Hydrogen from the Algae Factory
What if the cars of the future were to run on climate-neutral fuels such as hydrogen, which could even be generated with the help of algae from the roofs of private houses? Or what if home-bred bacteria were to contribute to heating our homes? For the time being, the private use of self-generated energy from living microorganisms remains a vision of the future.
As matters stand, many technologies – such as hydrogen production from algae or bacteria – have not yet made it past the test phase. If they ever reach market maturity, the mini power plants could help in the future to replace fossil fuels. Certain microalgae and bacteria, for example, produce hydrogen as part of their natural metabolism (you can see how it works here).
From a technical standpoint, many things are already possible today, for instance, the production of biogas, biodiesel and bioethanol, as well as hydrogen from algae or bacteria. [1] The major advantage of microorganisms over corn, rapeseed or other plants is that they do not grow in fields that could otherwise be used for food production, but are bred in closed reactors – for example in the desert, on roofs or even in cellars with artificial lighting.
Algae as climate-neutral suppliers of hydrogen
Algae, in particular, are considered to be promising future energy sources. However, researchers and developers still need to find the answers to many questions before algae can be used efficiently. For example, huge water tanks are currently still required to produce enough algae for practical hydrogen production. Scientists at the Mülheim-based Max Planck Institute for Chemical Energy Conversion (MPI CEC) and Max Planck Institute for Coal Research (MPI KoFo), as well as at Ruhr University Bochum’s Photobiotechnology Research Group have succeeded in modifying microalgae in such a way that they produce five times more hydrogen. Therefore, in the future, these modified algae could produce hydrogen on much smaller surface areas – and make redundant the rare and expensive precious metals that are currently required for hydrogen production from water. [2]
Highly efficient miniature hydrogen power plants
The researchers’ approach is to use the genetically modified protein ferredoxin to get the so-called hydrogenases in the algae cells to produce more hydrogen. Hydrogenases are the enzymes in living organisms that produce hydrogen (more about hydrogenases and enzymes).
The scientists in Bochum are pushing ahead with their basic research into special hydrogenases which, according to the Photobiotechnology Research Group, could play a key role in the green, hydrogen-based energy industry of the future. [3] The studies aim to help modify – and even reproduce a simplified form of – these hydrogenases so that they can be used specifically for hydrogen production. [4]
At the Karlsruhe Institute of Technology (KIT), researchers are developing sustainable methods of production for the extraction of hydrogen from microalgae. Scientists at the KIT’s Institute of Process Engineering in Life Sciences (BLT), for example, have created a photobioreactor that enables more energy-efficient algae cultivation. What makes this reactor so special is that its surface of Plexiglas plates, between which the algae mass and nutrient solution are placed, is jagged – and is thereby about four times the size of the surface on which the reactor is standing. The vertical orientation of the plates and their jagged form provide for an incidence of light that is optimal for algae growth. [5]
Read more about the project here.
Bacteria-powered battery
There are a great many different approaches to investigating bacteria as potential energy suppliers. A student project currently taking place at Technische Universität Berlin is seeking to get bacteria to generate and transmit electricity in a bio-battery. The goal of the interdisciplinary Smart B.O.B. (Smart Biologically Optimized Battery) team is to make this happen at close to zero energy loss.
For this purpose, the scientists are making use of the natural flow of electrons – that is, electricity – in microbes. Some species of bacteria emit electrons into the environment. In this way, they release energy. The researchers are hoping to combine this ability with the properties of other bacterial species by means of genetic engineering. For example, certain protein complexes from the Shewanella oneidensis bacteria are to be introduced into cyanobacteria in order to transmit the electrons produced during photosynthesis to an electrode on the outside of the bacteria, where the electric current can then be used. [6]
Learn more about the project here.
Another example of energy generation by bacteria is “MolkeKraft”, a joint project by the Helmholtz Centre for Environmental Research (UFZ) and the Center for Applied Geoscience (ZAG) at Eberhard Karls Universität Tübingen: its goal is to use bio-oil produced by bacteria and further process it into aviation fuel. In Germany alone, the milk-processing industry annually produces around four million tonnes of – virtually unusable – acid whey as a by-product. Its disposal – that is, the treatment of the resulting waste water – consumes great amounts of energy. [7]
Blueprint for waste recycling of the future
The principle behind “MolkeKraft”: bacteria convert the sugar contained in the acid whey into lactic acid. In refineries, electrochemical processes are used to turn the organic acids into fuel and chemicals. According to the Federal Ministry of Education and Research, one of the sponsors of “MolkeKraft”, the project is intended to serve as a blueprint – for example for the utilisation of other types of waste. [8]
Which of the new technologies has a future as a practical application remains unclear. For instance, in order for hydrogen generated by micro-organisms to become a marketable fuel, there also needs to be infrastructure and storage facilities available besides the production processes. And there must be sufficient demand. One thing’s for sure: there is still a long way to go before microorganisms will start serving as hydrogen solar cells around the globe. [9]
Sources and bibliography
[1] https://www.mpi-bremen.de/Binaries/Binary2705/Aus-Zukunft-d.-Energie-2008.pdf
[2] https://www.mpg.de/8415420/Algen_Wasserstoff
[3] Publikationen.docx (email attachment Dr Oliver Lampret, Ruhr-Universität Bochum, AG Photobiotechnology, 17 January 2020)
[4] https://news.rub.de/wissenschaft/2019-11-04-biologie-wie-sauerstoff-das-herzstueck-wichtiger-enzyme-zerstoert, https://news.rub.de/presseinformationen/wissenschaft/2019-07-24-biologie-wie-die-natur-wasserstoff-produzierende-enzyme-baut, https://news.rub.de/presseinformationen/wissenschaft/2018-11-09-biologie-welchen-weg-protonen-nehmen
[5] https://www.kit-technology.de/de/technologieangebote/details/549/
[6] https://www.pressestelle.tu-berlin.de/menue/tub_medien/publikationen/medieninformationen/2019/juli_2019/medieninformation_nr_1222019
[7] https://www.ufz.de/index.php?de=46376
[8] https://www.validierungsfoerderung.de/validierungsprojekte/molkekraft
[9] https://www.deutschlandfunk.de/bio-solarzellen-mit-cyanobakterien-von-sonnenlicht-zu.676.de.html?dram:article_id=437690