Table 3 Examples of PEF application in biorefineries
Biorefinery application | Examples | PEF parameters | Achieved effects |
|---|---|---|---|
Delivery of genes to improve feedstock phenotype and resistance | Plants: Mexican sweet maize | 750 V/cm, 15 × 103 µs pulse duration, single pulse | Transient expression of GUS and CAT, and stable expression of phosphinothricin acetyltransferase [73] |
Algae (strains development): Chlamydomonas | ~1900 V/cm, single pulse of exponential shape with 10 µF capacitor discharge | 2 × 105 transformants per µg of DNA [77] | |
Dehydration | Sugar beet cossettes | 3–5 kV/cm, 1.6 µs pulse duration, 40–80 pulses [88] 600 V/cm, 100 µs pulse duration, 100 pulses, 2.76 ± 0.16 Wt/kg [87] | PEF reduced the force required for a beet slicing from 16 to 8 N, reducing the total process energy requirement, and costs on changing the blades. In addition, combination with lime reduced the extraction process temperature from 72 to 60 °C with the same extraction efficiency [88] Lime improved the drying efficiency: 40 % dry matter content of the pulp was archived with less energy invested in evaporation than in untreated samples [87, 88] |
Green rye | 3.5 kV/cm, 1.5 µs pulse duration, 80 pulses | 8 % reduction in relative humidly after PEF + pressing with extrusion press. 100 min reduction time in drying under 105 °C in comparison with untreated controls [51] | |
Grass, maize, and lucerne drying | 7 kV/cm, 1.5 µs pulse duration, 40–80 pulses | >50 % energy saving in comparison with traditional methods [89] | |
High-value products extraction from biomass waste | Polyphenol extraction from involucral bracts of artichokes | 5 kV/cm, 10 µs pulse duration, 100 pulses, 5 kJ/kg, pulse repetition frequency 10 Hz | Almost totally destroyed membranes according to disintegration index (Z p = 0.9) extraction solvent: water. Extraction yield of polyphenols increased by 150 % in comparison with untreated samples. [96] |
Polyphenol extraction from grape by-products (pomace, peels, seeds, and vine shoots) | 20 kV/cm, 10 µs pulse duration, 2000 pulses, pulse repetition frequency 0.33 Hz | ||
Total polyphenols and flavonoids (naringin and hesperidin) extraction from orange peel | 7 kV/cm, pulse duration 3 µs, 20 pulses, pulse repetition frequency 1 Hz 5 kV/cm 3 µs, 20 pulses, pulse repetition frequency 1 Hz | Increased the total polyphenol extraction yield by 159 % [101] 3.1 mg/100 g yields of naringin and hesperidin [101] | |
Lignocellulose biomass pretreatment | Wood chip | 10 kV/cm, 100 µs pulse duration, 2000 pulses, pulse repetition frequency 3 Hz, | Permeability increase to neutral red dye [34] |
Switch grass | 8 kV/cm, 100 µs pulse duration, up to 5000 pulses | Permeability increase to neutral red dye [34] | |
Biofuel production | Yeast: in Saccharomyces cerevisiae, a major industrial fermentation organism | 2.7 kV/cm, 15 × 103 µs pulse duration, single pulse | Transformation efficiencies of 107 transformants/µg of plasmid DNA were achieved, providing exciting opportunities for high-throughput genetic engineering of strains for biofuel fermentation [84] |
Microalgae: A. protothecoides | 34 kV/cm, 1 µs pulse duration, ~0.75 MJ/kg | Cell rupture and release 15 % of algae dry weight to the medium [157] | |
C. vulgaris | 3 kV/cm, 2 × 103 µs pulse duration, 30 pulses, flow rate = 1 ml/s | Protein extraction yields: 3.5 µg protein/100 µl solution (107 cells/ml) [131] | |
N. salina | 6 kV/cm, 2 × 103 µs pulse duration, 30 pulses, flow rate = 150 µl/s | Protein extraction yields: 5 µg protein/100 µl solution (108 cells/ml) [131] | |
Biogas: waste activated sludge and pig manure | 10 kWh/m3 | Increased biomethane production by 80 % for pig manure and 100 % for WAS after 25–30 days [146] |