The cultivation of C4 crops for the production of biofuels, as well as for food stock, is an area of growing interest as the world searches for sustainable alternatives to fossil fuels. Naturally adapted to hot, dry climates, C4s – a category which includes sorghum or millet, maize and sugar cane – are particularly effective at fixing CO2. Great Millet (a species of Sorghum from the sweet grass family) is one of the most promising because not only does it accumulate large amounts of sugar, it can be grown on marginal (difficult to cultivate) land and therefore doesn’t compete with other food production.

Now a new variant of millet called KIT1 has been developed at the Botanical Institute at the Karlsruhe Institute of Technology (KIT) by Dr Adnan Kanbar. The plant has been modified to synthesise particularly high quantities of sugar and it thrives in temperate as well as sunny environments.

The researchers at the Molecular Cell Biology Division working group headed by Professor Peter Nick are now investigating how it can be used for the production of biogas, biofuels and as a raw material for novel, eco-friendly polymers. They estimate that the sugar yield per hectare is 4.4 tonnes, which can be converted to 3,000 litres of ethanol. Furthermore, the biogenic waste material produced in the process can be used as a phosphate-free fertiliser. “Our study is the first one to look at the relationship between the structure of the vascular bundles and sugar accumulation in the stem,” says Nick in a media release.

The study, which was first published in the journal Industrial Crops & Products compares KIT1 sweet sorghum to Razinieh grain sorghum and details how sugar transport and sugar accumulation are related to the plants’ anatomy (it’s concentrated mainly in the stem and vessels). The study also found that KIT1 responded better to salinity stress testing – in other words, it can be grown in salty soils.