Apelsinskalsavfall från juiceproduktion undersöktes som råmaterial för att producera biopolymerer som cellulosa och kitin/Kitson. Genom kemisk och biologisk behandling med Rhizopus delemar erhölls biopolymerer med förbättrad termisk stabilitet. Resultaten visar att apelsinskal kan återanvändas som ett hållbart material inom bioekonomin.

Orange peel is an abundant waste of the citrus industry, with approximately 50% of the fruit being discarded as waste after juice extraction. This waste contains nutrients, that could be used as substrate for fungal cultivation, and lignocellulosic biopolymers such as cellulose, hemicellulose and pectin. Therefore, this research investigates the possibility of utilizing orange peel waste to produce valuable biopolymers, namely cellulose and chitin/chitosan, via chemical extraction and biological conversion using the filamentous fungus Rhizopus delemer. The orange peel was subjected to hydrolysis, and the nutrient-rich liquid was used for fungal growth, while the solid residues were processed for cellulose via alkaline treatment and bleaching. Fungal cultivation was conducted in 250 mL Erlenmeyer flasks and a 26 L bubble column bioreactor around 7kg of wet orange peel used gives around 0.55kg of cellulose and 0.80kg of biomass. FTIR, TGA, and elemental analysis were used to study the resulting biopolymers. The results showed improved thermal stability and high cellulose content after purification of orange peel solid residues, and results for chitin/chitosan in the biomass. This study indicates that orange peel waste can be a valuable and sustainable raw material supporting bioeconomy