TABLE 1.

Comparison of studies on PEF assisted protein extraction from E. coli.

Modus operandi	PEF matrix	Field strength (kV/cm)	Pulse frequency (Hz)	Pulse duration (μ s)	Energy input (kJ/kg)	Target protein	Investigated process variables	Comments	References
Batch	Buffers containing NaCl, glycine, and PEG	7.5–10	50	≤1	100–280	Recombinant β-glucosidasea, α-amylaseb, and cellobiohydrolasea,b	Protein release	Up to 89% release of α-amylase in combination with NaCl and PEG	Ohshima et al., 2000
Batch	dH2O	5–20	1–1,000	100–1,000	5.5–533.8	Total proteina,b	Viability, protein release	∼75% of total protein extracted	Haberl-Meglič et al., 2015; Haberl-Meglič et al., 2016
Continuous (0.08 L/h)	dH2O, subsequent incubation in “post pulse buffers”	5.5–7.5	4	500–2,000	n.a.	Native PGKa and GAPDHa	Viability, protein release, HCP impurity (qualitative)	Up to ∼90% release of native enzyme after incubation with specific buffers	Coustets et al., 2015
Continuous (0.6–1.98 L/h), recirculation to culture	Culture broth	12	2–3	n.a.	n.a.	Recombinant α-amylaseb	Viability, protein release, HCP impurity (qualitative)	30% release of α-amylase using intermittent PEF treatment	Shiina et al., 2004, 2007
Continuous (1.5 L/h)	Culture broth	25.6–38.4	50–1,000	3	10.3–257.6	Recombinant Protein Ab	Viability, protein release, HCP impurity (quantitative), DNA load, endotoxin load	Up to 89% release of recombinant periplasmic protein	This study

^aLocated in the cytoplasm. ^bLocated in the periplasm.