ABSTRACT

Fermentation is traditionally a process which enables to preserve food and as such has been used for centuries until present. Fermentation processes utilize microorganisms to convert solid or liquid substrates into various products. Most commercially useful fermentations may be classified as either solid-state or submerged cultures. Solid-state and submerged fermentations may each be subdivided-into oxygen-requiring aerobic processes, and anaerobic processes that must be conducted in the absence of oxygen. An understanding of fermentation biotechnology is essential for developing a medium with an appropriate formulation. The O2 requirements of a fermentation depend on the microbial species, the concentration of cells, and the type of substrate. A fermenter must provide for heat transfer during sterilization and subsequent cooling, as well as removing metabolic heat. Solid-state (substrate) fermentation (SSF) has been defined as the fermentation process occurring in the absence or near-absence of free water. SSF processes generally employ a natural raw material as carbon and energy source.