Current Trends and Future Developments on (Bio-) Membranes

Membrane Processes in the Pharmaceutical and Biotechnological Field

Angelo Basile, Catherine Charcosset

• Publisher: Elsevier
• Year: 2018
• ISBN:
  9780128136072
• Topic: Biological Sciences
• Subtopic: Biophysics
• Index: Biological Sciences

Current Trends and Future Developments on (Bio-) Membranes: Membrane Processes in the Pharmaceutical and Biotechnological field presents the main membrane techniques along with their basic principles, mode of operations, and applications. It covers well-known techniques such as ultrafiltration and membrane chromatography, while also exploring emerging membrane technologies which are finding their way in pharmaceutical and biotechnology industries, including membrane emulsification, membrane bioreactors, and solvent-resistant nanofiltration. State-of-the-art applications of membrane systems in areas such as drug delivery and virus removal are also investigated by leading experts in the field.

Current Trends and Future Developments on (Bio-) Membranes: Membrane Processes in the Pharmaceutical and Biotechnological field is a definitive reference for academics, post-graduates, and researchers in the subjects of biochemical engineering, pharmaceutics, and biotechnology. It is also useful to R&D companies and institutions in these areas, specifically those interested in bioseparations, biopurification, bioproduction, and drug delivery.

• Offers an overview of classical membrane-based separation techniques such as ultrafiltration, microfiltration and virus filtration
• Discusses emerging membrane-based separation techniques such as nofiltration in the presence of solvent, membrane emulsification and membrane crystallization
• Outlines their applications to bioseparation, biopurification and bioproduction
• Includes examples in the production of vaccines, antibiotics, biomolecules, drugs, DNA and cells
• Lists membranes systems for drug delivery like liposomes, nanocapsules and bilayer membranes

Chapter 1

Ultra- and Microfiltration in Dairy Technology

Ulrich Kulozik Technical University of Munich, Munich, Germany

Abstract

This chapter focuses on novel applications of ultra- and microfiltration in dairy technology, alone or in cascade mode, partially in combination with reverse osmosis and nanofiltration. Progress is reported on a better understanding of the phenomenon of deposit formation of proteins on membrane surfaces. Ways to minimize this effect and, thus, to improve filtration flux and transmission are demonstrated.

Keywords

Milk protein fractionation; Diafiltration; ESL milk; Membrane cascade; Dynamic membranes; Gradient membranes; Deposit formation; Membrane fouling; Reverse osmosis

Abbreviations

ATF alternating tangential flow

BSA blood serum albumin

CFF crossflow filtration

cfu colony forming units

DF diafiltration

ESL extended shelf life

La lactalbumin

Lg lactoglobulin

MF microfiltration

N number

nps nominal pore size (m or Da (Dalton))

RO reverse osmosis

TFF tangential flow filtration

UF ultrafiltration

UTP uniform transmembrane pressure

VRR volume reduction ratio

w/w weight/weight

WPC whey protein concentrate

WPI whey protein isolate

WPP whey protein powder

ZrO₂ zirkonium oxide

Abbreviations and Formula Symbols

C₀ starting concentration
g/L

C_DF concentration after diafiltration
g/L

c_per concentration in the permeate
g/L

c_ret concentration in the retentate
g/L

Δp_Deposit pressure loss in the deposited layer
Pa

Δp_TM transmembrane Pressure
Pa

η dynamic viscosity
Pas

θ temperature
°C

J specific flux
L/(m²h)

L length
m

p pressure
Pa

p_in inlet pressure
Pa

p_out outlet pressure
Pa

p_per pressure on the permeate side
Pa

p_ret pressure on the retentate side
Pa

R_D filtration resistance of the deposit
m^{− 1}

R_M filtration resistance of the membrane
m^{− 1}

τ_w wall shear stress
Pa

1 Introduction

Following the introduction of homogeneous, pore-free reverse osmosis membranes (RO) in the 1960s, membranes with a porous structure were the second generation in pressure-driven membrane technology. The first RO applications were in the field of seawater desalination to produce potable water. Later, RO was applied to remove water from liquid foods as alternative or supplementation of evaporation. Ultrafiltration (UF) was first introduced in food technology in New Zealand in the 1970s. The application was the concentration of proteins contained in whey to produce whey protein concentrates (WPCs), even when dried after the concentration step, which should be named whey protein powders, WPP. This offered a new way for making commercially added value use of the huge amounts of whey, which previously had been exclusively used as animal feed, if not drained into the environment. Together with lactose production, this greatly reduced the environmental impact of cheese manufacture.

Later on, microfiltration (MF) was introduced, once the manufacturing procedures for more open porous membranes with more or less defined nominal pore sizes with robust specification were controlled. The most prominent and main application of MF at first was the reduction of microbial load with the objective to preserve milk, possibly even without thermal treatment. While this challenging aim has not been reached, partially due to regulatory food safety issues, microfiltration has been successfully integrated in the production of milk with a longer (extended) shelf life (ESL milk) than traditional drinking milk, combined with traditional pasteurization (72°C/20 s). Another very interesting and commercially successful application of MF in the area of dairy technology emerged when it was shown that proteins of different sizes could be separated without chemical or thermal impact (Kulozik and Kersten, 2001, 2002). This allows the obtaining of native casein micelles as retentate and native low molecular (“whey”) proteins from milk, i.e., without producing whey at first by conventional cheese technology.

In a similar way, membrane processes become increasingly integrated in a range of upstream and downstream technologies in biotechnological or pharmaceutical applications in the field of separation and purification/isolation of biogenic products derived from or produced by microbial fermentations or for cell concentration, e.g., in starter culture manufacture for fermented dairy and other foods.

Along with the development and commercial availability of a suitable membrane material with defined properties, the introduction of crossflow filtration (CFF) processing techniques has been another critical step in the application of membrane technologies in food technology. Macromolecular biogenic material such as proteins or polysaccharides, when concentrated by UF or MF membranes, tend to produce deposited layers similar to “filter cakes” on the membrane surfaces with high resistance R_D to filtration flow toward the membrane. This is despite the fact that deposited layer tend to be μm-thin as a result of wall shear stress in CFF. Thus, specific filtration flow (flux J) is restricted by the resistances of the membrane (R_M) and the deposit (R_D), as in Eq. (1).

$J=\mathrm{\Delta }{p}_{\mathrm{TM}}/\eta \left(R_{\mathrm{M}}+R_{\mathrm{D}}\right)$

(1)

with viscosity η of the aqueous phase.

Many applications would not have been efficient enough or commercially viable if the old conventional dead-end filtration technique had still been the only processing principle. CFF or tangential flow filtration (TFF) as the membrane surface with high fluid velocities introduces forces on the just depositing and already deposited material preventing deposition, thus avoiding excessive thicknesses of the deposited layers with exorbitant resistances to flow and undefined separation results.

When RO and UF/MF applications are compared, it is obvious that different permeation mechanisms or mass transportation principles apply. While RO membranes are considered pore-free, UF and MF membranes are openly structured like sponges with a more or less defined porosity, which can be controlled by the membrane manufacturing process within certain limits. This applies for ceramic membranes made of inorganic material such as silicium dioxide (SiO₂) of aluminum trioxide (Al₂O₃) and for polymeric membranes made of organic material such as polypropylene or polyethersulfone (and many others). The filtration and separation mechanism in RO technology is diffusional transport across the membrane, with water and solutes crossing the membranes independently from each other based on their individual diffusional mobilities in the membrane material. In contrast, the transportation mechanism through porous membranes occurs as laminar flow of the aqueous phase according to Hagen-Poiseuille’s law or Darcy's law. Solutes such as sugars or minerals fitting through the membrane pores are convectively transported by...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Contributors
• Preface
• Chapter 1: Ultra- and Microfiltration in Dairy Technology
• Chapter 2: Microfiltration in Pharmaceutics and Biotechnology
• Chapter 3: Virus Removal and Virus Purification
• Chapter 4: Nanofiltration in the Pharmaceutical and Biopharmaceutical Technology
• Chapter 5: Purification of New Biologicals Using Membrane-Based Processes
• Chapter 6: Membrane Chromatography for Biomolecule Purification
• Chapter 7: Membrane Emulsification in Pharmaceutics and Biotechnology
• Chapter 8: Applications of Membrane Bioreactors in Biotechnology Processes
• Chapter 9: Supported Liquid Membranes in Pharmaceutics and Biotechnology
• Chapter 10: Drug Delivery With Membranes Systems
• Chapter 11: Lipid Membrane Models for Biomembrane Properties’ Investigation
• Index