Abstract: Provided is a method for the production of single cell protein (SCP) comprising anaerobic fermentation of Clostridia bacterium on a fermentation medium comprising a gas, wherein said gas provides a source of energy and carbon for said bacterium. Further provided is a single cell protein produced by the method as disclosed herein.

Abstract: Producing a composition comprising cells of at least one bacterium, where at least 90% of the composition is in the form of a free flowing powder, by providing a drum dryer comprising two spaced-apart rotatable cylinders, with a gap of width G inches and a length of L inches therebetween; providing a fermentation broth comprising cells of at least one bacterium in a liquid suspension at a total solid content C percent weight of no greater than about 15% wt of the total weight of the fermentation broth; and introducing the fermentation broth into said drum dryer at a rate of W Kg per hour of no greater than 14×[(G×L)/C] to provide the composition.

Abstract: A process for producing at least one polyhydroxyalkanoate through gas fermentation may include: providing at least one gas fermentation vessel having a volume partially filled with a liquid fermentation broth that includes: water, suspended gas-fermenting microorganisms capable of producing the at least one polyhydroxyalkanoate, and nutrients for the gas-fermenting microorganisms, a remaining part of the volume of the at least one gas fermentation vessel being filled with a gas phase; continuously withdrawing an aliquot of the liquid fermentation broth from the at least one gas fermentation vessel; supplying a gaseous substrate comprising CO2, H2, and O2; cultivating the gas-fermenting microorganisms to form a cell mass containing the at least one polyhydroxyalkanoate; and recovering the at least one polyhydroxyalkanoate from the cell mass.