Transformation of Chitin and Waste Shrimp Shells into Acetic Acid and Pyrrole

Global shellfishery waste generation is from 6 to 8 million metric tons annually. Chitin, as a major component in crustacean shells, is the second most abundant biopolymer on Earth, having the potential to supplement the lignocellulosic biomass resource for renewable chemicals. Herein, we established direct transformation of chitin and raw shrimp shells into acetic acid (HAc) by a catalytic method using metal oxide and oxygen gas in basic water. The work showcased that chitin is a superior starting material to other major biomass resources for HAc production. A 38.1% yield of HAc was produced from chitin, which was more than a 2-fold increase compared with that from cellulose. Moreover, a 47.9% yield was directly obtained from crude shrimp shells. Another finding is that heterocyclic compound pyrrole was generated as the major nitrogen-containing (N-containing) product in the reaction system, which offers a potential chemical route for one-step pyrrole formation from a sustainable resource. The study opens new avenues to transform shellfishery waste into platform chemicals.