Methods for preparing a recombinant protein from a bacterium are provided. The method includes constructing an expression vector including two promoters. Each of the two promoters attaches a secretion signal peptide to one polypeptide of a protein. The protein attached with the two promoters and secretion signal peptides is then cloned into the expression vector to provide a recombinant expression plasmid. The recombinant expression plasmid is transformed into a host cell. A fermentation process is performed to grow the host cell and to induce an expression to synthesize polypeptides in the host cell and to transport the polypeptides to an outside of a cytoplasm of the host cell, such that the polypeptides are released in a soluble form in a growth medium of the host cell. The polypeptides are assembled into a three-dimensional structure of the protein. The protein is captured from the growth medium.

The present invention is drawn, in part, to biocompatible compositions comprising a biocompatible polymer matrix and conditioned cell medium comprising i) a cell culture medium and ii) one or more agents synthesized by and secreted from one or more cells cultured in the cell culture medium, as well as therapeutic uses thereof, particularly in modulating bone and/or gum tissue growth.

The invention relates to solid medium for producing glucosamine, including a substrate and 0.15-4.8 mL/g substrate of supplemental solution, which includes 0.1-2 g/L KH.sub.2PO.sub.4, 0.1-2 g/L NaCl, and 0.1-2 g/L MgSO.sub.4.7H.sub.2O. The invention also relates to a method for producing glucosamine, including providing microorganism being able to produce glucosamine, and fermenting the microorganism in the medium mentioned above.

Methods of culturing cells capable of producing desired proteins to obtain the proteins by use of a medium from which biological components are excluded as much as possible are provided. Specifically, a culture method characterized by culturing while maintaining a specific amino acid in a culture solution at a high concentration, and a cell culture fed-batch medium for use in the method are provided.

Cell culture media, preservative media or cryopreservation media include a low dose of one or more cytokines, e.g. interleukin-2 (IL-2).

Described herein is an egg yolk extract comprising freed/lysed yolk granules and/or yolk spheres. Also described is an egg yolk extract comprising the liquid contents of a shelled egg, wherein the liquid contents comprise yolk granules. Also described are an egg yolk extract comprising the liquid contents of yolk spheres; an egg yolk extract comprising the liquid contents of yolk granules; an egg yolk extract comprising ovalbumin and other anti-bactericidal proteins in egg white; and an egg yolk extract that supports cell proliferation at least equivalent to FBS when used at the same concentration in a cell culture medium. Related supplements, media, and methods are also described.

Methods and systems of harvesting a cell product from a cell culture by culturing cells in a fluid medium until the cells have produced a cell product at a harvest concentration are disclosed. The cells are cultured in a cell culture system including a bioreactor connected to an ATF device. The methods include draining fluid medium from the bioreactor through the outlet and the ATF device until the bioreactor volume reaches a predetermined volume, and the ATF column yields at an ATF outlet a liquid containing cell product and passes fluid medium with a concentration of cell product that is lower than the harvest concentration back into the bioreactor, extracting the liquid containing cell product from the ATF outlet, refilling the bioreactor with sterile phosphate buffered saline or fluid medium without any cell product, and repeating steps until a desired amount of cell product has been removed.

Provided herein are methods of freezing mammalian cells for storage or improving thaw recovery of cell banks comprising freezing mammalian cells in a freezing medium having a pH of 6.7 to 8.5.

Delivering a payload across a plasma membrane of a cell includes providing a population of cells and contacting the population of cells with a volume of an aqueous solution. The aqueous solution includes the payload and alcohol content greater than 5 percent concentration. The volume of the aqueous solution may be a function of exposed surface area of the population of cells, or may be a function of a number of cells in the population of cells. Related compositions, apparatus, systems, techniques, and articles are also described.

Compositions, devices and methods are described for improving adhesion, attachment, and/or differentiation of cells in a microfluidic device or chip. In one embodiment, one or more ECM proteins are covalently coupled to the surface of a microchannel of a microfluidic device. The microfluidic devices can be stored or used immediately for culture and/or support of living cells such as mammalian cells, and/or for simulating a function of a tissue, e.g., a liver tissue, muscle tissue, etc. Extended adhesion and viability with sustained function over time is observed.