A breakthrough by the African Centre for Crop Improvement (ACCI) in the breeding of sorghum could have far-reaching implications for the biofuel and bioplastic industries in South Africa.
For the last decade, ACCI director Professor Mark Laing has been working on developing sorghum and sugar beet varieties, as part of an integrated package to provide crop material (feedstock) for these two industries. His interest in the project started about 15 years ago when the price of oil rose to $150 a barrel. "A large plastics company couldn’t get enough ethylene to make the quantities of polythene on order, so they wanted to start their own sugar-to-polythene plant and approached me about suitable sugar crops for the interior of South Africa," he says.
Three primary sugar crops are used in the production of biofuel: sugar cane, sorghum and sugar beet. Laing says sweet sorghum, which is naturally high in sugar, is drought tolerant and yields 100 tonnes per hectare at 13-18% sugar in six months, compared to sugarcane, which can only be grown in frost-free areas, takes one to two years to reach maturity and yields approximately 75 tonnes per hectare at 9-14% sugar in South Africa. Sugar beet is difficult from an agronomic perspective because it is a northern hemisphere crop, but the ACCI is developing varieties that can be grown in South Africa in winter. It has a sugar content of up to 24% and yields 50-75 tonnes per hectare in six months. Importantly, it is a winter crop and can be rotated with sorghum, which grows in summer, thereby providing year-round feedstock.
"Once we’ve got the hybrids and agronomy available it means that people can start up factories producing bioplastics and biofuels. That’s been my vision and sorghum and sugar beet are the best crops to do it. We can get 31 tonnes of sugar per hectare per annum if we plant these two crops for six months each," Laing noted.
The project has taken ten years to reach this point because sorghum is challenging to grow.
Source: acci.org.za.
