The present invention relates to a method for continuous recovering of a protein from a fluid, comprising precipitating the protein in the fluid and separating the precipitated protein from the fluid. The invention also provides an inclined plate settler that can be used for such continuous protein recovering.

A method is provided for extraction of fine silk fibroin powder from Bombyx mori silk cocoons. The conventional method of silk processing includes dissolution of the degummed silk fibers in some strong salt solutions followed by a dialysis step. The earlier reported strong salt solutions have either associated environment issues or lower dissolution ability for silk. However, the provided method includes degumming silk cocoons, drying and cutting the degummed silk fibers, mixing the fibers with an ionic liquid, stirring the mixture, regeneration of silk from the mixture with the help of an anti-solvent followed by centrifugation, drying the precipitated silk and finally obtaining a fine powder of silk.

In certain embodiments, the present invention provides novel antibody purification methods and systems using a potentially simple and cost-efficient means. In some embodiments, customized Z-33 derived from Staphylococcus aureus Protein A is used to construct immuno-amphiphile molecules which can assemble into immunofibers in aqueous solution with bioactive epitopes on the surface and have IgG binding ability.

Tetrameric N-terminally acetylated α-synuclein is prepared by transforming an expression system with an expression vector encoding α-synuclein, wherein the expression system expresses a native NatB acetylase complex or ortholog thereof and/or wherein an exogenous NatB acetylase complex or ortholog thereof is co-expressed in the expression system, inducing protein expression in the transformed expression system, lysing cells in the transformed expression system to produce a cell lysate, performing salt precipitation of the cell lysate, recovering tetrameric N-terminally acetylated α-synuclein by centrifugation, and purifying the tetrameric N-terminally acetylated α-synuclein. Compositions comprising the same and methods for identifying compounds that stabilize natively folded tetrameric α-synuclein are also provided.

Compositions and methods for the isolation of protein-nucleic acid complexes and microvesicles (collectively referred to as “bioparticles”) released by mammalian cells into body fluids or cell culture media are provided. Isolated bioparticles of the invention contain biological molecules that are useful as diagnostic/prognostic biomarkers or for identification of therapeutic targets (e.g., disease or disorder-associated miRNAs). The isolation of biological molecules as described herein results in purification and concentration of the molecules. Methods for producing bio fluids that are free of detectable bioparticles, that are largely depleted of bioparticles, or that possess a reduced concentration of bioparticles compared to a bio fluid starting material (collectively termed “bioparticle-depleted”) are also provided. Isolation of bioparticle-depleted biofluid is useful, e.g., in experimental systems where it is desirable to use a biofluid that does not contain endogenous bioparticles, or has been substantially depleted of endogenous bioparticles, from the source material.

Methods are provided for isolation of immunoglobulin G (IgG) from plasma, where IgG is initially fractioned by salt precipitation, followed by successive ion exchange steps in which IgG appears in unbound, flow-through fractions of the ion exchange steps. Some embodiments employ successive anion exchange steps. Other embodiments employ an anion exchange step followed by application of flow-through of the anion exchange step to a cation exchange step, with IgG collected in flow-through fractions from the cation exchange step. IgG is collected at high yield (typically about 75% or greater) and high purity. Avoidance of binding and elution from chromatography media simplifies processing and scale up without sacrificing IgG quality or yield.

In certain embodiments, the present invention provides novel antibody purification methods and systems using a potentially simple and cost-efficient means. In some embodiments, customized Z-33 derived from Staphylococcus aureus Protein A is used to construct immuno-amphiphile molecules which can assemble into immunofibers in aqueous solution with bioactive epitopes on the surface and have IgG binding ability.

Methods for isolating proteins from solution by precipitation and compositions generated thereby are provided. A nonvolatile precipitation agent is added to an aqueous protein solution at a low concentration. Water is then removed from the resulting solution until the precipitant and the protein content of the solution increase to a concentration that provides the desired segregation of proteins between supernatant and precipitate. Additional water can be removed from the supernatant to provide additional fractionation. Water can be removed by evaporation (e.g. under reduced pressure) and/or diafiltration.

The present invention relates to an improved process for the synthesis of Etelcalcetide and its analogs by solid phase synthesis of Fmoc protected amino acids in a sequential manner, followed by acetylation of terminal D-cys and cleavage of peptide from solid support. The crude heptapeptide thus obtained is reduced using Tris(2-carboxyethyl) phosphine hydrochloride, purified and oxidized with L-cysteine. The oxidized Etelcalcetide is purified and salt exchanged using a one-step reverse phase chromatography process. The purified Etelcalcetide hydrochloride is then precipitated using organic solvents, concentrated and lyophilized to purity of greater than 99.0%.

A method for purifying phycocyanin from a phycocyanin-containing solution is provided. The method comprises a first step of partially purifying the solution by aqueous two-phase separation (ATPS) and a second step of purifying the phycocyanin by ammonium sulfate precipitation. The purified phycocyanin product can in some cases be of a sufficiently pure grade to be used as a food or cosmetic pigment.