(629c) Advanced Cellulosic Biofuel Production Using Cellulosic Emulsions

As global temperatures rise, biofuels are essential sources of renewable energy to reduce greenhouse gas emissions. While corn starch ethanol has been instrumental towards establishing the biofuel industry, its expansion raises concerns of sustainability and competition with food production. Cellulosic biofuels derived from agricultural waste and dedicated energy crops are recognized as more sustainable alternatives. However, cellulosic biofuels have struggled to be economically solvent due to the slow rates and insufficient extent of cellulose hydrolysis achieved with current pretreatment methods, which leads to long process times, waste, and high cellulase enzyme costs. We developed a new pretreatment method for efficient cellulosic biofuel production using cellulosic emulsions that addresses this challenge. We found that preparing cellulose-coated oil-in-water emulsions increase the rate and extent of hydrolysis in simultaneous saccharification and fermentation (SSF) processes. Cellulose pretreated using this new technology hydrolyzes up to 40 times faster than microcrystalline cellulose and generates nearly theoretical yields of ethanol when applied in an emulsified SSF (eSSF) process. Furthermore, we demonstrate the transferability of the eSSF technology to other desired products and more complex systems. Using a strain of S. cerevisiae engineered with optogenetic regulators to produce the advanced biofuel isobutanol, we were able to produce cellulosic isobutanol in light-controlled eSSF. This technology addresses the main challenges of cellulosic biofuel production by shortening processing times, lowering enzyme costs, and serving as a flexible platform for the sustainable production of cellulosic biofuels and chemicals.