Tangential flow filtration (TFF) is widely used in biopharmaceutical processing for protein purification – a common application for TFF is ultrafiltration for concentration/diafiltration of proteins. In this type of application, the product protein is retained (concentrated) within the feed side of the ultrafiltration membrane, while the buffer components and other small impurities (smaller than the membrane pore size) freely pass through the membrane into the permeate side. Several scholarly articles are available in literature which discuss the ultrafiltration application as well as its optimization strategies. Another category of application where TFF finds significant use is in the clarification of cell culture bioreactor and microbial fermenter feed solutions using microfiltration membranes. In some of these microfiltration TFF applications (e.g., mammalian cell culture clarification), the product (protein) freely passes through the microfiltration membrane and is recovered on the permeate side, while the contaminating impurities (cells, cell debris, colloids) are retained on the feed side of the membrane. In certain other microfiltration TFF applications (allantoic fluid clarification in egg-based flu process), the product (flu virus) may get concentrated on the feed side of the microfiltration membrane (similar to an ultrafiltration step), while the contaminating impurities (ovalbumin, etc.) may get removed into the permeate side…
Tag: <span>tff</span>
Nematode worms release pheromones to communicate information about food, stress, and sex to other individuals. The nematode species C. elegans is a genetic system for studying the biology underlying these pheromone-mediated behaviors. Identifying the chemical structure of C. elegans pheromones requires purifying them directly from large quantities of conditioned growth media. Release of pheromones may depend on growth conditions, population density, and developmental stage. However, published studies only report nematode pheromones from developmentally asynchronous cultures at variable population densities. Here, we have developed reliable methods for liquid culture of developmentally-synchronous populations of C. elegans at controlled population densities from 5,000 to 10,000 worms/mL at the scale of 10 to 100 L. Generating synchronous populations requires harvesting eggs from adults using alkaline bleach. In this study, we developed modified tangential flow filtration (TFF) systems to rapidly bleach adults and recover large quantities of healthy, viable eggs. This method achieved synchronous cultures at scales 2.5 x greater than cultures based on agar plates, and 5 x greater than previously reported for synchronous liquid cultures. We routinely harvested 2.5 x 10E7 animals (total) from a single 5 L large-scale culture. Furthermore, our TFF system effectively recovered pheromone-containing media at all scales tested. This work makes it feasible to isolate other biologically useful secreted molecules from transgenic C. elegans…
Tangential flow filtration (TFF) microfiltration has been used as one of the choices for clarification of mammalian cell or microbial cell culture in the biopharmaceutical industry. Unlike the ultrafiltration process for protein concentration and the diafiltration application where the feed solution is relatively clean (free of colloids or larger particles after the clarification/purification process), the microfiltration process needs to handle a rather high-fouling feed stream such as cells, cell debris, colloids, etc. In a previously published article, we discussed that a TFF microfiltration step is limited by a maximum throughput or capacity obtainable under a given set of operating conditions. Some distinct microfiltration characteristics, such as critical permeate flux, permeate flux control, and maximum throughput were explained in that article…