Second generation biofuels and chemicals produced from plant waste are important renewable energy sources reducing our dependency on fossil fuels and greenhouse gas emissions. With the help of bacteria, cheap municipal and agricultural wastes, such as brewery waste or non-food crops, are turned into valuable chemicals. The photo depicts a colony of Geobacillus thermoglucosidasius, a heat-loving bacterium that has been found living in compost heaps where it breaks down plant material to release sugars. In the middle of the compost heap at around 60°C and under oxygen-limited conditions this bacterium uses these sugars as energy and carbon sources to make lactate, formate, acetate, and ethanol. For industrial purposes, this organism has been modified using genetic and metabolic engineering. This redirects production pathways towards a more desirable product, such as ethanol, and allows the introduction of new pathways for novel products, such as butanol or terpenes, effectively creating a microbial factory.