Challenges and limitations for the decontamination of high solids protein solutions at neutral pH using pulsed electric fields

Schottroff, Felix; Johnson, Katja; Johnson, Nicholas; Bédard, Matthieu F.; Jaeger, Henry

doi:10.1016/j.jfoodeng.2019.109737

Cited by 14 publications

(8 citation statements)

References 15 publications

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“…Thus, the short pulse width applied in the present study might have prevented irreversible pore formation to an extent. Moreover, low inactivation may be explained by neutral pH during PEF treatment or high concentration of “solids,” which prevent inactivation of cells despite occurrence of electroporation ( Jaeger et al, 2009b ; Schottroff et al, 2020a ).…”

Section: Resultsmentioning

confidence: 99%

Selective Release of Recombinant Periplasmic Protein From E. coli Using Continuous Pulsed Electric Field Treatment

Schottroff

Kastenhofer

Spadiut

et al. 2021

Front. Bioeng. Biotechnol.

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To date, high-pressure homogenization is the standard method for cell disintegration before the extraction of cytosolic and periplasmic protein from E. coli. Its main drawback, however, is low selectivity and a resulting high load of host cell impurities. Pulsed electric field (PEF) treatment may be used for selective permeabilization of the outer membrane. PEF is a process which is able to generate pores within cell membranes, the so-called electroporation. It can be readily applied to the culture broth in continuous mode, no additional chemicals are needed, heat generation is relatively low, and it is already implemented at industrial scale in the food sector. Yet, studies about PEF-assisted extraction of recombinant protein from bacteria are scarce. In the present study, continuous electroporation was employed to selectively extract recombinant Protein A from the periplasm of E. coli. For this purpose, a specifically designed flow-through PEF treatment chamber was deployed, operated at 1.5 kg/h, using rectangular pulses of 3 μs at specific energy input levels between 10.3 and 241.9 kJ/kg. Energy input was controlled by variation of the electric field strength (28.4–44.8 kV/cm) and pulse repetition frequency (50–1,000 Hz). The effects of the process parameters on cell viability, product release, and host cell protein (HCP), DNA, as well as endotoxin (ET) loads were investigated. It was found that a maximum product release of 89% was achieved with increasing energy input levels. Cell death also gradually increased, with a maximum inactivation of -0.9 log at 241.9 kJ/kg. The conditions resulting in high release efficiencies while keeping impurities low were electric field strengths ≤ 30 kV/cm and frequencies ≥ 825 Hz. In comparison with high-pressure homogenization, PEF treatment resulted in 40% less HCP load, 96% less DNA load, and 43% less ET load. Therefore, PEF treatment can be an efficient alternative to the cell disintegration processes commonly used in downstream processing.

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Section: Resultsmentioning

confidence: 99%

Selective Release of Recombinant Periplasmic Protein From E. coli Using Continuous Pulsed Electric Field Treatment

Schottroff

Kastenhofer

Spadiut

et al. 2021

Front. Bioeng. Biotechnol.

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“…Especially at neutral pH, without the presence of additional anti-microbial hurdles (Leistner, 1995) and for challenging products with higher viscosities or contents of protective ingredients, this can have pronounced negative implications on the quality of the treated product, as a high level of energy input and an associated occurrence of pronounced hot spots may be necessary to achieve the desired microbial log reduction. Limitations regarding the processability of such products and negative implications on bioactive compounds have been shown earlier (Schottroff et al, 2020).…”

Section: Introductionmentioning

confidence: 91%

“…This leads to the conclusion that, in general, the vortex configuration produces a larger fraction of lethally injured cells, reducing the amount of sublethal injury. This is a beneficial attribute, as especially at neutral pH, inactivation of microorganisms by PEF may be difficult, due to the lack of additional hurdles and possible recovery of sublethally injured cells after the treatment (Schottroff et al, 2019(Schottroff et al, , 2020. Moreover, the increased inactivation, especially at neutral pH, can be interpreted as a further confirmation of the increased temperature homogeneity in the vortex chamber, therefore potentially promoting possible synergistic microbial inactivation effects of temperature and electric field (Jayaram et al, 1991), by reduction of local cold spots inside the chamber.…”

Section: Performance For Microbial Inactivationmentioning

confidence: 99%

Development of a Continuous Pulsed Electric Field (PEF) Vortex-Flow Chamber for Improved Treatment Homogeneity Based on Hydrodynamic Optimization

Schottroff

Knappert

Eppmann

et al. 2020

Front. Bioeng. Biotechnol.

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“…At a low pH, acid medium can penetrate into the damaged cells, modifying the intracellular pH and then leading to death (Schottroff et al . 2020). Adding an ultrasound step to PEF did not impart any additional effects on the inactivation of L .…”

Section: Pulsed Electric Field Treatment Of Milk and Subsequent Chees...mentioning

confidence: 99%

Potential applications of pulsed electric field in cheesemaking

Gentès

Caron

Champagne

2022

Int J of Dairy Tech

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Consumers show interest in preservation technologies that are not based on heating. This review examines the use of nonthermal technologies such as pulsed electric field (PEF) in cheesemaking. The effects of PEF on the destruction of pathogens in cheesemaking milk, as well as in brines, are examined. Additionally, PEF affects milk proteins and lipids, as well as starters, with potential consequences for the sensory properties of cheese. The challenges of scaling up the PEF in cheesemaking are addressed. In the aim of promoting durable agri-food systems, applications of PEF in processes of cheese whey valorisation are also discussed.

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Challenges and limitations for the decontamination of high solids protein solutions at neutral pH using pulsed electric fields

Cited by 14 publications

References 15 publications

Selective Release of Recombinant Periplasmic Protein From E. coli Using Continuous Pulsed Electric Field Treatment

Selective Release of Recombinant Periplasmic Protein From E. coli Using Continuous Pulsed Electric Field Treatment

Development of a Continuous Pulsed Electric Field (PEF) Vortex-Flow Chamber for Improved Treatment Homogeneity Based on Hydrodynamic Optimization

Potential applications of pulsed electric field in cheesemaking

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