Nanocellulose and Bioethanol Production from Orange Waste using Isolated Microorganisms

Abstract

Citrus processing waste from oranges (CPWO) was explored for the production of nanocellulose and bioethanol. After the isolation of 20 microorganisms from CPWO, their fermentation abilities were screened and two microorganisms identified as Candida parapsilosis strains IFM 48375 and NRRL Y-12969 (ATCC 22019) were selected for a further fermentation. The CPWO was steam distilled for the isolation of essential oil (1.5% g g-1 of dry CPWO) and converted into a mixture of fermentable sugars (40% g g-1 of dry CPWO) using acid or enzymes hydrolyses. Hydrolyzates were fermented with three different yeast strains, the two Candida sp. and Saccharomyces cerevisiae. Candida parapsilosis strain IFM 48375 accomplished excellent results in ethanol production (21% g g-1 of dry CPWO) from CPWO, higher when compared to other strains. Nanocellulose (2.5% g g-1 dry CPWO) and nanofibers (0.5% g g-1 dry CPWO) were isolated from solid residues obtained from enzymatically treated and fermented CPWO. To the best of our knowledge, this work reports for the first time the nanocellulose production from CPWO.