Production of biopolymers

In the POLYBIO group, we employ bacteria to produce different materials that can be used to obtain bioplastics and other bio-based products:

PHA: Polyhydroxyalkanoates (PHA) are polyesters synthesized by bacteria as a form of energy and carbon storage, obtained from renewable and biodegradable feedstocks. Their capacity to completely degrade in nature make them a sustainable alternative to petrochemical-derived plastics, since they also present similar properties. Furthermore, PHA are the only bioplastics that are completely synthesized and degraded by bacteria, underpinning their role in a microbial circular economy model with the potential to inspire more sustainable production and recycling systems. However, one of the main challenges in PHA production is its elevated cost, due to the price of the feedstocks used, the bioprocess itself (which requires high-cell density cultures), and the downstream processes for polymer extraction and purification. In the POLYBIO group, we work on the optimization of PHA production processes, designing metabolic routes via synthetic and systems biology tools that allow the efficient synthesis of PHA, independently of environmental limitations. Additionally, we explore the use of residues as carbon source, not only to reduce costs, but also to make the production process more sustainable and aligned the circular economy principles.

Bacterial cellulose: Cellulose, the main component of wood, is widely used in textile, paper, and packaging industries thanks to its low cost and versatility. However, its production can lead to deforestation, biodiversity loss, and chemical pollution, contributing to climate change. Therefore, cellulose produced by bacteria (BC) represents a sustainable alternative that does not generate greenhouse gases or contaminated waste streams throughout its life cycle. BC is identical to plant cellulose in its composition, but presents significant differences regarding its structural conformation. BC stands out for its high purity, crystallinity, and porosity and its ordered fiber network. In the POLYBIO group, we work on the development of new biotechnological tools and strategies to domesticate BC-producing bacteria, namely Komagateibacter spp., to understand and improve BC biosynthesis.

Precursors for new polymers: Other than polymers that are naturally produced by microorganisms, biologically-sourced precursors for the chemical synthesis of polymers are of great interest. In the POLYBIO group, we seek to broaden the portfolio of available monomers for the development of new polymers with interesting properties. First, we can obtain R-3-hydroxyacids from the depolymerization of PHA, which are very interesting for the production of synthetic PHA and other high-value products thanks to their enantiomeric purity. Also, bacterial wax esters can serve as starting materials for the production of long-chain dicarboxylic acids (C16-C18), which can be used for the synthesis of chemically recyclable polymers with polyethylene-like properties, the most used plastic. With the ultimate goal of improving the biological production of these precursors, we study in detail the metabolism of model bacteria capable of producing PHA (Pseudomonas putida KT2440) and wax esters (Acinetobacter baylyi ADP1). By understanding the processes for the accumulation and utilization of these carbon storage compounds, we can modify bacterial metabolism to release R-3-hydroxyacids and long-chain dicarboxylic acids. Additionally, the development of sustainable downstream processes allows us to recover these compounds with high-purity in an environmentally-friendly way.

Relevant publications

Prieto, A., Escapa, I. F., Martínez, V., Dinjaski, N., Herencias, C., de la Peña, F., ... & Revelles, O. (2016). A holistic view of polyhydroxyalkanoate metabolism in Pseudomonas putida. Environmental Microbiology, 18(2), 341-357.

Manoli, M. T., Gargantilla-Becerra, Á., del Cerro Sánchez, C., Rivero-Buceta, V., Prieto, M. A., & Nogales, J. (2024). A model-driven approach to upcycling recalcitrant feedstocks in Pseudomonas putida by decoupling PHA production from nutrient limitation. Cell Reports, 43(4).

Hernández‐Arriaga, A. M., Del Cerro, C., Urbina, L., Eceiza, A., Corcuera, M. A., Retegi, A., & Auxiliadora Prieto, M. (2019). Genome sequence and characterization of the bcs clusters for the production of nanocellulose from the low pH resistant strain Komagataeibacter medellinensis ID 13488. Microbial Biotechnology, 12(4), 620-632.