Caracterización fenotípica del potencial biotecnológico de Listeria costaricensis para el aprovechamiento de xilosa

I In Costa Rica, the primary economic sector generates over 6.3 million tons of agro-industrial waste
annually, presenting environmental and economic challenges that require biotechnological solutions for
effective utilization. Xylose is one of the abundant components in this type of waste. Some microorganisms
can metabolize this sugar to produce various industrially relevant compounds such as biofuels, among
others. Previous research conducted at TEC, using in silico tools, found that the genome of the native
bacterium Listeria costaricensis contains a gene cluster associated with a complete metabolic pathway for
xylose degradation. Consequently, phenotypic biochemical tests revealed that this bacterium can ferment
D-xylose as a carbon source. Additionally, L. costaricensis is postulated to be non-pathogenic, as its
genome lacks some pathogenicity-related gene sequences, which is also consistent with previous basic
phenotypic tests indicating that L. costaricensis is unable to produce hemolysis in culture media or invade
HeLa epithelial cells under very specific conditions. Considering that L. costaricensis has only been
reported in Costa Rica, it could be well adapted to local environmental conditions and may be useful for
better utilizing the agro-industrial waste generated annually in Costa Rica. However, the phenotypic
characterization carried out in previous projects: 1) did not allow the identification of the products that this
bacterium could generate from xylose metabolism or their yields; 2) was not robust enough to demonstrate,
through various methodologies and models, that L. costaricensis is 100% non-pathogenic. This proposal
aims to continue previous research. To achieve this, the following is proposed: 1) conducting gene
expression assays to confirm that key xylose degradation genes identified in silico are correctly expressed;
2) performing in vitro xylose degradation assays to identify the resulting metabolites and evaluate their yield
and industrial applicability; 3) implementing new virulence assays for assessing the ability to adhere to the
eucariotic cell´s surface, in order to corroborate the non-pathogenicity of L. costaricensis, as this is crucial
for its safe use in industrial and environmental settings; 4) evaluating L. costaricensis's ability to produce
biofilms. It is worth mentioning that L. costaricensis was found in an industrial drain, suggesting it may form
biofilms. Confirming this ability is important, as it influences the design of operational parameters for a
potential bioprocess. The proposal is aligned with some of TEC's Strategic Knowledge Areas, like Habitat
and Industry. Additionally, it aligns with the Sustainable Development Goals number 7 and 12 and is
oriented towards solving specific problems identified by the “Estado de la Nación” report, like lack of
“Armony with the Environment” and “Warming and unsustainable patterns for the use of natural resources”.
Finally, it fits within the “Bioeconomy” strategic area of the MICITT's National Science, Technology, and
Development Plan for 2022-2027.

Caracterizar fenotípicamente la bacteria L. costaricensis
para la producción segura y eficiente de biocompuestos a partir de residuos
agroindustriales en Costa Rica.

Biotecnología Ambiental