Solid-state fermentation technology and innovation for the production of agricultural and animal feed bioproducts

It has now passed more than forty years since solid-state fermentation (SSF) research developments have gained importance for the scientific community. After so many years, numerous processes and equipment for SSF were studied and designed focusing on the production of different commercially relevant bioproducts such as enzymes, fermented food, such as Chinese daqu and koji, organic acids, pigments, phenolic compounds, aromas, biosorbents and so many others. However, no review paper has been focused yet specifically on agricultural and animal feed bioproducts obtained through SSF techniques. This review comprises the description of agricultural sub-products that have been employed in most important developed processes concerning the production of animal feed products and agricultural products such as spores, probiotics, biofungicides, bioinsecticides and other biopesticides, biofertilizers and plant growth hormones. Major designed SSF bioreactors are also described and the most important related cases of successful employment of the technique are reported. Finally, a summary of patents and innovations regarding SSF products and processes in this area is presented, showing that the main involved countries are China, South Korea, India and the USA. It is clear that the interest in this theme is increasing and that scientific and technological developments are still needed.