RT journal article
T1 Strategic biorefinery approach for closing the loop in the sugar industry: Valorisation of exhausted pulp into PHB via integrated bioconversion and kinetic modelling
A1 Guzmán Gaona, Angela
A1 Gómez Quiroga, Xiomara
A1 Romero Vargas, Agustín
A1 Álvarez Gallego, Carlos José
A1 Blandino Garrido, Ana María
A1 Romero García, Luis Isidoro
A2 Ingeniería Química y Tecnología de Alimentos
K1 Exhausted sugar beet pulp (ESBP)
K1 Dark fermentation (DF)
K1 Polyhydroxybutyrate (PHB)
K1 Cupriavidus necator
K1 Kinetic modelling
K1 C/N ratio
K1 Volatile fatty acids (VFAs)
AB The transition towards a circular bioeconomy requires the conversion of agro-industrial residues into valuable bioproducts. This study investigates an integrated approach to producing polyhydroxybutyrate (PHB) using exhausted sugar beet pulp (ESBP) as a sustainable source of material. Initially, the ESBP was processed via thermophilic dark fermentation to yield a volatile fatty acid (VFA) rich effluent (15.1 g/L) dominated by acetic and butyric acids. Subsequently, the effect of the C/N ratio (44, 35 and 20) on PHB synthesis by Cupriavidus necator was evaluated. The experimental results showed that the raw effluent (C/N 44) triggered the highest specific polymer accumulation (77.5% of cell dry weight). To gain insight into the bioconversion dynamics, an unlumped kinetic model was developed and validated (R² > 0.95), effectively decoupling residual biomass growth from PHB accumulation. The model successfully identified a critical harvest time by incorporating an intracellular degradation term, thereby preventing product loss under substrate-limiting conditions. For the C/N ratios of 44 and 35, the maximum volumetric productivity was in the range of 0.063–0.066 g·L⁻¹ ·h⁻¹ and the optimum harvesting time was in the range of 48.2–49.1 h, during which the PHB accumulation would be 65.3–65.5%. These findings suggest that non-supplemented fermentation of sugar beet pulp could be a cost-effective and efficient process for producing sustainable bioplastics.
SN 2213-2929
YR 2026
FD 2026-08
LK http://hdl.handle.net/10498/39654
UL http://hdl.handle.net/10498/39654
LA eng
NO Grant PID2023-146737OB-I00 funded by MICIU/AEI/ 10.13039/501100011033 and by “ERDF/EU” and by the BEET2BIO project (FEDER-UCA-2024-A2–07), funded by the Andalusia ERDF Operational Program 2021–2027.
DS Repositorio Institucional de la Universidad de Cádiz
RD 21-sep-2026