Reasons for studying bacteria
My path to science was quite clear-cut. I always loved it, especially physics and chemistry, so when I was 18 and had to choose what to do, I just followed what I liked most and was good at.
I got my first degree in chemical engineering from the University of Valladolid (Spain), and then I continued my studies at the National Chemical Engineering Institute (France). After I completed my studies, I decided to pursue a career in science and got my PhD. I also have some experience in the industry – I once worked as a bioinformatician for a private company.
My research now mainly focuses on environmental engineering, namely the purification of air and water. I approach these issues by modeling the metabolic reactions of various bacteria in different conditions.
In one of my projects, I studied the way Pseudomonas putida F1 bacteria contribute to the biodegradation of aromatic compounds of catechin (used in cosmetics), toluene, and benzole (both used in coating materials). I have also analyzed the way methanotrophic bacteria (or methanotrophs) contribute to the processing of methane, one of the main greenhouse gasses.
Apart from that, some of my research concerned the modeling of metabolic reactions in the cells of various organisms, from microbes to mammals. Each cell consists of many molecules, every one of which undergoes thousands of transformations – metabolic reactions. If you are a researcher planning to modify an organism’s genome, you need to know how the metabolic reactions in its cells will change when you add or delete a particular gene. We can predict these changes by modeling metabolic reactions.
For example, you can predict the amount of bacterial biomass that can be produced from a specific substrate (a carbon source where bacteria grow), as well as whether these bacteria will be pathogenic, and which genes are necessary for its functions. With modeling, you can solve different tasks. In collaboration with researchers from Chalmers University of Technology, Sweden, we tried to identify targets for antitumor medicine that will help to combat specific pathogenic bacteria.
At the University of Valladolid, we are focusing on developing new strains of methanotrophs, which oxidize methane and turn it into high added-value (HVP) products. Thus, Methylocystis II bacteria produce polyhydroxybutyrate – a biodegradable polymer that can be used in packaging, while Methylomicrobium alcaliphilum bacteria make ectoine – this compound is used in treatments against inflammation of skin and mucous membranes.
In the research project I currently lead at ITMO, I rely on all the knowledge and skills I acquired during my previous studies.
Bacteria as a power source
In St. Petersburg, I’m heading a project centered on bacteria that oxidize plastic derivatives. We want to see how such organisms can be applied in new ways. We are planning to build a microbial fuel cell that will produce electricity by oxidizing various organic compounds with the help of Paracoccus denitrificans bacteria.
We hope that our solution will have several applications: as a way to recycle non-degradable polyesters like PET, which see the most industrial use, and produce electricity to power electronic devices.
There are several reasons behind our choice of Paracoccus denitrificans. This bacterial species has several advantages in terms of its applications in our study. First, it is a denitrifier, which means it participates in the circulation of nitrogen in nature. These bacteria turn nitrates into nitrogen compounds that serve as nutrition for plants – which are then consumed by animals. Second, these bacteria can produce water-soluble electron carriers, which is a handy quality for a microbial power cell. Third, Paracoccus denitrificans can use different kinds of non-degradable polyester as its carbon and energy sources, producing instead polyhydroxybutyrate, a biodegradable type of plastic.
In order to make Paracoccus denitrificans capable of oxidizing the majority of monomers of non-degradable polyester, we created a strain of it that can break down the monomers’ shells. As compounds, namely polymer by-products on the anode, are oxidized, they generate electrons. These electrons are transferred to the electron acceptor on the cathode through an external electric circuit – and as a result, they produce an electric current. In this case, the strength of the current will depend on the amount of organic material in the microbial fuel cell.
I conduct my research as part of the ITMO Fellowship program in collaboration with Master’s students and researchers from ITMO’s Faculty of Ecotechnologies, including associate professors Nelli Molodkina and Olga Sergienko.
At the start of the project, we will be evaluating the resistance and power of the electricity produced by polyester-processing bacteria. Next, we are planning to modify the microorganism to increase its electricity production. If this stage is successful and the bacteria end up delivering enough electricity, then we will calculate the correlation between the efficiency of electricity production and the amount of processed organic substrate in the microbial fuel cell. Armed with this knowledge, we should be able to eventually use this tech to power various electronic devices, including smartphones.