Microbes and solar power ‘could produce 10 times more food than plants’

Combining solar power and microbes could produce 10 times more protein than crops such as soya beans, according to a new study. The system would also have very little impact on the environment, the researchers said, in stark contrast to livestock farming which results in huge amounts of climate-heating gases as well as water pollution.

The concept uses electricity from solar panels and carbon dioxide from the air to create fuel for microbes, which are grown in bioreactor vats and then processed into dry protein powders. The process makes highly efficient use of land, water and fertiliser and could be deployed anywhere, not just in countries with strong sunshine or fertile soils, the scientists said.

Microbes are already used to make many common foods, such as bread, yoghurt, beer and Quorn. But other researchers said converting consumers to eating microbial protein might be difficult and that such foods may not be nutritionally complete.

The researchers used data on today’s technologies to calculate the efficiency of each step of the process, including capturing CO2 from the air and processing the microbes into food that people could eat. They found the microbial system used just 1% of the water needed by the crops and a small fraction of the fertiliser, most of which is wasted when used in fields.

The analysis estimated that the solar-microbial process could produce 15 tonnes of protein from each hectare (or per 2.5 acres) a year, enough to feed 520 people, which the scientists said was a conservative estimate. In comparison, a hectare of soya beans could produce 1.1 tonnes of protein, feeding 40 people. Even in countries with relatively low sunlight levels like the UK, microbial protein production was at least five times greater from each hectare than plants.

Leger said plants’ ability to photosynthesise is remarkable but, in terms of energy efficiency, staple crops only convert about 1% of solar energy into edible biomass. This is because plants have evolved to compete and reproduce as well as just grow, and use less of the solar light spectrum than photovoltaic panels.