Process for producing single-cell protein from methanol using methylomonas sp. DSM 580

A process for the production of single-cell protein from methanol, which comprises placing, in an aerated fermenter with or without a mechanical stirrer, a growing submerged culture of the obligate methanol-utilizing bacterium Methylomonas sp. DSM 580, produced under aerobic conditions, cultivating it in the presence of methanol, used as the sole source of carbon and energy, and mineral salts, in the presence or absence of growth promoting agents, this system further provided with air or oxygen enriched air at a cultivating temperature from 20.degree. to 45.degree. C, thereafter removing the cell mass out of the three phase system and drying, resulting in a biomass with a crude protein content of at least 60-76% (w/w), a nucleic acid content of 2-17% (w/w), an ash content of 4-6% (w/w), a lipid content of 3-8 (w/w), the culture fluid, after removing the cell mass, is capable of being, at least partially, recycled.