Periodic Reporting for period 1 - ENHANCEMENT (EXPLORING NEW HALO-AUTOTROPHIC PATHWAYS FOR THE DEVELOPMENT OF A NOVEL COST-EFFECTIVE DUAL METHANE AND CARBON DIOXIDE ELIMINATION TECHNOLOGY)
Reporting period: 2020-10-01 to 2022-09-30
Technologically, cell platforms fed with gases can be the most cost-effective option to eliminate them and to create chemicals necessary for human necessities and industrial development. CH4, CO2 and waste gases are almost free, require to be eliminated and are non-hazardous. There are hundreds of microorganisms out there able to use those gases and produce in exchange compounds that are very useful for our society. However, most current developed waste conversion processes are still not profitable due to the utilization of a small number of model microorganisms and the production of low-price compounds. Sectors that usually produce high valuable chemicals, such as the medical and pharmaceutical industry, still relay on the use of expensive feedstock, that in many cases competes with the food market.
ENHANCEMENT intends to shed light in a new industrial direction developing bio-factories that can produce interesting chemicals for the pharmaceutical and medical market with GHG and waste gases using novel bacteria. To this aim, we will look at currently overlooked microbes and strategies with the aim of abating the two most important GHGs, CO2 and CH4, as well as toxic waste gases. The target compounds will be molecules called ectoines. They have a retail value of €1200 kg-1 and possess outstanding chemical properties that make of them a target product in the pharmaceutical and medical market. Thus, in this project, novel bacteria that can abate GHG and waste gases will be implemented to produce compounds with high economic and social value.
1.1 We explored if species from the genus Halomonas were able to transform CH4 and CO2 into ectoines. Although for all the tested strains we obtained very small removals of methane, we observed complete removals of CO2. After biotechnological optimization, the results obtained showed that CO2 conversion coupled with discontinuous glucose addition increased the ectoine yields. This result can help in the development of sustainable ectoine platforms able to abate CO2 which had never been addressed to date (one published article).
1.2 We developed metagenomic and transcriptomic analyses with the aim of understanding better the bacterial population and metabolism dynamics involved in methane degradation under low and high methane cycles typical of natural methane treatment platforms. Overall, this study showed that there is an emergence and resilience of methanotrophic activity that can be applied to the operation of bioreactors subjected to the treatment of methane diffuse and dilute emissions. Moreover, it demonstrated that certain conditions and species support the bioconversion of methane into valuable products, such as bioplastics, without the requirement of external factors (one manuscript under review).
2. Simultaneous transformation of carbon dioxide and industrial waste into ectoines.
We explored the genetic potential for the microbial conversion of CO2 into ectoines, implementing a new methodology very interesting for the future development of cell factories. This method is called genomic mining and was used to identify microbes able to use CO2 as sole carbon source and that had the genes for ectoine and hydroxyectoine synthesis in their genomes. These analyses allowed us to find 31 species which can produce ectoine and hydroxyectoine and efficiently abate CO2 using simultaneously hydrogen, carbon monoxide, sulfur compounds, ammonium, or iron as the energy source. These preliminary findings represent the basis for the creation of novel microbial platforms that can promote the development of cost-effective and sustainable valorization chains of CO2 in different industrial scenarios (one published article and two international conferences).
3. Carbon dioxide conversion to fine chemicals using H2 as a green-energy source.
This research aimed to develop a technological process based on the use of unexplored microorganisms that grow in extreme conditions using CO2 as carbon and H2 as energy and can generate ectoine and hydroxyectoine for medicines´ production. To this aim, a total of 11 species containing the genes for ectoine and hydroxyectoine production were identified and selected for lab tests. After technological optimization and validation, we obtained three very productive strains able to produce ectoines while removing CO2. Overall, these results constituted the first proof of a novel valorization platform of CO2 and laid the foundation for a new economic niche aimed at CO2 recircularization into pharmaceuticals (one manuscript under review).
4. Dynamics and metabolisms implied in the microbial degradation of toxic gases.
During ENHANCEMENT, we also collaborated in different research lines based on the biological abatement of toxic gases such as toluene, limonene, hexane, pinene, trichloroethylene and siloxanes. In this collaboration, we developed metagenomic analyses of populations devoted to the degradation of toxic gases. These results helped in the understanding of the degradation of emerging environmental pollutants by unknown pathways and microorganisms and will be of key importance for the fate of biotechnologies treating volatile organic toxic compounds (6 published articles).