A study conducted by campus chemistry professor Peidong Yang and his team of researchers found that a bacterium called Moorella thermoacetica is more efficient in producing solar fuels after being fed gold.

The increasing demand for sustainable and renewable energy prompted the development and use of nanotechnology to harness solar power, according to the study, which was published in Nature Nanotechnology, a scientific journal, on Oct. 1.

“The utilization of traditional fossil fuels presents significant economic and societal issues,” said UC Berkeley graduate student Hao Zhang, who was a researcher on Yang’s team, in an email. “In order to keep up with growing energy dependence and overcome the limitations of fossil fuels, we must seek new approaches to create renewable and sustainable energies.”

Yang conducted a different study on the same bacterium in 2016, which found Moorella thermoacetica to be the first nonphotosensitive bacterium that can undergo artificial photosynthesis. This study led to the discovery of using the bacterium to create renewable and sustainable energy from its production of useful chemicals.

The research team’s recent findings indicate that Moorella thermoacetica can convert sunlight and carbon dioxide into chemicals that can be used for solar fuels. This allows for a higher yield of chemical products to be produced than what was previously found in the 2016 study.

“We aim to design the photosynthetic biohybrid systems (PBSs), which could link preassembled biosynthetic pathways with inorganic light absorbers, to efficiently convert CO2 into value-added products,” Zhang said in an email.

Advanced nanotechnology is inspired by the reliability of storing solar energy in chemical bonds seen in natural photosynthesis, according to Zhang.

Zhang said the team overcame the “sluggish kinetics” of extracellular electron transfer by photosensitizing the bacterium with gold. As a nonphotosynthetic bacterium, the Moorella thermoacetica is able to accept electrons from semiconducting materials and integrate them into metabolic processes.

“Intracellular PBS represents a promising platform to investigate the charge transfer,” Zhang said in an email.

Yang’s research team has worked on photosynthetic biohybrid systems since 2010, and this particular study of the Moorella thermoacetica took about three years of research, Zhang said. The study was funded by the National Institutes of Health, according to an article on the UC Berkeley College of Chemistry’s website.

The research team consisted of Zhang, Hao Liu, Zhiquan Tian, Dylan Lu, Yi Yu, Stefano Cestellos-Blanco and Kelsey Sakimoto.

Zhang said she felt inspired by Yang’s advice during her research experience. She said Yang helped the team think critically and be actively engaged in group project discussions, encouraging them to constantly ask themselves questions.

“Working with Peidong (Yang) is absolutely a happy experience,” Zhang said in an email. “He leads us to do the brainstorming and discusses advanced frontiers and new ideas with us often.”