The objective of this line is to recover the organic matter present in different wastewaters in the form of a high-value added product: polyhydroxyalkanoates (PHAs).
PHAs are naturally occurring polymers that many microorganisms are able to synthesize. Their physiological role is to serve as carbon and energy reserve. PHAs are known as bioplastics, because they present similar properties compared to conventional plastics, with the advantage of being biodegradable and synthesizable from renewable resources. The main drawback associated to the large scale production of PHA are the high costs associated to the production process, based on the use of pure cultures and expensive substrates.
As a solution, we propose a PHA production process based on the use of bacterial enrichments and wastewaters as substrate. On the one hand, the production costs will be significantly lowered, and on the other hand, the status of the wastewater will change from waste to resource.
The idea of using bacterial enrichments and waste as substrate arose from the fact that biological wastewater treatment processes are characterized by the exposure of microorganisms to transient conditions, where biomass is submitted to alternating periods of high and low substrate concentrations, and aerobic and anaerobic environments. Under these unbalanced conditions, it has been found that microorganisms respond by the production of PHAs.
The basis of the research is to make use of the ecological role of PHA as storage compound and apply a selective pressure that favors the growth of microorganisms with storage capability. Sequencing batch reactors (SBRs) are used for the establishment of microbial communities with high biopolymer producing capacity. In this research area, the group has focused its effort on the study of the feasibility of using different industrial wastewaters (fish cannery effluents, crude glycerol from biodiesel production plants...) as substrate for the establishment of PHA production processes. Moreover, the microbial consortia involved in the process is studied by using culture-independent molecular techniques such as denaturing gradient gel electrophoresis (DGGE) technique and fluorescence in situ hybridization (FISH).
Projects
· Integrative process development for biopolymer production through the valorisation of lipidic waste streams (ECOPOLYVER) Agencia Estatal de Investigación (Retos 2020. PID2020-112550RB-C21) (2021-2024)
· Biorrefinería centralizada para la valorización de efluentes del sector transformador de pescado en forma de bioplásticos (BIOCENPLAS) Ministerio de Agricultura Pesca y Alimentación (Desarrollo tecnológico, la innovación y el equilibrio de la cadena decomercialización en el sector pesquero y de la acuicultura 2021. 2021-PN070) (2021-2023)
· Development of a biotechnological process based on a single unit to obtain polyhydroxyalkanoates (PHA) from fatty wastes generated in industry (POLYGO1) NextGeneration EU, Strategic Projects Oriented to the Ecological and Digital Transition. (2022-2024)
Completed Projects
· Facing the treatment/recovery of saline wastewater to assure future water availability (TREASURE-TECHNOSALT)
Agencia Estatal de Investigación (Retos 2017. CTQ2017-83225-C2-1-R) (2018-2020)
· Sustainable system for the valorisation of fish canning wastewater for biopolymers production (FISHPOL)
Spanish Government.(CTQ2014-55021-R). (2015-2018)
Principal Researcher: A. Mosquera-Corral This project is focused on the valorisation of different liquid wastes by means of the utilization of mixed cultures to accumulate their organic carbon fraction present in these effluents in the form of polyhydroxyalkanoates (PHA) instead of the simple removal of these compounds in wastewater treatment processes. These accumulated compounds have different potential applications depending on their composition, such as bioplastics production, energy source or groundwater remediation.
The aim of this research work is to establish the optimum operational conditions to produce mixed cultures able to accumulate the PHA using liquid wastes like glycerol, from the biodiesel production process, characterized by the absence of ammonia content, and pre-acidified fish canning effluents containing ammonia. Furthermore these mixed cultures will be studied to achieve the operational conditions to reach the highest percentages of PHA accumulation with each substrate. Kinetic and stoichiometric parameters will be studied to obtain information regarding bioplastics productivity. Biomass enrichment and accumulation processes are highly dependent on the substrate composition. For this reason the effects of the use of different substrates and of the presence of potential inhibitors will be researched in the project. Experiments will be performed in lab-scale reactors and batch tests. In order to better understand the process the main bacteria populations contained in the obtained mixed culture will be identified by means of molecular techniques (FISH, DGGE, cloning). The composition of the produced storage compounds in the form of PHA such as polyhydroxybutyrate, valerate, etc. and also the occurrence of polyglucose accumulation will be studied to determine the possible applications of this stored bioplastics.
Furthermore obtained results will allow performing the calculation of the economic feasibility of different possible applications focused on the bioplastics production itself, the use of these accumulated compounds as energy resource to produce biogas and their use as organic carbon source for groundwater remediation to remove nitrogen oxides by denitrification.