Electrodialysis with porous membrane for bioproduct separation: Technology, features, and progress

Highlights

• An EDPM technique for separation and purification of bioactive products was proposed.

• The principle, operating mode and cell configuration of EDPM process were reviewed.

• The process optimization, membrane fouling and applications for EDPM were discussed.

• Pilot scale studies of EDPM provide more possibilities for full scale application.

Abstract

Electrodialysis with porous membrane (EDPM) is a recently developed membrane separation process, in which one or more porous filtration membranes stacked in an electrodialysis cell. It is a promising technology for separation, purification or concentration of bioactive components for it associates the excellent properties of electrodialysis (ED), porous filtration membrane, and electrophoresis. There are a number of studies having attempted to optimize the performance of EDPM processing, however, it still has some limitations involving low productivity with one pair of separation unit, membrane fouling and few applications on the fractionation of components with high molecular weight. This paper offers a comprehensive overview of recent studies devoted to EDPM, including principles, configurations, mathematical model regarding mass transfer, process performance optimization, membrane fouling and applications in as much detail as possible. In addition, a collection of other separation technologies based on electrophoresis at a preparative scale are presented to illustrate their limitations on the large-scale application. Some drawbacks of EDPM have been put forward. To achieve full scale applications of EDPM, there are still many issues to overcome. Finally, an outlook for prospective development of EDPM technology is given.

Introduction

In recent years, the needs for renewable resources have accelerated the development of biotechnology research in academia, industries, and laboratories funded by government (Saxena, Tripathi, Kumar, & Shahi, 2009). In particular, the demands for biological food, nutraceuticals, and pharmaceuticals with different beneficial functions have rapidly grown. These beneficial functions are attributed to the adding of bioactive substances, such as amino acids, peptides, and proteins obtained from animals or plants with different functions including antihypertensive (S. H. Lee et al., 2010, Puchalska et al., 2015, Ruiz-Gimenez et al., 2012), antioxidant (Marambe et al., 2008, Mendis et al., 2005, You and Wu, 2011), antibacterial (Pompilio et al., 2011, Zheng and Zhu, 2003), antitumor (Broggini et al., 2003, Chalamaiah et al., 2018), anti-inflammatory (C. C. Udenigwe, Lu, Han, Hou, & Aluko, 2009), and immunomodulatory (Chalamaiah et al., 2018, Yang et al., 2009). Therefore, it is important to choose efficient bioseparation methods to recover and purify these bioactive components or fragments from a complex mixture with high selectivity. Chromatographic and electrophoretic techniques have high separation resolution for bioproduct separation, however, their productivities are low. In addition, the cost of chromatography is high (Bargeman et al., 2002).

Currently, membrane-based separation technologies have been received considerable attention and have been widely used for various chemical and biological industries, such as wastewater and drinking water treatment, industrial production, and concentration and desalination of seawater, as well as separation and purification for biologically-active molecules or fragments. These methods are effective, economical, safe to the environment, easy to operate, and can be used in large industrial-scale applications. Various membrane processes have been introduced into industrial production lines, and membranes have become necessary tools in the field of biotechnology (Saxena et al., 2009). The most commonly used membrane processes for bioseparation is pressure-driven membrane filtration technology, including microfiltration, ultrafiltration, nanofiltration, and reverse osmosis (MF, UF, NF, and RO, respectively) (Y. Pouliot, Gauthier, Groleau, Mine, & Shahidi, 2006). They have extensive applications in biotechnological pursuits, particularly in the food and beverage industry operations (Darnon, Morin, Belleville, & Rios, 2003). Numerous bioactive proteins and peptides have been separated (Brans et al., 2004, Mejia and Lumen, 2006, Ryan et al., 2011), especially using UF and NF membranes (UFM and NFM, respectively) (Korhonen & Pihlanto, 2006). Nevertheless, low selectivity and membrane fouling resulting from particle accumulation on membrane surfaces are the main limitations for the pressure-driven membrane operations (Bazinet and Firdaous, 2013, Belfort, 2019). Moreover, sometimes, to separate the desired components from a mixture, a multi-stage separation with different apertures’ membranes is needed. However, this leads to high costs and low separation efficiency. Therefore, improving separation resolution is one of the most sought-after objectives in membrane technology, such that many studies have been devoted to this goal. For instance, a stimulus-responsive membrane has become a research hotspot in the international membrane science field, involving a new membrane type in which the structure or separation characteristics of the membrane can be altered by changing the membrane pore size according to environmental conditions, including pH, temperature, electric field, and ionic strength (Liu et al., 2016, Ye et al., 2017; C. Zhao, Nie, Tang, & Sun, 2011). Thus, the membrane aperture can be precisely controlled and process selectivity greatly enhanced. Anything else, an electromembrane filtration process, that electric fields have been imposed during the membrane filtration operation, has also been studied to increase process selectivity and production as well as to reduce membrane fouling (Holder et al., 2013, Brisson et al., 2007, Lapointe et al., 2006). However, what is particularly noteworthy is a hybrid process in recent years, electrodialysis with porous filtration membranes (EDPM), which has been extensively studied and developed for the separation and purification of charged bioactive peptides, fragments or molecules from different mixtures with its high selectivity (Doyen et al., 2014, Durand et al., 2019, He et al., 2016).

This new technology extends the application of electrodialysis (ED) especially in the bioseparation field, since compounds of higher molecular weights (MWs) cannot be separated by ED due to the narrow pores of ion exchange membranes (IEMs) (Y. Wang, Jiang, Bazinet, & Xu, 2019). The EDPM process can obtain higher selectivity than filtration membranes for its effective separation of components with similar MW (Sylvain Galier & Roux-de Balmann, 2011), while reducing membrane fouling. It can easily be used in large scale, which amplifies the electrophoretic operation, and its cost is lower than that of chromatography (Bargeman et al., 2002). In addition, the gentle operating conditions of the EDPM process can retain the activity of biological fractions or molecules. This further improves its applicability in biological separation. Therefore, many researchers have studied this technology in recent years and a comprehensive summary of the current situation for EDPM is needed.

Here, a number of studies regarding the EDPM process in recent years are shown in Fig. 1. A bibliometric method is used to discuss the data shown in this figure. Firstly, respectively taking electroseparation, elecromigration, electrodialysis with UF membrane and electrophoresis membrane contactor as search subject in search engine “Web of science” to count all literatures in the field of EDPM. This technique was first published in 2000. In the following seven years, the number of published papers is relatively stable but small, with an average of 1–2 per year. The number of publicly published reports starts to rise steadily from 2008, and until 2015, the number of articles published on average was maintained 3–4 per year. The number of publications published between 2016 and 2019 has further increased. These indicate the increasing number of studies in this new technology in the last two decades. In addition, Professor Laurent Bazinet's research groups from Canada are the leader in this field, and they come from Institute of Nutrition and Functional Foods (INAF), Dairy Science and Technology Research Centre and Department of Food Sciences and Laboratory of Food Processing and ElectroMembrane Processes (LTAPEM) of Université Laval.They make significant contributions to the study of EDPM technology.

The aim of this review is to provide a summary of the characteristics and recent development of EDPM process. The relevant literatures regarding this technology in recent years are listed and some representative case studies discussed. The basic principle and configuration of EDPM processing are provided first. A number of other separation technologies based on electrophoresis with similar cell configuration to EDPM are presented and discussed. The performance optimization of process and the membrane fouling phenomenon during the treatment are also discussed. Finally, different applications of EDPM technology especially in the separation of functional components are summarized in detail. This review has narrated, for the first time, a relatively comprehensive current state of EDPM technology in as much detail as possible. Hopefully to supply some viewpoints for prospective developments in EDPM technology.