Spent coffee grounds: Present and future of environmentally friendly applications on industries-A review

Solid waste spent coffee grounds (SCGs) are generated in the process of producing coffee products. SCGs currently exist in the main treatment methods of incineration and sanitary landfill, causing the waste of resources and environmental pollution. It is urgent to establish and improve the large-scale biological joint transformation process system for comprehensive utilization of SCGs. This paper firstly summarizes the processing technology of SCGs including its main compositions and extraction methods. Furthermore, an overview of SCGs utilization is presented in following aspects consists of agronomy and composting, fermentation, bioremediation, bioenergy, carbon points, food and cosmetics. Finally, it provides an outlook on its future utilization and research directions. SCGs are rich in beneficial components, being considered as high value-added biomass resources with great potential for sustainable development. After appropriate disposal and resource transformation, SCGs have been widely applied in fields of food, pharmaceutical, cosmetic, energy and materials sectors. The technologies currently available make the full utilization of SCGs possible, taking into account safety and social acceptance. Utilizing the power of innovation and biotechnology to upcycle SCGs is a way to turn food waste into treasure and achieve sustainable social green development. [Display omitted] •Overview of the main components and related bioactivities of SCGs.•Extraction technology progress of bioactive substances from SCGs is reviewed.•Applications of SCGs are in the fields of food, agronomy and materials.•Future perspective for SCGs comprehensive utilization and recovery is illustrated.