Re ECF Project: 2014-31

Project Title: Valorization of the Exoskeletons of Crustaceans in Seafood Waste into Chemicals and Fuels

Applicant: Professor Istvan T HORVATH, City University of Hong Kong

Total Approved Grant: $1,373,720 (ECF & WWGF: 50/50)

Duration: 1/1/2015 to 31/3/2017

Project Status/Remarks: Completed

This project aims to develop a sustainable process for the conservation of the hydrogen, carbon, oxygen, and even nitrogen atoms of the exoskeletons of crustaceans (lobsters, shrimps, crabs, etc.) in seafood wastes. The proposed valorization of the exoskeletons will be achieved by converting some of the key inorganic and organic components, including calcium carbonate and chitin, to carbon-based chemicals and fertilizers.

Summary of the Findings/Outcomes:

The conversion of the exoskeletons of crustaceans to chemicals is an attractive approach to valorize seafood wastes in Hong Kong. After multistep pre-treatment, the processed seafood wastes can be converted to acetic acid, levulinic acid, formic acid, 2-furaldehyde, and ammonium salts using sulphuric acid from moderate to good yields. The neutralization of the reaction mixture with aqueous sodium or ammonium hydroxide allows the use of the Shvo’s catalyst for the transfer hydrogenation of levulinic acid with formic acid to produce gamma-valerolactone. The salt out effects of the ammonium and sodium sulphates could result in the formation of liquid-liquid biphasic systems. While the organic phase contains most of the levulinic acid and gamma-valerolactone, the inorganic salts remain in the aqueous phase. In order to facilitate the transfer-hydrogenation of levulinic acid with formic acid, the Shvo’s catalyst was immobilized onto a magnetic silica support to provide easy separation even in the presence of slurry reaction mixtures containing solid residues. Toxicology studies using juvenile marine medaka fish showed that 2-furaldehyde was significantly more toxic than 5-(hydroxymethyl)furfural, levulinic acid, formic acid, and gamma-valerolactone. Mechanistic studies have shown that deamination of glucosamine was the rate-determinate step in the conversion of chitin to levulinic acid. The research results were presented in international conferences and published in scientific journals.