Elsevier

Available online 8 January 2020, 102288

Innovative Food Science & Emerging Technologies

Highlights

Pulsed electric field generator with gravitation press electrodes was developed for seaweed biomass electroporation.

Asymmetric voltage multiplying architecture allows to control the voltage of each pulse.

PEF parameters 4 kV, 1 kA, 1–100 μs duration and total power dissipation of 20 W

Macroalgae Ulva sp. was treated with 124 ± 12 V mm−1, pulse duration 50 μs, pulse number 50, frequency 3 Hz.

Electroporation of the biomass was confirmed with bioimpedance measurements.

Abstract

Optimization of protocols is required for each specific type of biomass processed by electroporation of the cell membrane with high voltage pulsed electric fields (PEF). Such optimization requires convenient and adaptable laboratory systems, which will enable determination of both electrical and mechanical parameters for successful electroporation and fractionation. In this work, we report on a laboratory PEF system consisting of a high voltage generator with a novel asymmetric voltage multiplying architecture and a treatment chamber with sliding electrodes. The system allows applying pulses of up to 4 kV and 1 kA with a pulse duration between 1 μs and 100 μs. The allowable energy dissipated per pulse on electroporated biomass is determined by the conditions for cooling the biomass in the electroporation cell. The device was tested on highly conductive green macroalgae from Ulva sp., a promising but challenging feedstock for the biorefinery. Successful electroporation was confirmed with bioimpedance measurements.

Industrial relevance

Seaweed biomass is an emerging feedstock for biorefineries with already 30 million tons per year of global industrial production. However, most of the biomass produced today is lost. Pulsed electric field (PEF) extraction could allow saving energy on biomass drying, deashing and it could allow extracting various organic compounds. However, the parameters needed to seaweed biomass treatment with PEF are not known and will differ from species to species. Furthermore, very high salt content challenges most of the available laboratory PEF devices, limiting the ability for parameters optimization in the lab. The developed laboratory scale PEF system coupled to bioimpedance measurement provides a necessary set of tools and methods for PEF parameters optimization required for process scale-up.

Abbreviations

CPE

constant phase element

R

sample impedance at infinite frequency

R0

sample impedance at zero frequency

τ

the characteristic time constant of the sample

α

a dimensionless parameter with a theoretical value between 0 and 1

Q0

the capacitance value of the seaweed in the chamber

ESC

energy storage capacitor

UESC

voltage on the storage capacitor

RCL

the resistance to charge current

CESC

capacity of the energy storage capacitor

Um

value of the maximum doubled voltage

CCL

capacitance of the charging capacitor

GPED

gravitational press-electrode device

Keywords

Pulsed electric field generator

Electroporation

Biomass processing

Macroalgae

Bioimpedance

Bioeconomy

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