A Review of the Feasibility of Producing Polylactic Acid (PLA) Polymers Using Spent Coffee Ground

Abstract

Coffee is one of the most popular beverages in the world. Annual coffee consumption continues to increase, but at the same time, it generates a large amount of spent coffee grounds from the brewing process that give rise to environmental problems. An appropriate solution to manage these spent coffee grounds (SCGs) becomes crucial. Our project aims at discussing the feasibility of utilizing SCGs to synthesize polylactic acid (PLA) as a recycling application for SCGs. Producing PLA from SCGs offers the opportunity to contribute to the circular economy and sustainability due to the significant volume of coffee consumption. This approach reduces waste, provides environmental benefits, and promotes the use of renewable resources. Through repurposing SCGs into PLA, we can close the loop, minimize environmental impact, and create a more sustainable alternative to fossil-fuel-based plastics. This paper first discusses the properties and potential recycling applications of spent coffee grounds. The production of PLA from lactic acid and the potential processes for converting SCGs to lactic acid are then briefly discussed. From our review, it is feasible to utilize SCGs as the primary source for lactic acid production via bacteria fermentation and, further, to produce PLA via ring-opening polymerization. Possible ways to improve the yield and a corresponding cost analysis are also discussed.