A biorefinery for conversion of citrus peel waste into essential oils, pectin, fertilizer and succinic acid via different fermentation strategies. (15th July 2020)

• Record Type: Journal Article
• Authors: Patsalou, Maria; Chrysargyris, Antonios; Tzortzakis, Nikolaos; Koutinas, Michalis
• Is Part Of: Waste management. Volume 113(2020)
• Page Start: 469
• Page End: 477
• Publication Date: 2020-07-15
• Subjects: Citrus peel waste -- Biorefinery -- Succinic acid -- A. succinogenes -- Fertilizer; ADF acid detergent fiber -- ADL acid detergent lignin -- AFP air-filled porosity -- AWHC available water holding capacity -- BD bulk density -- BR biorefinery residues -- CPW citrus peel waste -- CSL corn steep liquor -- drm dry raw material -- FW food waste -- GC-MS gas chromatography-mass spectrometry -- HPLC high pressure liquid chromatography -- MDA malonialdehyde -- NDF neutral detergent fiber -- sa succinic acid -- SR solid residue -- SSF simultaneous saccharification and fermentation -- TPS total pore space -- tsc total sugars consumed -- TSB tryptic soy broth; Hazardous wastes -- Periodicals; Refuse and refuse disposal -- Periodicals; 363.728
• DOI: 10.1016/j.wasman.2020.06.020
• Languages: English
• ISSNs: 0956-053X

Abstract

Graphical abstract: Highlights: A biorefinery process isolated essential oils (0.43%) and pectin (30.53%) from CPW. D-limonene comprised 97% of essential oil's composition among 17 compounds detected. Combined use of CSL and vitamins in CPW hydrolyzates enhanced succinate production. Fed-batch fermentation improved succinate production from CPW hydrolyzates by 27% Biorefinery residues were used as fertilizer imposing stress on plant growth. Abstract: A process for the valorization of citrus peel waste (CPW) has been developed aiming to produce succinic acid and a series of added-value products through the biorefinery platform. CPW was subject to physicochemical and biological treatment to isolate essential oils (0.43%) and pectin (30.53%) as extractable products, pretreating the material for subsequent production of succinic acid that enabled application of remaining biorefinery residues (BR) as fertilizer substitute. Cellulose, hemicellulose and lignin contents of CPW accounted for 22.45%, 8.05% and 0.66% respectively, while acid hydrolysis reduced hemicellulose by 3.42% in BR. Moreover, essential oils extracted from CPW included 17 compounds, among which D-limonene reached 96.7%. The hydrolyzate generated was fermented for succinic acid production using Actinobacillus succinogenes . Different batch experiments demonstrated that the combined use of corn steep liquor (CSL) and vitamins in a lab-scale bioreactor resulted in product concentration and yield that reached 18.5 g L −1 and 0.62 g g −1 respectively. Although simultaneous saccharification and fermentation (SSF) could not enhance succinic acid production, a fed-batch fermentation strategy increased succinic acid concentration and yield generating 22.4 g L −1 and 0.73 g g −1 respectively, while the mass of the platform chemical formed was enhanced by 27% as compared to the batch process. BR was explored as fertilizer substitute aiming to close the loop in the management of CPW towards development of a zero-waste process demonstrating that although the material imposed stress on plant growth, the content of potassium, phosphorus and nitrogen in the mixture increased.