Kombucha SCOBY Waste as a Catalyst Support

Abstract

It is established that food waste can be repurposed to extend its lifecycle and decrease its carbon footprint. In this work, SCOBY (symbiotic culture of bacteria and yeast) waste from kombucha tea production has been repurposed as a catalyst support. Copper nanoparticles (Cu NPs) have been embedded in a piece of treated SCOBY via an in-situ method which enabled the catalyst, inCu/t-SCOBY, to be easily recycled. In addition, inCu/t-SCOBY catalyzed the full reduction of 4-nitrophenol in an excess of sodium borohydride (NaBH₄ ) within 20 minutes. After 6 additional catalytic cycles, the catalyst maintained up to 50% of its performance in the first cycle. Characterization of the catalyst has also been done to understand the mechanism of action and interactions occurring between t-SCOBY and Cu NPs. The results of this work clearly present a proof-of-concept in utilizing porous wastes materials such as SCOBY as catalyst supports, allowing metallic NPs to be efficacious and practical heterogenous catalysts.

Keywords: Waste Valorisation; bacterial cellulose; catalyst support; catalytic reduction reaction; copper nanoparticles; food waste; kombucha SCOBY.