Solid State Fermentation (SSF)

Fermentation in solid media... What a strange title for anyone unfamiliar with the subject! In the West, the term "fermentation" is associated with the production of liquid foodstuffs such as beer and wine, while products such as bread and cheese, which are produced by fermentation in a solid medium, are quickly forgotten. In the Far East, solid fermentations (such as the production of sake or tofu) go back a long way, and have been used for centuries to produce a number of staple foods in these countries. Sake also plays an important cultural role: it is the drink of the gods in the Shinto religion (the majority in Japan), and it would be unthinkable for them to modify the production process; just as it would be unthinkable in Christian societies to modify the production process for wine, the blood of Christ!

In natural environments, solid fermentations occur everywhere, in cultivated or uncultivated soils, in compost or silage. But the term "fermentation" is not naturally associated with what happens in these "open" environments. The term is reserved for more elaborate processes developed in the laboratory and implemented in bioreactors in "closed or regulated environments". Fermentations are associated with biotechnologies and, in our industries, are essentially liquid-based processes.

With the world's population on the rise and energy requirements on the increase, food and arable land are a vital economic issue for mankind! In emerging countries, the development of solid-state fermentations using foodstuffs would go some way to alleviating the enormous losses of fresh produce, which is difficult to preserve using heat. In fact, fermented products have the advantage of increasing the shelf life of a product compared with the raw material, and also improve the nutritional qualities of the product. What's more, these processes require little energy and simple production equipment, such as that developed by the IRD in Marseille . In industrialized countries, fermented products (resulting from these fermentations) are becoming increasingly popular with consumers, who are rediscovering their health benefits.

But solid-phase processes are also enjoying a revival in the West, with the valorization of agricultural by-products for the production of enzymes, animal feed and, more recently, for the production of organic products, and more generally are involved in processes for the valorization of plant biomass. These new developments are encouraging investment in this...