed membrane; (iii) virus retention by the membrane cake layer; and (iv) inactivation. We quantified adenovirus, norovirus genogroup II (GII), and F+ coliphage in the influent wastewater, the solid and liquid fractions of the mixed liquor, return flow, and permeate using quantitative PCR (adenovirus and norovirus GII) and infectivity assays (F+ coliphage). Permeate samples were collected 4-5 days, 1 day, 3 h, and immediately after chlorine enhanced backwashes. The MBR achieved high log removals for adenovirus (3.9 to 5.5), norovirus GII (4.6 to 5.7), and F+ coliphage (5.4 to 7.1). The greatest contribution to total removal was provided by the backwashed membrane, followed by inactivation, the cake layer, and attachment to solids. Increases in turbidity and particle counts after backwashes indicated potential breakthrough of particles, but virus removal following backwashes was still high. This study demonstrates the ability of the MBR process to provide over 4 logs of removal for adenovirus and norovirus GII, even after a partial loss of the cake layer, and provides evidence for assigning virus disinfection credit to similar MBRs used to reclaim wastewater for reuse.
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