Preparation of GM1 ganglioside with sialidase-producing marine bacteria as a microbial biocatalyst

This paper describes the preparation of monosialoganglioside GM1 with sialidase-producing marine bacteria as a microbial biocatalyst. A new sialidase-producing bacterium, identified tentatively as Pseudomonas sp, strain YF-2, was isolated from seawater by enrichment culture with ganglioside as the sole source of carbon, When YF-2 was cultured in a synthetic medium containing crude bovine brain gangliosides at 25 degrees C for 3 days, 80 to 90% of the gangliosides were converted to GM1, GM1 was then purified from the supernatant of YF-2 culture by C-18 reverse-phased chromatography, followed by DEAE-Sephadex A25 anion-exchange chromatography, In a typical experiment, 178 mg of highly purified GM1 was obtained from 500 mg of the crude ganglioside fraction, The GM1 induced neurite outgrowth of neuroblastoma Neuro2a cells at a concentration of 33 to 100 mu M in the presence of fetal calf serum, Sialidase was purified 33-fold with 13.3% recovery from the culture supernatant of YF-2. The purified enzyme hydrolyzed polysialogangliosides to produce GM1 but did not act on GM1. It was therefore concluded that polysialogangliosides in the culture of strain YF-2 were converted to GM1 by this sialidase.