Sustainable production of single-cell oil and protein from wastepaper hydrolysate: identification and optimization of a Rhodotorula mucilaginosa strain as a promising yeast

• Published in: FEMS yeast research Vol. 23
• Main Authors: Campos-Valdez, Amador, Kirchmayr, Manuel R, Barrera-Martínez, Iliana, Casas-Godoy, Leticia
• Format: Journal Article
• Language: English
• Published: Hoboken Oxford University Press 04-01-2023
• Subjects: Carbon sources; Cell culture; Fatty acids; Hydrolysates; Lipids; Liquid culture; Oils & fats; Proteins; Rhodotorula mucilaginosa; Waste management; Yeast; fatty acid; single-cell protein; single-cell oil; oleic acid; wastepaper
• ISSN: 1567-1364; 1567-1356; 1567-1364
• DOI: 10.1093/femsyr/foad044

Abstract
This study investigated the potential of wastepaper hydrolysate as a sustainable and low-cost carbon source for single-cell oil and protein production, attending to the growing need for alternative feedstocks and waste management strategies. Wastepaper, characterized by its high carbohydrate content, was subjected to enzymatic and chemo-enzymatic treatments for carbohydrate release. The chemo-enzymatic treatment performed better, yielding 65.3 g l−1 of fermentable sugars. A total of 62 yeast strains were screened for single-cell oil accumulation, identifying Rhodotorula mucilaginosa M1K4 as the most advantageous oleaginous yeast. M1K4 lipid production was optimized in liquid culture, and its fatty acid profile was analyzed, showing a high content of industrially valuable fatty acids, particularly palmitic (28%) and oleic (51%). Batch-culture of M1K4 in a 3-l reactor demonstrated the strain’s ability to utilize wastepaper hydrolysate as a carbon source, with dry cell weight, total lipid and protein production of 17.7 g l−1, 4.5 g l−1, and 2.1 g l−1, respectively. Wastepaper as a substrate provides a sustainable solution for waste management and bioproduction. This research highlights the potential of R. mucilaginosa for lipid and protein production from wastepaper hydrolysate.
This study showcases the innovative use of waste paper as a sustainable source for producing valuable oils through a specific yeast strain, offering a novel solution to both waste management and food production challenges.