Dharmesh M. Kanani

Natrix Separations Inc · Process Science

In almost all the dairy applications, ultrafilteration (UF) membranes are used to remove water, lactose, and mineral salt while retaining proteins. UF is a size-based separation process and its performance is typically measured through selectivity and flux. The flux in the UF process depends on the membrane properties, solvent properties, transmemb...

Protein A chromatography is widely employed for the capture and purification of monoclonal antibodies (mAbs). Because of the high cost of protein A resins, there is a significant economic driving force to seek new downstream processing strategies. Membrane chromatography has emerged as a promising alternative to conventional resin based column chro...

Dextran sieving (or retention) tests have become a standard method for characterizing the pore size distribution of ultrafiltration membranes. The objective of this work was to extend this methodology to the analysis of parvovirus filtration membranes with much larger pore size than traditional ultrafiltration membranes. Experiments were performed...

Recent advances in cell culture technology have created significant pressure on the downstream purification process, leading to a "downstream bottleneck" in the production of recombinant therapeutic proteins for the treatment of cancer, genetic disorders, and cardiovascular disease. Countercurrent tangential chromatography overcomes many of the lim...

The inference of the surface charge of polyethylene glycol (PEG)-coated and uncoated silicon membranes with nanoscale pore sizes from streaming potential measurements in the presence of finite electric double layer (EDL) effects is studied theoretically and experimentally. The developed theoretical model for inferring the pore wall surface charge d...

The effects of pore size on the performance of ultrafiltration membranes are fairly well understood, but there is currently no information on the impact of pore geometry on the trade-off between the selectivity and permeability for membranes with pore size below 100 nm. Experimental data are presented for both commercial ultrafiltration membranes a...

A rapid characterization method was used to study protein fouling of cellulose acetate membrane during dead-end, in-line, constant flux microfiltration. Based on pressure-permeate volume profiles, two fouling phases could be identified and compared at different permeate fluxes. Using protein staining dyes, the model foulant (bovine serum albumin) w...

In-line microfiltration which is widely used for sterilization of therapeutic proteins prior to formulation is frequently operated at constant flux by pumping purified protein solution through a membrane. Increase in transmembrane pressure (TMP) due to membrane fouling is a major problem in such processes. This study examines how resistance to filt...

This paper discusses the separation of human serum albumin (HSA), the most abundant protein present in plasma from human immunoglobulin G (HIgG) by membrane chromatography using a novel macroporous gel-filled membrane (designated Q Type 2). The membrane was prepared by anchoring a quaternary ammonium salt macroporous gel within the pores of a non-w...

This paper discusses a novel approach for predicting permeate flux decline in constant pressure ultrafiltration of protein solutions. A constant pressure process is assumed to be made up of a large number of small, sequential, constant flux ultrafiltration steps: the flux decreasing due to fouling and other related factors at the end of each step....

We describe a rapid, inexpensive and scalable hybrid bioseparation technique for one-step purification of humanized monoclonal antibodies from mammalian cell culture supernatant. It involves the selective and reversible retention of the monoclonal antibody within a membrane module utilizing a combination of microfiltration of precipitated antibody...

This paper discusses a novel approach based on the use of the protein BSA as a dual-facilitating agent for manipulating the separation of two model proteins having comparable molecular weights. When a binary mixture of lysozyme and myoglobin alone was ultrafiltered, lysozyme was transmitted through the membrane to a substantially greater extent tha...

The use of polyelectrolyte gel coated adsorptive membranes for protein bioseparation by membrane chromatography was discussed. The protein binding capacity of the polyelectrolyte gel-coated, ion-exchange membrane was significantly higher than that reported in literature. The results show that in the pH range, 5.5-7.5, dynamic adsorption of human se...

The present work describes the possibility of using pervaporation to recover the tea aroma compounds from tea aroma condensate generated in the manufacturing of tea or instant tea, as well as directly from tea extract. Eight compounds that make a significant contribution to tea aroma, namely, trans-2-hexenal, linalool, cis-3-hexenol, 3-methylbutana...

Cost-effective large-scale protein bioseparation will be the key issue for the biopharmaceutical industry in the coming years. Conventional protein purification techniques are severely limited in the sense that they give either good selectivity of separation at the cost of throughput or vice versa. Synthetic membrane based bioseparation techniques...