Solid state fermentation is a biomolecule manufacturing process used in the food, pharmaceutical, cosmetic, fuel and textile industries. These biomolecules are mostly metabolites generated by microorganisms grown on a solid support selected for this purpose. This technology for the culture of microorganisms is an alternative to liquid or submerged fermentation, used predominantly for industrial purposes Solid State Fermentation is a fermentation method used by several industries like the pharmaceuticals, food, textile etc. to produce metabolites of microorganisms using solid support in place of the liquid medium. Solid state fermentation has emerged as potential technology for the production of microbial products such as feed, fuel, food, industrial chemicals, and pharmaceutical products. The latter characteristic of SSF renders the measurement and control of the above mentioned parameters difficult, laborious and often inaccurate, thereby limiting the industrial potential of this technology. Due to these problems, the micro organisms that have been selected for SSF are more tolerant to a wide range of cultivation conditions. This book is summarizes the diversity of applications of solid state fermentation to valorize biomass regarding alternative energy and environmental purposes. The success of applying solid state fermentation to a specific process is affected by the nature of specific microorganisms and substrates.