Formulation and characterization of gelatin-based hydrogels for the encapsulation of Kluyveromyces lactis: Applications in packed-bed reactors for lactic acid production

The versatile applications of lactic acid in different industries such as food, polymers, materials and the increasing demand for 3D printing (as thermoplastic) has promoted significant attention to the research about production improvement. This metabolite has been mainly produced by a microbiological pathway [1] with several disadvantages including low cell survival and variable yields. To overcome these issues, here we propose to encapsulate the yeast Kluyveromyces lactis on chemically crosslinked gelatin hydrogels as a means to improve the production of lactic acid. The developed approach can be eventually extended to other metabolites of industrial and research interest. The synthesized hydrogels were characterized in terms of morphological, physical-chemical, mechanical, thermal, and rheological properties. This comprehensive characterization allowed us to identify key parameters to facilitate encapsulation, maximize cell survival, and consequently the amount of produced lactic acid. According to the results, it was found that the hydrogels with high concentration of gelatin (7.5% w/v) and high concentration of glutaraldehyde (3% and 5% w/w) were suitable for cell encapsulation as they exhibit pore sizes, rigidities and sufficient stability for bioreactor operation for several days. Finally, high live/dead ratio (all above 90%) was determined for the hydrogels before and after 72 hours bioreactor operation. Cell proliferation assay confirmed that 5.0% GTA hydrogel induces a higher dead cell level. A proof-of-concept experiment in a low volume airlift bioreactor (termed milibioreactor) showed promising results with final lactic acid concentrations between 15 and 22 mg/mL after completing the operation.

• Autores: Patarroyo Arguello, Jorge Luis
• Tipo de recurso: Trabajo de grado de pregrado
• Fecha de publicación: 2019
• Institución: Universidad de los Andes
• Repositorio: Séneca: repositorio Uniandes
• Idioma: eng
• OAI Identifier: oai:repositorio.uniandes.edu.co:1992/44920
• Acceso en línea: http://hdl.handle.net/1992/44920
• Palabra clave: Acido láctico; Kluyveromyces lactis; Hidrogeles; Levaduras; Reología; Ingeniería
• Rights: openAccess
• License: http://creativecommons.org/licenses/by-nc-nd/4.0/