PV-driven Microbial Foods Can Produce Sustainable Agriculture: Study

A group of researchers has demonstrated that using solar energy to produce nutrient-rich microbes can have the twin benefits of increasing food production in an environmentally sustainable way.

Scientists at the Göttingen University in Germany examined large-scale production of microbial biomass by combining ground-mounted photovoltaics, air, water, and nutrients. Their findings were published in the paper “Photovoltaic-driven Microbial Protein Production Can Use Land and Sunlight More Efficiently than Conventional Crops” in the journal Proceedings of the National Academy of Sciences of the United States of America (PNAS).

Population growth and changes in dietary patterns place an ever-growing pressure on the environment. Feeding the world within sustainable boundaries therefore requires revolutionising the way we harness natural resources. The scientists believe that the cultivation of microbial biomass, which is rich in proteins as well as other nutrients, can play a vital role in achieving food security while mitigating the negative environmental footprint of agriculture.

Microbial biomass can be cultivated to yield protein-rich feed and food supplements, collectively termed single-cell protein (SCP). Yet, we still lack a quantitative comparison between traditional agriculture and photovoltaic-driven SCP systems in terms of land use and energetic efficiency, say the researchers.

In their paper, they analyse the energetic efficiency of harnessing solar energy to produce SCP from air and water. That is, solar power can be used for converting atmospheric CO2 derived from direct air capture into microbial biomass that can feed humans and animals. Their model includes photovoltaic electricity generation, direct air capture of carbon dioxide, electrosynthesis of an electron donor and/or carbon source for microbial growth (hydrogen, formate, or methanol), microbial cultivation, and the processing of biomass and proteins.

The researchers show that, per unit of land, SCP production can reach an over 10-fold higher protein yield and at least twice the caloric yield compared with any staple crop. Altogether, this quantitative analysis offers an assessment of the future potential of photovoltaic-driven microbial foods to supplement conventional agricultural production and support resource-efficient protein supply on a global scale. Thus, microbial foods, the researchers argue, outperform agricultural cultivation of staple crops in terms of caloric and protein yields per land area at all relevant solar irradiance levels.

These results suggest that microbial foods could substantially contribute to feeding a growing population and could assist in allocating future limited land resources, conclude the scientists.

The authors of the paper include Dorian Leger, Silvio Matassa, Elad Noor, Alon Shepon, Ron Milo, and Arren Bar-Even. The full paper can be accessed here.