Membrane Filtration is a separation process which divides a liquid solution by means of a semi-permeable membrane. The separation occurs when a driving force is applied across the membrane, resulting in two separated solutions known as the permeate and retentate. By utilizing different pore sizes, membrane filters can either concentrate or reduce specific components in the liquid solution. This separation technology has been employed by many industries worldwide, with two prominent examples seen in the dairy and biotechnology industries. –
Dairy Industry –
The world’s dairy industry is an integral part of the global economy and food supply chain, with well over 200 million tons of cheese produced daily. However, only about 10 percent of the milk used in cheese production actually ends up in cheese, with the resulting byproduct consisting of mostly proteins, lactose, minerals, and water. Membrane filtration has become a vital solution to processing this byproduct volume and is used in several applications such as whey protein concentration. During this process, microfiltration elements are utilized to screen bacteria and other unwanted microbes in the milk. Ultrafiltration elements are then employed to increase the protein content, capable of achieving ultra pure whey protein isolates (WPI) in the 90th percentile range. After the protein is concentrated and removed, the remaining solution can be sent to nanofiltration membranes for concentration or demineralization of lactose. By concentrating and demineralizing these byproducts, the dairy industry is able to reduce liquids previously discharged to waste, while also bolstering their product offerings to consumers. In fact, many precursors to popular fermented milk products such as yogurt, kefir, and sour cream are produced through these membrane filtration processes.
Biotechnology Industry –
Membrane filtration has always held a critical role in various biotechnology processes. The sterile filtration of fermentation media, removal of endotoxins, and recapturing of free enzymes are standard practice in industry. Membrane filters can be utilized in virtually all biotechnology processes, with a considerable number of mammalian cell processes using filtration as an integral part of their sterilization strategy. The high through put and relatively low operational costs associated with membrane filters are one of the economical reasons why they have been standardized in many biotech applications. Ultrafiltration membranes have become the method of choice for protein concentration and buffer exchanges, replacing traditional methods such as size-exclusion chromatography and centrifugation. Membrane filters have also become a popular choice among industrial enzyme manufacturing lines to concentrate the enzymes before further downstream processing. As improvements in membrane technology continue to advance, membrane filters can be expected to play a critical role in the next generation of biotechnology processes.