Biosepra® SPEC 70 SLS

Synthetic Ion Exchange Sorbent
for Dairy Protein Separations

Pall Biosepra SPEC 70 SLS ion exchanger sorbent is a spherical semi-rigid microbead of an acrylic copolymer designed for the ion exchange chromatography of proteins. The beads generate low back pressure at typical low pressure liquid chromatography process flow rates. The strongly bound ion exchange groups, which are an integral part of the polymer structure, constitute a three dimensional structure. Each sub-unit of the polymer possesses hydrophilic groups, which ensure biocompatibility and prevent non-specific adsorption.

SPEC 70 SLS ion exchangers are macroporous, the ion exchange groups are easily accessible, and the sorbent provides high capacity for proteins. Industrial applications currently at production scale includes purification. SPEC 70 SLS has been widely used for the production of LP/LF from milk or sweet whey at 1,500 – 2,000 L scale for more than 20 years and is approved by the FDA for the use with a Food Contact Substance (Food Contact Notification (FCN) number : 000325).

Features

Synthetic polymeric sorbent for process chromatography of proteins

• Highly hydrophilic and resistant to micro-organisms
• Macroporous polymer allowing large mass transfers
• Proven biocompatibility, designed to avoid non-specific adsorptions
• Many references for Lactoferrin (LF) and Lactoperoxydase (LD) production at industrial scale

SPEC 70 SLS was previously designed to be used in fluidized/batch mode but it can be used in packed bed mode. The sample (milk or sweet whey) is injected through the previously equilibrated chromatography sorbent. Proteins with an isoelectric point lower than the equilibration buffer pH come out of the column in the effluent while the others are adsorbed. The elution of adsorbed molecules is performed by a sodium chloride gradient. Proteins are separately desorbed and collected.

SPEC 70 SLS can be used as a capture step to bind the Lactoferrin and Lactoperoxydase that will be eluted together or as a separation step, LF and LP are eluted by steps of different salt concentration.

The sorbent is then regenerated with a high salt concentration solution (1 - 2 M sodium chloride) and, if necessary, washed with a cleaning solution such as NaOH. On a large scale, the design of the sorbent allows flux of 25,000 to 50,000 L/h of sweet whey with a residence time in the column from 2 to 8 minutes which allows to protect the biological activities of the proteins.

SPEC 70 SLS is an acrylic copolymer bead with a diameter between 260 and 600 μm. The polymer is very macroporous and allows a large surface contact and efficient mass transfer. The macromolecules diffuse easily from the outside to inside of the beads.

The active chemical group is sulfopropyl that is ionized upon the pH or ionic strength conditions and adsorbs molecules electrically charged with the opposite signs.

Properties

Particle size (μm)	260 - 600
Exclusion limit (dt)1	107
Nature of ionizable groups	Sulfopropyl
Amount of ionic groups (μEq/mL)	400 - 700
Binding capacity	Lactoperoxydase2: > 40 mg/mL Lactoferrin3: > 20 mg/mL
Working pH	4 - 13
Cleaning pH	1 - 14
Chemical stability (detergent)	Excellent
Microbial stability	Excellent
CAS number	388567-01-9
FCN number	000325

Chemical Stability

• SPEC 70 SLS sorbent is not modified by the commonly used solvents and NaOH.

Microbial Stability

• SPEC 70 SLS sorbent is resistant to microbial degradation. 

Thermal Stability and Storage

• Temperature of use: 2 - 30 °C (36 - 86 °F)
• Shipping temperature: 2 - 30 °C (36 - 86 °F)
• Storage temperature: 2 - 30 °C (36 - 86 °F) 2 - 8 °C (36 - 46 °F) once opened
• Recommended storage solution: Neutral buffer containing 0.5M NaCl and 20% (v/v) ethanol

¹ For globular proteins
² Determined using 5 mg/mL lactoperoxydase solution in 0.05 M sodium acetate, pH 5.5 ; elution with 10% NaCl ; column 16mm ID x 200mm
³ Determined using 2.5 mg/mL lactoferrin solution in 0.05 M sodium acetate, pH 5.5 ; elution with 10% NaCl ; column 16mm ID x 200mm