In the study, 12 cyanobacterial strains were examined for their capability to biosorb rare earth components, as a sustainable option for bioremediation and metal recovery.
The unique pressures of cyanobacteria exhibit a fast and effective “biosorption” of rare earth elements, making recycling possible.
Rare earth elements (REEs) are a set of 17 metal aspects that have similar chemical properties. As a result, the demand for REEs has seen a stable increase over the past few decades and is predicted to continue increasing through 2030.
Due to their scarcity and high demand, REEs can be rather costly. A kilogram of neodymium oxide currently has a price of around EUR200 (~$ 214), while terbium oxide is even more expensive at around EUR3,800 (~$ 4,073) for the very same amount. Presently, China holds a dominant position in the mining of REEs, with near-monopolistic control over the industry. A current discovery of appealing new REE deposits, estimated at over one million metric lots, was made in Kiruna, Sweden and made headings in January 2023.
Circular economy
The advantages of moving from an inefficient linear economy to a circular economy, where all resources are recycled and reused, are obvious. So could we recycle REEs more efficiently, too?
In Frontiers in Bioengineering and Biotechnology, German researchers showed that the response is yes: the biomass of some unique photosynthetic cyanobacteria can efficiently absorb REEs from wastewater, for instance, obtained from mining, metallurgy, or the recycling of e-waste. The taken in REEs can afterward be washed from the biomass and collected for reuse.
” Here we enhanced the conditions of REE uptake by the cyanobacterial biomass, and characterized the most crucial chemical systems for binding them. These cyanobacteria could be used in future environmentally friendly procedures for synchronised REE healing and treatment of commercial wastewater,” said Dr. Thomas Brück, a teacher at the Technical University of Munich and the research studys last author.
Highly specialist pressures of cyanobacteria
Biosorption is a metabolically passive process for the quick, reversible binding of ions from liquid options to biomass. Brück and coworkers measured the capacity for biosorption of the REEs lanthanum, cerium, neodymium, and terbium by 12 stress of cyanobacteria in lab culture.
The authors found that an uncharacterized brand-new species of Nostoc had the highest capability for biosorption of ions of these four REEs from liquid services, with effectiveness in between 84.2 and 91.5 mg per g biomass, while Scytonema hyalinum had the lowest efficiency at 15.5 to 21.2 mg per g. Also efficient were Synechococcus lengthens, Desmonostoc muscorum, Calothrix brevissima, and an uncharacterized new types of Komarekiella. Biosorption was found to depend strongly on acidity: it was greatest at a pH of between 5 and 6, and reduced gradually in more acid options. The process was most efficient when there was no competitors for the biosorption surface area on the cyanobacteria biomass from favorable ions of other, non-REE metals such as zinc, nickel, aluminum, or lead.
The authors utilized a method called infrared spectroscopy to identify which practical chemical groups in the biomass were primarily responsible for the biosorption of REEs.
” We discovered that biomass derived from cyanobacteria has excellent adsorption characteristics due to their high concentration of adversely charged sugar moieties, which bring carbonyl and carboxyl groups. These adversely charged parts draw in positively charged metal ions such as REEs, and support their attachment to the biomass,” stated first author Michael Paper, a scientist at the Technical University of Munich.
Efficient and fast, with terrific prospective for future applications
The authors conclude that biosorption of REEs by cyanobacteria is possible even at low concentrations of the metals. The process is likewise fast: for instance, the majority of cerium in solution was biosorbed within five minutes of starting the response.
” The cyanobacteria described here can adsorb amounts of REEs corresponding to up to 10% of their dry matter. Biosorption thus presents a financially and environmentally enhanced procedure for the circular recovery and reuse of rare earth metals from diluted industrial wastewater from the mining, electronic, and chemical-catalyst-producing sectors,” said Brück.
” This system is anticipated to become economically practical in the future, as the need and market value for REEs are likely to rise considerably in the coming years,” he forecasted.
Recommendation: “Rare earths stay with unusual cyanobacteria: Future capacity for bioremediation and recovery of rare earth components” by Michael Paper, Max Koch, Patrick Jung, Michael Lakatos, Tom Nilges and Thomas B. Brück, 28 February 2023, Frontiers in Bioengineering and Biotechnology.DOI: 10.3389/ fbioe.2023.1130939.
The research study was moneyed by the Bavarian State Ministry of the Environment and Consumer Protection, the Ministry of Science and Health Rhineland-Palatinate, the Federal Ministry of Education and Research, the German Research Council, and EU Horizon.
Uncommon earth aspects (REEs) are a set of 17 metal aspects that possess similar chemical properties. As a result, the need for REEs has seen a consistent rise over the previous couple of decades and is predicted to continue increasing through 2030.
Due to their shortage and high need, REEs can be quite pricey. A recent discovery of appealing brand-new REE deposits, approximated at over one million metric tons, was made in Kiruna, Sweden and made headlines in January 2023.
Brück and colleagues measured the potential for biosorption of the REEs lanthanum, cerium, neodymium, and terbium by 12 stress of cyanobacteria in laboratory culture.
