Enzyme and Protein Filtration and Processing

GEA Filtration and Enzyme Processing

Brief on subjects related to the processing of proteins / enzymes using cross flow membrane filtration

Microfiltration (MF) for the recovery of proteins / enzymes

After extensive on site pilot testing, GEA Filtration have recently designed and supplied two large systems combining ceramic Microfiltration (MF) and spiral Ultrafiltration (UF) to harvest the cells and recover enzymes. In both cases, these are pseudomonas bacterial broths, one being whole cells and the other being supernatant from a centrifuge. Both systems include TAMI ceramic membranes, one with 0.45 micron, 6 mm diameter and the other using 0.14 micron Isoflux, 4 mm.

Control of Trans Membrane Pressure (TMP)

When recovering enzyme and protein from a fermentation broth, the permeability and the flux can be influenced by:

Highly automated GEA Filtration pilot plant Model T for ceramic membrane screening

• Interaction between the membrane surface and the product, nutrients or other species e.g. antifoam
• Ionic strength and pH
• Formation of a gel polarization layer

The first issue can be addressed by membrane choice and possible changes to antifoam choice, the second by controlling ionic strength.

Gel polarization layer is influenced by the nature of the feed and conditions at the membrane surface. A pre clarified broth will tend to form a much denser gel layer and hence flux rates and permeability will tend to be reduced.

Not only is the gel layer more open when processing whole broth the solids themselves probably promote turbulence close to the membrane surface.

By use of the Isoflux membrane with permeate pressure control it is possible to separate and optimize individually the influences transmembrane velocity and trans membrane pressure whilst achieving similar levels of flux over the entire membrane surface in a simple and reliable manner. Membrane performance using this approach will be enhanced as will the reliability of the plant.

In one of the recent cases, in which GEA Filtration applied TAMI's Isoflux membrane, the result was close to twice the flux rate compared to a standard 0.1 or 0.2 micron ceramic membrane.

Harvesting of fungal broths and yeasts

Rendering of a commercial size ceramic microfiltration (MF) plant

GEA Filtration has also been successful in harvesting fungal broths to clarify the penicillin. Fungal broths are more fouling than either bacterial or yeast cell broths but Microfiltration is still effective in clarifying the broth. Yeast broths are typically large cells and relatively easy to harvest with Microfiltration.

Microfiltration cost effective

While the economics of every company's process needs to be evaluated closely, ceramic MF has proven to be both cost-effective and technically capable of harvesting the cells and recovering enzymes. The cost-effectiveness is due to higher yields and cleaner, sharper separation compared to traditional separation technology like centrifuges or rotary vacuum filters and filter presses. Therefore, it is worth the while pilot testing ceramic MF to witness the benefits first hand.

Ultrafiltration (UF), spirals

GEA Filtration multipurpose pilot pant Model R for screening of ceramic and spiral membranes in the microfiltration (MF), ultrafiltration (UF), nanofiltration (NF), and reverse osmosis (RO) ranges.

The key to success with spiral systems is to ensure the suspended cell solids are very fine and low in concentration or have been completely removed. In either case, spiral UF can be an attractive alternative for the concentration and / or purification of antibiotics and proteins due to the high area to plant volume ratio and small hold up volume.

Spiral wound membranes are today available with much improved pH and temperature stability and are available in a wide range of pore sizes and membrane types.

Being polymeric in nature the membrane performance will be strongly influenced by the pH and ionic strength of the feed stream in combination with the membrane characteristics.

NF / RO spirals

In many cases the permeate obtained when concentrating products by Ultrafiltration contains valuable by-products which can be recovered by Nanofiltration or Reverse Osmosis membranes and the permeate recovered in this process used as diafiltration water back in the recovery step thereby reducing utility consumption.

The Company

GEA Filtration is a world leader in crossflow membrane filtration, with reverse osmosis and nano-, ultra- and microfiltration as core technologies. GEA Filtration is part of the GEA group and has application centers in the USA, Australia, New Zealand, Germany, and Denmark.

GEA Filtration pilot plant Model R-xp - Engineered and built to NEC Class 1, Division I, Group C and D hazardous area construction standards. This construction allows for testing of membrane filtration applications that employ non-water based solvent systems having potentially explosive characteristics.