AsianScientist (Apr. 11, 2018) – A team of engineers from the National University of Singapore (NUS) has discovered an inexpensive method to produce biofuel using a naturally occurring bacterium. They reported their findings in Science Advances.
Biofuels produced from unprocessed cellulosic materials such as plant biomass, as well as agriculture, horticultural and organic waste, are expected to meet growing energy demands without increasing greenhouse gas emissions resulting from the burning of fossil fuels. These cellulosic materials are abundant, environmentally friendly and economically sustainable.
Among various types of biofuels, biobutanol offers a great promise as a petrol substitute because of its high energy density and superior properties. It can directly replace gasoline in car engines without any modification. However, commercial production of biobutanol has been hampered by the lack of potent microbes capable of converting cellulosic biomass into biofuels. Existing techniques are costly and require complicated chemical pre-treatment of raw materials.
In this study, a research team led by Associate Professor He Jianzhong from the Department of Civil and Environmental Engineering at the NUS Faculty of Engineering generated biofuels using a naturally occurring bacterium, Thermoanaerobacterium thermosaccharolyticum TG57 (TG57), isolated from waste generated after harvesting mushrooms. The bacterium is capable of directly converting cellulose, a plant-based material, to biobutanol.
“The production of biofuels using non-food feedstocks can improve sustainability and reduce costs greatly. In our study, we demonstrated a novel method of directly converting cellulose to biobutanol using the novel TG57 strain. This is a major breakthrough in metabolic engineering and exhibits a foundational milestone in sustainable and cost-effective production of renewable biofuels and chemicals,” said He.
Spent mushroom compost, typically composed of wheat straw and saw dust, is the residual waste generated by mushroom farming. The microorganisms in the waste were left to evolve naturally for more than two years to obtain the unique TG57 strain, said the researchers.
The scientists also noted that fermentation process is simple and no complicated pre-treatment or genetic modification of the microorganisms is required. When cellulose is added, the bacterium simply digests it to produce butanol as the main product.
Moving forward, the research team will continue to optimize the performance of the TG57 strain, and further engineer it to enhance biobutanol ratio and yield using molecular genetic tools.
The article can be found at: Li et al. (2018) Unique Genetic Cassettes in a Thermoanaerobacterium Contribute to Simultaneous Conversion of Cellulose and Monosugars into Butanol.
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Source: National University of Singapore.
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