Scientists studied how adding different metals to bacteria that break down waste could help them produce more biogas—a renewable energy source. They tested 35 different setups with bacteria and added metals like tungsten, molybdenum, and selenium. The results showed that certain combinations of these metals helped the bacteria work better and produce more methane gas, which can be used for energy. This research could help waste treatment facilities make more clean energy from garbage and other organic waste.

The Quick Take

  • What they studied: Whether adding specific metals (tungsten, molybdenum, and selenium) to bacteria that digest waste could help them produce more biogas and methane energy
  • Who participated: 35 laboratory reactors (containers) filled with special bacteria that naturally break down organic waste without oxygen. These weren’t human studies—they were controlled experiments with microorganisms
  • Key finding: Adding tungsten combined with selenium, or tungsten alone, helped bacteria produce more methane gas. Selenium also made the bacteria’s protective coating stronger. Different metals changed which types of bacteria were present and how they worked
  • What it means for you: This research could eventually help waste treatment plants and farms produce more renewable energy from organic waste like manure and food scraps. However, this is early-stage lab research, so real-world applications are still years away

The Research Details

Researchers set up 35 small laboratory containers (called reactors) filled with special bacteria that break down organic material without oxygen—a process called anaerobic digestion. They added different combinations of metals to see how the bacteria would respond. Over 24 days, they measured how much methane gas was produced, what the bacteria looked like under a microscope, and which types of bacteria were present. Some containers were sacrificed (stopped and analyzed) at different time points to collect samples for detailed testing.

They used advanced laboratory techniques to identify which bacteria were present by analyzing their genetic material (DNA and RNA). They also measured how much of each metal stayed in the system and examined the protective coating that bacteria make around themselves. This protective coating is important because it helps bacteria survive and work together as a community.

Understanding how different metals affect the bacteria that produce biogas is important because biogas is a renewable energy source. If scientists can figure out the right combination of metals to add, waste treatment facilities could produce significantly more energy from the same amount of waste. This could make renewable energy more practical and cost-effective

This is a controlled laboratory study with 35 reactors, which is a reasonable sample size for this type of research. The researchers used multiple advanced techniques to measure their results, including genetic analysis and microscopy, which increases reliability. However, because this is lab-based research with bacteria in containers, the results may not directly translate to large-scale real-world waste treatment facilities. The study was published in a peer-reviewed scientific journal, meaning other experts reviewed it before publication

What the Results Show

When tungsten and selenium were added together, or tungsten alone, the bacteria produced significantly more methane gas compared to the control groups. Tungsten and molybdenum also helped the bacteria retain more iron, which is important for their survival and function.

Selenium had a special effect: it increased the amount of protein and carbohydrate content in the protective coating around the bacteria. This stronger coating may help the bacteria survive better and work more efficiently together.

The different metal combinations changed which types of bacteria were present in the system. Molybdenum and selenium had the biggest impact on shifting the bacterial community. Some bacteria that are normally dominant became less common, while others became more abundant.

Interestingly, the bacteria showed increased potential to produce important B vitamins (B12, B6, and B9) when certain metals were present. These vitamins are essential for many biological processes

The study found that molybdenum and tungsten increased the amount of soluble iron in the containers, even in setups without bacteria. This suggests these metals help iron stay in a form that bacteria can use. The research also showed that different metal combinations affected which metabolic pathways (the chemical processes bacteria use) were active. Specifically, nucleotide metabolism—the process bacteria use to build and repair genetic material—was enhanced with certain metal combinations

Previous research has shown that individual metals like molybdenum and selenium are important for anaerobic digestion, but this study is one of the first to systematically test how combinations of these metals work together. The findings support earlier work showing that trace metals are essential, but they go further by showing that the right combinations can have synergistic effects—meaning they work better together than separately. This aligns with the growing understanding that biogas production is a complex process requiring careful balance of multiple nutrients

This research was conducted only in laboratory containers, not in full-scale waste treatment facilities, so results may differ in real-world conditions. The study lasted only 24 days, which is relatively short for understanding long-term effects. The researchers didn’t test all possible combinations of metals, so there may be other beneficial combinations they didn’t discover. Additionally, the study didn’t include economic analysis, so we don’t know if adding these metals would be cost-effective in practice. The findings need to be validated at larger pilot scales before they can be reliably applied to industrial operations

The Bottom Line

Based on this research, waste treatment facilities and biogas producers may want to consider testing tungsten and selenium supplementation to potentially increase methane production (moderate confidence level—this is early-stage research). However, before making operational changes, facilities should conduct their own pilot studies to confirm these results apply to their specific waste streams and operating conditions. The cost-benefit analysis of adding these metals needs to be evaluated for each facility

This research is most relevant to: waste treatment plant operators, biogas production facilities, agricultural operations with manure management systems, and environmental engineers designing anaerobic digestion systems. It’s less immediately relevant to individual households, though the technology could eventually benefit them through improved renewable energy production. People interested in renewable energy and sustainable waste management should find this research interesting

If these findings are validated and applied to real facilities, improvements in biogas production could potentially be seen within weeks to months of implementing metal supplementation. However, the research-to-practice timeline is typically 3-5 years for environmental biotechnology innovations, as they require pilot testing, economic analysis, and regulatory approval before widespread adoption

Want to Apply This Research?

  • For facilities implementing this research: track daily methane production volume (in cubic meters or liters), metal supplementation amounts added (in milligrams per liter), and calculate the ratio of methane produced per unit of metal added to measure efficiency improvements over time
  • Facility operators could implement a weekly metal supplementation protocol, starting with tungsten and selenium additions at recommended doses, while monitoring methane output daily. They should maintain detailed logs of supplementation timing, amounts, and corresponding biogas production to identify optimal dosing patterns
  • Establish a baseline measurement of current methane production for 2-4 weeks before adding metals. Then implement metal supplementation and track weekly methane production for 8-12 weeks. Compare production rates before and after supplementation, adjusting metal doses based on results. Conduct quarterly bacterial community analysis (if resources allow) to ensure microbial health remains stable

This research is preliminary laboratory-based science and has not yet been tested at full commercial scale. The findings should not be implemented in operational facilities without additional pilot-scale validation specific to your waste stream and operating conditions. Consult with environmental engineers and biogas specialists before making changes to metal supplementation protocols. Metal additions must comply with all local environmental regulations and safety guidelines. Results may vary significantly depending on waste composition, temperature, pH, and other operating parameters not fully explored in this study. Always conduct your own risk assessment and cost-benefit analysis before implementation.