Biofuels Production from Orange Juice Industrial Waste within a Circular Economy Vision

Abstract

The orange juice industry is a dynamic food industrial sector that produces large amounts of waste given that more than half of the processed fruit ends up as waste. In order to reduce its environmental impact, it is usually used as animal feedstuff, either as it is (fresh orange waste) or dehydrated (pressed orange waste) or as silage. In an effort to meet the EU circularity goals, these three possible raw materials were assessed as feedstocks for biogas and/or bioethanol production. Fresh orange waste could provide the highest energy yield via anaerobic digestion (32 m3 biogas/tn orange processed), while the pressed orange waste and silage resulted in the production of 20 and 11 m3 biogas/tn orange processed respectively. The coupling of enzymatic hydrolysis (with 50μL CellicCTec2/g cellulose) and ethanolic fermentation (with 2% w/w Saccharomyces Cerevisiae) with biogas production for fresh orange waste resulted in the production of 336 MJ/tn orange processed. Conclusively, orange juice industry could meet the EU sustainability goals via valorisation of its waste.

Keywords: bioethanol, biogas, biorefinery, fresh orange waste, pressed orange waste, silage