Collectively, these research papers and reviews are focused on green, eco-friendly, and easily scalable processes, with a view to facilitate a sustainable and circular economy. Some research papers deal with new extraction procedures to obtain cellulose or lignin, the recycling of biomass into high-value-added materials, as well as important developments in research and technology, which have also been reported in the study of some proteins and different polysaccharides such as chitosan, tea polysaccharides, and hyaluronan, how to reduce sugars in foods to obtain silver nanoparticles, and the valorization of some byproducts such as Nopal Mucilage and milk whey hydrolysates. This Reprint is addressed to experts interested in the large-scale development/valorization of different natural resources into high-value materials, engineers, researchers, and PhD students who may be performing their studies using the modern techniques used in the published papers.