Solid-State Fermentation from Organic Wastes: A New Generation of Bioproducts

Abstract

Solid-state fermentation (SSF) is part of the pathway to consolidate waste as a relevant alternative for the valorization of organic waste. The objective of SSF is to produce one or several bioproducts of added value from solid substrates. Solid-state fermentation can use a wide variety of organic waste as substrates thus, it is an excellent candidate in the framework of the circular bioeconomy to change the status of waste from feedstock. The development of SSF was boosted in the previous decade by scientific efforts devoted to the production of hydrolytic enzymes. Nowadays, SSF has expanded to other valuable products: biosurfactants, biopesticides, aromas, pigments, and bio-flocculants, among others. This review explores the conditions to obtain the main emerging SSF products and highlight and discuss the challenges related to the scale-up of these processes and the bioproducts downstream, which hamper their further commercialization.

Carbon and nitrogen optimization in solid-state fermentation for sustainable sophorolipid production using industrial waste

“…However, compared with the results obtained by Rodríguez et al (2020), who reported a crude SL yield of 0.2 g g -1 DM i using WOC and molasses as feedstock at 22 and 100 L, respectively, the SL yields achieved in this study are lower. Nevertheless, it should be considered that the present experiment was set up at a flask scale, and in this sense, the results could be improved in a scale-up process applying aeration and agitation (Raghavarao et al, 2003;Oiza et al, 2022).…”

“…SSF is developed in the absence or limitation of free water (Pandey, 2003) and allows the sustainable conversion of organic insoluble solid waste into high-value-added products (Jiménez-Peñalver et al, 2016;Hu et al, 2021). The main challenges of SSF revolve around sample heterogenicity and mass and heat transfer, which are intrinsic characteristics of solid matrices (Kumar et al, 2021;Oiza et al, 2022). Temperature and composition gradients are often reported when scaling up SSF systems, pointing to the co-existence of different metabolic states for cells growing in the solid matrix.…”

Solid-State Fermentation: Applications and Future Perspectives for Biostimulant and Biopesticides Production

“…Furthermore, SSF can be a way of recycling such wastes, as they are a source of pollution that must be disposed of. Another factor that could reduce costs is the fact that it does not require to use energy to heat the process [ 66 , 214 , 215 , 216 ]. As with other techniques, SSF has limitations.…”

“…This allows SSF to be a more cost-effective and lower solvents usage process than SmSF. The SSF constraints, the numerous approaches being used to solve them, and the potential future directions for further developing this biotechnology to increase its competitiveness in the worldwide market were all covered in detail by Oiza et al [ 216 ].…”

Solid-state fermentation: a review of its opportunities and challenges in the framework of circular bioeconomy

“…In practical terms, SSF takes place in a bioreactor, typically aerobic, which is filled with the solid substrate and inoculated with the strain of interest to produce the desired bioproduct [6]. Once produced, this bioproduct must be recovered, although in some cases the final fermented solid can be used as end product, without a defined downstream process [7].…”