Extraction of cellobiose from spent coffee grounds and prebiotic potential of commercial cellobiose

Huang, M. (2025) Extraction of cellobiose from spent coffee grounds and prebiotic potential of commercial cellobiose. PhD thesis, University of Reading. doi: 10.48683/1926.00127373

Abstract/Summary

Valorising abundant agro-industrial waste like spent coffee grounds (SCG) is a key goal of the circular bioeconomy, but its potential for producing high-value functional food ingredients remains underexplored compared to its use for biofuels. This thesis developed a novel pathway to produce cellobiose from SCG and assessed the prebiotic potential of commercial cellobiose. A laboratory-scale process was first established using an optimised alkaline pretreatment (4 M NaOH, 40 °C, 24 h), which increased glucan content from 11.6% to 18.9%. Targeted enzymatic hydrolysis with a low-β-glucosidase, endoglucanase-rich cocktail enabled cellobiose accumulation with minimal glucose by-product. The prebiotic potential of cellobiose was evaluated through in vitro batch fermentation with human faecal inocula and a randomised, double-blind, placebo-controlled human trial (n = 37). Cellobiose was well tolerated up to 10 g/day. Although no statistically significant changes in microbiota composition were observed, correlation analysis revealed that cellobiose drives tight, community-level shifts among interconnected butyrate-producing bacteria. This work establishes a proof-of-concept for producing cellobiose from SCG and provides the first comprehensive analysis of its effects on the human gut microbiota. The findings establish a strong foundation for developing cellobiose as a novel prebiotic from a sustainable waste stream.

Item Type	Thesis (PhD)
URI	https://centaur.reading.ac.uk/id/eprint/127373
Identification Number/DOI	10.48683/1926.00127373
Divisions	Life Sciences > School of Chemistry, Food and Pharmacy > Department of Food and Nutritional Sciences
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