A New Test System for the In-Line Monitoring of Autoclave Exhaust Treatment: A Study of Uncertainty

Citation: Grumbach C, P Czermak: A new test system for the in-line monitoring of autoclave exhaust treatment: A study of uncertainty, Filtration 15 (2015) 4, 213-222The development of test systems to monitor the filtration of exhaust gases from laboratory autoclaves is driven by emerging laboratory safety regulations . The water intrusion test is suitable for this purpose, and therefore the test was adapted to account for the risks inherent in the filter systems used for the treatment of exhaust gas. To validate the test principle, the uncertainty of calibration and measurement was investigated using two commercial test gauges (Palltronice Flowstar XC, Sartocheck 4). The calibration data revealed a good fit (Rl = 0.988) over a measurement range of 0.0-3.0 mg/mL, confirming the stability of the test system. The uncertainty of the new test system corresponds to other measurement gauges in a range of ± 0.01 (for low flow rates) to ± 0.05 (for high flow rates). These data highlight the potential of our device for the development of reliable test systems for small plants, with adjusted costs for design, integration and qualification

Degradation of Lignin Derivatives by Photocatalysts

Photocatalytic degradation experiments were done with lignin sulfonate in a circulating reactor. Catalysts (TiO2-P25-SiO2 + Pt, TiO2-P25-SiO2, TiOSO4_30.6 wt%, ZnO + TiO2-P25-SiO2), synthesized via the sol–gel method, were immobilized on porous glass support material. A comparative study was done regarding morphology of coatings, degradation rates, reaction rates, dissolved carbon (DC), formation of peaks, and fluorescence of products formed from the photocatalytic degradation of lignin sulfonate obtained from a local paper plant. Through simultaneous reaction–extraction pathways applying dialysis filtration and highly porous polystyrene divinylbenzene adsorbent resin (HR-P) for solid-phase extraction (SPE), an attempt was been made to isolate smaller molecules produced from photocatalytic degradation. Moreover, relatively high lignin sulfonate (0.5 g/L) concentrations are used in the reactions. UV–Vis spectroscopy revealed a faster reduction in the concentration values for the aliphatic moiety compared to the aromatic moiety. Peaks were observed by both fluorescence spectroscopy and high-performance liquid chromotography (HPLC), suggesting the production of new substances and fluorophores

Membrane Technology for the Recovery of Lignin: A Review

Citation: Humpert, D., Ebrahimi, M., & Czermak, P. (2016). Membrane Technology for the Recovery of Lignin: A Review. Membranes, 6(3), 13. doi:10.3390/membranes6030042Utilization of renewable resources is becoming increasingly important, and only sustainable processes that convert such resources into useful products can achieve environmentally beneficial economic growth. Wastewater from the pulp and paper industry is an unutilized resource offering the potential to recover valuable products such as lignin, pigments, and water [1]. The recovery of lignin is particularly important because it has many applications, and membrane technology has been investigated as the basis of innovative recovery solutions. The concentration of lignin can be increased from 62 to 285 g.L-1 using membranes and the recovered lignin is extremely pure. Membrane technology is also scalable and adaptable to different waste liquors from the pulp and paper industry

Alternative strategy enables automation of up- and downstream processes for recombinant production of an antimicrobial peptide in E. coli

Standard production processes for antimicrobial peptides (amps) comprise of batch cultivations in upstream and chromatographic purification in down-stream. Although chromatography in most variations is limited in scale-up and one of the most expensive steps in the production chain it still remains the industrial gold standard in downstream processing. To overcome this bottleneck in the production chain, alternative column-free purification strategies with aggregating tags are a promising approach. Such a process can be automated and scaled-up in consent with reasonable expenses. However, new processes involving alternative downstream strategies have to be developed starting from scratch. In regards to vector design it must be considered whether the product is intended to be expressed in a soluble or insoluble form, in which cell compartment it shall be synthesized or what kind of plasmid features are needed for the realization of an automated downstream process. In this study the soluble production of an amp with several structural disulfide bonds was conducted in an E. coli strain with an oxidizing cytoplasm. To generate the expression vector a unique combination of plasmid features was assembled by Golden Gate cloning to enable an automated downstream procedure with aggregating tags for column-free purification. The junction of a thioredoxin-tag (trxA) with elastin-like-polypeptides (ELPs) and self-splicing inteins allows the release of the protein from the cytoplasm into the extracellular space and the separation from host cell proteins (HCP) in the bioreactor vessel. The trxA-tag acts as a solubility enhancer to the product and facilitates the release into the extracellular space via simple osmotic shock procedure. Reversible, temperature dependent phase transition of the ELPs enables purification of the desired product from impurities such as HCP and, after cleavage by self-splicing inteins, to separate the amp from the tags itself. Please click Additional Files below to see the full abstract

Lignin Degradation Processes and the Purification of Valuable Products

Lignin is a heterogeneous, phenolic and polydisperse biopolymer which resists degradation due to its aromatic and highly branched structure. Lignin is the most abundant renewable source of aromatic molecules on earth. The valorization of lignin could therefore provide a sustainable alternative to petroleum refineries for the production of valuable aromatic compounds. Even so, paper mills and lignocellulose feedstock biorefineries treat lignin largely as a waste product. In paper mills, 98% of technical lignin is incinerated for internal energy recovery while only 2% is used commercially (e.g. for the production of aromatics such as vanillin). The reasons for the underutilization of lignin include its recalcitrance to degradation and the challenge of separating mixtures of numerous degradation products. The successful valorization of lignin in the future thus depends on a broad understanding of biological and technical degradation processes, and the implementation of efficient product purification strategies. This article describes enzymatic, photocatalytic and thermochemical lignin degradation processes and considers purification methods for valuable lignin-derived degradation products. We focus on the potential of membrane-based separation technology, including data from our own recent research

Mathematical modeling of diafiltration

The main objective of this study is to provide a general mathematical model in a compact form for batch diafiltration techniques. The presented mathematical framework gives a rich representation of diafiltration processes due to the employment of concentration-dependent solute rejections. It unifies the existing models for constant volume dilution mode, variable volume dilution mode, and concentration mode operations. The use of such a mathematical framework allows the optimization of the overall diafiltration process. The provided methodology is particularly applicable for decision makers to choose an appropriate diafiltration technique for the given separation design problem

Concepts for the Production of Viruses and Viral Vectors in Cell Cultures

The industrial-scale manufacturing of viruses or virus-like particles in cell culture is necessary for gene therapy and the treatment of cancer with oncolytic viruses. Complex multistep processes are required in both cases, but the low virus titers in batch cultures and the temperature sensitivity of the virus particles limit the production scale. To meet commercial and regulatory requirements, each process must be scalable and reproducible and must yield high virus titers. These requirements are met by establishing a cell culture process that matches the properties of the virus/host-cell system and by using serum-free cell culture medium. This chapter focuses on two case studies to consider the different aspects of process design, such as the reactor configuration and operational mode: the continuous production of retroviral pseudotype vectors in a retroviral packaging cell line and the production of oncolytic measles virus vectors for cancer therapy

Dynamic oncolytic measles virus production

Oncolytic viruses can be effective weapons against cancer with few treatment options. For example the tissue culture–adapted Edmonston strains of measles virus (MV) have altered its receptor specificity and became selectively oncolytic with attenuated pathogenicity. Russel et al. showed in 2014 full remission in an advanced stage multiple myeloma patient after systemic application of genetically modified MV. In this clinical trial, the patient was treated by intravenous infusion of 1011 TCID50 (50% tissue culture infectious dose) - of an engineered MV encoding human sodium iodide symporter. Appropriate medical treatment with oncolytic viruses calls for high concentrations and absolute product purity. The main challenge in the field of viral bioprocess design is the low product stability. Although oncolytic MV production is feasible in a stirred tank bioreactor, the poor knowledge about the virus release and inactivation process hampers oncolytic MV production in industrial scale. As published by Weiss et al. already a simple transfer of the MV production process from a static cultivation system (e.g. T-Flask) into a dynamic system (e.g. STR) can dramatically reduce MV yield. As static systems are only suitable for small-scale processes, the process transfer into scalable dynamic systems is a bottleneck for a broad application of MV as cancer drugs. Beside their limited scalability, T-flasks or cell factories only allows the MV production in a batch mode. Through this process mode, the MV particles can be harvest only once and at an assumed time of harvest (TOH). In consideration of the short MV half-life of one and two hours at 37°C and 32°C respectively, the TOH is a critical point in bioprocessing. But measles viruses are known to be sensitive against the production temperature. Therefore an infection cycle adapted virus harvest with related synchronal purification is required. Virus membrane filtration represents a beneficial trade-off. Membrane-based filtration like cross flow filtration can process potentially large volumes and yielding high host cell concentration in the bioreactor. On the other hand, membrane based filtration processes are very unspecific. To remain the advantages of membrane filtration and increase the selectivity of the purification, membrane chromatography is a true alternative. Application of adsorptive membranes based on the electric interaction between charged components of the liquid phase including viruses and ionic groups immobilized on the solid membrane matrix, ion exchange membrane chromatography (IEMC) is a potentially simple and efficient method for MV concentration and purification. In present work, a continuous bioprocess concept for oncolytic MV production and purification for the use in cancer therapy will be presented

Feasibility Of Ceramic Ultra- And Nanofiltration Membranes For Removal Of Endotoxins

The removal of endotoxins, a potential contaminant of dialysis water and dialysate, is a very difficult task. The endotoxin removal capacity of commercial ceramic membranes with a nominal molecular weight cut-off of < 1,000 and adsorber membranes was investigated. The dead-end filtration results showed that all investigated ceramic membranes produce water meeting the European standards when challenged with low endotoxin concentrations, but only one membrane type succeeded at high endotoxin concentrations. In addition, we present preliminary analysis of the factors determining bacterial fragment removal from water of different ceramic and polymeric adsorptive membranes

A fast and simple assay to quantify bacterial leukotoxin activity

Citation: Oppermann T, S Schwarz, N Busse, P Czermak: A fast and simple assay to quantify bacterial leukotoxin activity, Electronic Journal of Biotechnology, (2016). Vol. 24 http://dx.doi.org/10.1016/j.ejbt.2016.10.001Background: Mannheimia haemolytica is the primary bacterial pathogen in causing bovine respiratory disease with tremendous annual losses in the cattle industry. The leukotoxin from M. haemolytica is the predominant virulence factor. Several leukotoxin activity assays are available but not standardized regarding sample preparation and cell line. Furthermore, these assays suffer from a high standard error, a prolonged time consumption and often complex sample pretreatments, which is important from the bioprocess engineering point of view. Results: Within this study, an activity assay based on the continuous cell line BL3.1 combined with a commercial available adenosine triphosphate viability assay kit was established. The leukotoxin activity was found to be strongly dependent on the sample preparation. Furthermore, the interfering effect of lipopolysaccharides in the sample could be successfully suppressed by adding polymyxin B. We reached a maximum relative P95 value of 14%, which is more than seven times lower compared to current available assays as well as a time reduction up to 88%. Conclusion: Ultimately, the established leukotoxin activity assay is simple, fast and has a high reproducibility. Critical parameters regarding the sample preparation were characterized and optimized making complex sample purification superfluous