Master's Thesis
Strategies to produce Single-cell protein from hydrolysates of industrial residues of Gelidium corneum using GRAS microorganisms in one or two bioreactors in series
— 2025
Key information
Authors:
Supervisors:
Published in
03/25/2025
Abstract
As the global population continues to rise, the demand for alternative food/feed sources in particular protein sources, has become increasingly urgent. This study explores the use of hydrolysates of industrial residues of the red seaweed Gelidium corneum, as a low-cost, sugar-rich feedstock for fermentation aiming at single cell protein (SCP) production. Residues after agar extraction used in this work were composed of 27.3 ± 3.0 g/100g DW carbohydrates and 36.0 ± 1.2 g/100g DW protein. Enzymatic hydrolysis with cellulases yielded 91.6% of the total releasable glucose. Glucose-rich hydrolysates were used as carbon-source to microbial cultures aiming at SCP production. Bench-scale bioreactor assays were conducted using either a Lactobacillus consortium (4LAB) or a mixed culture of Saccharomyces cerevisiae and 4LAB. Slightly higher levels of lactic acid (LA) (110 g/L) were produced compared to 4LAB fermentation (101 g/L). To enhance protein content, an innovative sequential fermentation was developed using the 4LAB consortium in the first bioreactor and Corynebacterium glutamicum in the second bioreactor, feeding on the LA produced by 4LAB. Although C. glutamicum exhibited poor tolerance to high LA concentrations, it produced a fermented product containing SCP with 15.7 g protein/ 100 g DW. All fermented products exhibited increased protein bioaccessibility when compared to the raw Gelidium residues and increased antioxidant activity was exhibited by the 4LAB fermented product. These findings highlight the potential of using fermentation for the valorisation of a marine waste stream to produce a product with enhanced nutritional properties.
Publication details
Authors in the community:
Diogo Jacinto Marques
ist189742
Supervisors of this institution:
Marília Clemente Velez Mateus
ist12931
Fields of Science and Technology (FOS)
industrial-biotechnology - Industrial Biotechnology
Publication language (ISO code)
eng - English
Rights type:
Embargoed access
Date available:
12/27/2025
Institution name
Instituto Superior Técnico