Page 231 - IJB-9-4

International Journal of Bioprinting

RESEARCH ARTICLE
Valorization of agar production residue as a filler

in soy protein hydrogels for 3D printing

Jone Uranga , Teresa Carranza , Miriam Peñalba , Koro de la Caba *,
1
1
1,2
1
Pedro Guerrero 1,2,3 *
1 BIOMAT Research Group, University of the Basque Country (UPV/EHU), Escuela de Ingeniería de
Gipuzkoa, Plaza de Europa 1, 20018 Donostia-San Sebastián, Spain
2 BCMaterials, Basque Center for Materials, Applications and Nanostructures, UPV/EHU Science
Park, 48940, Leioa, Spain
3
Proteinmat Materials SL, Avenida de Tolosa 72, 20018 Donostia-San Sebastián, Spain
(This article belongs to the Special Issue: Novel hydrogels/bioinks formulations prepared from naturally derived
components for 3D Bioprinting)

Abstract

Cellulose-containing residue from agar production was incorporated as a filler
into soy protein-based hydrogels and revalorized without further purification.
Rheological assessment of these hydrogels was carried out in order to confirm their
shear-thinning behavior and their suitability for 3D printing. It was observed that
all hydrogels behaved as weak gels, which are suitable for 3D printing and have
good printability and shape fidelity. The addition of cellulose did not cause chemical
crosslinking but physical interactions, which led to morphological changes, thereby
promoting hardness and shape recovery of the 3D-printed products. The hydrogel
with the highest residue content (8 wt %) showed the highest value (78%) in shape
*Corresponding authors: recovery. Furthermore, the physicochemical characterization of these 3D-printed
Pedro Guerrero products revealed that although they have high swelling capacity, they preserve their
(pedromanuel.guerrero@ehu.es)
Koro de la Caba integrity in wet conditions. These results suggested the potential of the 3D-printed
(koro.delacaba@ehu.es) products developed using residues without further purification to promote circular
economy, increasing the efficiency in resources utilization.
Citation: Uranga J, Carranza T,
Peñalba M, et al., 2023, Valorization
of agar production residue as a
filler in soy protein hydrogels for Keywords: Hydrogels; Proteins; Cellulose; Rheology; 3D printing
3D printing. Int J Bioprint, 9(4): 731.
https://doi.org/10.18063/ijb.731
Received: February 03, 2023
Accepted: March 05, 2023 1. Introduction
Published Online: April 10, 2023
Population growth, diversification of individual consumption, urban concentration,
Copyright: © 2023 Author(s). increasing number of industries, and lack of strategies for treating waste all contribute
This is an Open Access article
distributed under the terms of the to many problems associated with the environment and human health. In line with
Creative Commons Attribution circular economy and zero-waste discharge policies, one of the emerging tendencies
License, permitting distribution, in recent years is to prepare novel and environmentally-friendly materials such as
and reproduction in any medium, [1-3]
provided the original work is residues from industry . In this context, the exploitation of red algae, especially
properly cited. Gelidium sesquipedale, which is widely available around the world, for the production
of agar products is important for several industries, ranging from cosmetics to the food
Publisher’s Note: Whioce
[4]
Publishing remains neutral with industry . The industrial processing of red algae generates a large quantity of solid
regard to jurisdictional claims in fibrous wastes, which constitute a source of serious environmental problems. The agar
published maps and institutional extraction process produces a substantial amount of residue (15%–40% of the initial
affiliations.

Volume 9 Issue 4 (2023) 223 https://doi.org/10.18063/ijb.731