Innovative Production of Bioproducts From Organic Waste Through Solid-State Fermentation

Solid-state fermentation (SSF) is, by definition, a technology carried out in the absence or near absence of free water. Therefore, it allows the use of solid materials as substrates for further biotransformation. SSF has gained attention in the last years, being reported as a promising eco-technology to produce bioproducts of industrial interest using solid biomass (wastes and by-products). Main advantages over conventional submerged fermentation rely on the lower water use and energy requirements,which generates minimum residual streams. However, drawbacks often appear,related to poor homogeneity and energy and mass transfer limitations, hindering the process yield and the downstream of the produced bioproducts. Despite the difficulties, many successful processes have been reported on the production of a variety of bioproducts such as hydrolytic enzymes, mostly carbohydrases for bioethanol production, and to a lesser extent, aromas, biosurfactants, biopesticides, bioplastics, organic acids or phenolic compounds. Most of the reported research focuses on process development at a small scale; however, the main challenges to overcome in SSF are related to the upscaling and the development of consistent and continuous operation. In this work, the main advances in the production of valuable/innovative bioproducts are presented and discussed.