Tobacco as a promising crop for low-carbon biorefinery

Energy crops play a vital role in meeting future energy and chemical demands while addressing climate change.However,the idealization of lowcarbon workflows and careful consideration of cost-benefit equations are crucial for their more sustainable implementation.Here,we propose tobacco as a promising energy crop because of its exceptional water solubility,mainly attributed to a high proportion of water-soluble carbohydrates and nitrogen,less lignocellulose,and the presence of acids.We then designed a strategy that maximizes biomass conversion into bio-based products while minimizing energy and material inputs.By autoclaving tobacco leaves in water,we obtained a nutrient-rich medium capable of supporting the growth of microorganisms and the production of bioproducts without the need for extensive pretreatment,hydrolysis,or additional supplements.Additionally,cultivating tobacco on barren lands can generate sufficient biomass to produce approximately 573 billion gallons of ethanol per year.This approach also leads to a reduction of greenhouse gas emissions by approximately 76%compared to traditional corn stover during biorefinery processes.Therefore,our study presents a novel and direct strategy that could significantly contribute to the goal of reducing carbon emissions and global sustainable development compared to traditional methods.

Engineering for life in toxicity:Key to industrializing microbial synthesis of high energy density fuels

With the growing demand for air transportation combined with global concerns about environmental issues and the instability and lack of renewability of the oil market,microbial production of high energy density fuels for jets(bio-jet fuels)has received more attention in recent years.Bio-jet fuels can be derived from both isoprenoids and fatty acids,and,additionally,aromatic hydrocarbons derived from expanded shikimate pathways are also candidates for jet fuels.Compared to fatty acid derivatives,most of isoprenoids and aromatic hydrocarbons used for jet fuels have higher density energies.However,they are also highly toxic to host microbes.The cytotoxicity induced during the synthesis of isoprenoid or shikimate pathway-derived biofuels remains one of the major obstacles for industrial production even though synthetic and systems biology approaches have reconstructed and optimized metabolic pathways for production of these bio-jet fuels.Here,we review recent developments in the production of known and potential jet fuels by microorganisms,with a focus on alleviating cytotoxicity caused by the final products,intermediates,and metabolic pathways.