Production of fungal extracellular immune stimulating compounds

摘要

A process is described for the production of an immunostimulant by submerged cultivation of Ganoderma lucidum in which mycelium from agar plates or a fermentation broth is added to a liquid medium in a shake flask or a bioreactor containing nutrients such as malt extract, yeast extract, peptone and glucose having access to air or to which air is added, and which is kept in constant movement at approx. 28° C. At the proper conditions, there will be an increase in the production of extracellular lentinan, which is shown to be a better immunostimulant than intracellular lentinan. The extracellular product is precipitated from the growth medium by means of methods for the precipitation of microbial polysaccharide.

主权项

1. A method for producing one or more water-soluble extracellular immune stimulating agents, said method comprising the steps of:
i) cultivating the fungus of the genus Ganoderma lucidum in an aqueous liquid growth medium, wherein said cultivation results in accumulation of said one or more immune stimulating agents in the aqueous growth medium, ii) separating the fungal mycelium from said aqueous liquid growth medium by centrifugation or filtration to obtain an aqueous phase supernatant comprising said one or more immune stimulating agents, and iii) subjecting said aqueous phase supernatant, or a fraction thereof, comprising said one or more water-soluble immune stimulating agents to at least one size fractionation step resulting in the isolation of an aqueous phase isolate which comprises one or more immune stimulating agents comprising a polysaccharide having a molecular weight in the size range of from 100,000 g/mol to 1,000,000 g/mol; wherein said aqueous phase supernatant comprising said one or more immune stimulating agents is not subjected to alcohol precipitation, and wherein said isolation of the aqueous phase isolate does not degrade or convert said immune stimulating agents during the isolation.