Converting environmental risks to benefits by using spent coffee grounds (SCG) as a valuable resource

Abstract

Coffee is perhaps one of the most vital ingredients in humans' daily life in modern world. However, this causes the production of million tons of relevant wastes, i.e., plastic cups, aluminum capsules, coffee chaff (silver skin), and spent coffee grounds (SCG), all thrown untreated into landfills. It is estimated that 1 kg of instant coffee generates around 2 kg of wet SCG; a relatively unique organic waste stream, with little to no contamination, separated directly in the source by the coffee shops. The produced waste has been under researchers' microscope as a useful feedstock for a number of promising applications. SCG is considered a valuable, nutrients rich source of bioactive compounds (e.g., phenolics, flavonoids, carotenoids, lipids, chlorogenic and protocatechuic acid, melanoidins, diterpenes, xanthines, vitamin precursors, etc.) and a useful resource material in other processes (e.g., soil improver and compost, heavy metals absorbent, biochar, biodiesel, pellets, cosmetics, food, and deodorization products). This paper aims to provide a holistic approach for the SCG waste management, highlighting a series of processes and applications in environmental solutions, food industry, and agricultural sector. Thus, the latest developments and approaches of SCG waste management are reviewed and discussed.

Activity of spent coffee ground cinnamates against wood-decaying fungi in vitro

“…The commercial viability spent coffee ground chemicals will strongly depend on availability of spent coffee grounds. The coffee industry generates large volumes of wet SCGs from the manufacture of instant coffee and caffeinated drinks (Pfluger 1975), and utilization of this resource is still a rather original and environmentally friendly approach of international and societal interest, avoiding the disposal of such residue in landfills (Stylianou et al 2018). Collecting the waste from private users may not be a feasible option, but collecting the SCGs from the coffee industry is a clear opportunity for its valorization.…”

Valorization of agro-industry residues in the building and environmental sector: A review

“…Spent coffee grounds, with their high calorific value close to 5.000 kcal kg −1 , can be turned into biodiesel (Kondamudi et al, 2008, Park et al, 2016 or exploited to produce fuel pellets and ethanol. Limited by their high lignin content, coffee grounds could also be a possible food source for ruminants, but the most suitable alternatives are linked to the transformation of cellulose and hemicellulose: the conversion of cellulose to glucose is the starting point for industrial-scale utilization (Mussatto et al, 2011, Stylianou et al, 2018. Future potential applications include incorporation to produce flakes, breads, biscuits, and aperitif snacks (Murthy et al, 2012).…”

The potential of spent coffee grounds hydrolysates fermented with Torulaspora delbrueckii and Pichia kluyveri for developing an alcoholic beverage: The yeasts growth and chemical compounds modulation by yeast extracts

“…Meanwhile, an increasing concern on the serious environmental pollution and resource wastes due to SCG largely disposing of at the landfill appeared ( Fernandes et al, 2017 ). However, SCG is rich in phenolics, carbohydrates, proteins, and lipids (Campos-Vega et al, 2015; Stylianou et al, 2018 ). Pre-treated SCG (e.g.…”