Emerging techniques in bioethanol production: from distillation to waste valorization

Ethanol production from biomass, especially waste biomass, and the use of such ethanol as fuel can reduce fossil fuel consumption and ameliorate the hidden costs of burning fossil fuels such as its environmental impact. However, bioethanol production suffers from several limitations such as being energy-intensive and generating a sizeable amount of waste. This review briefly describes the aspects related to bioethanol production and focuses on both theoretical and practical approaches for process improvements. Several green emerging distillation techniques, such as ohmic-assisted hydrodistillation, membrane-assisted distillation, and heat integrated techniques, are shown to be energy-saving alternatives to the conventional distillation processes. Besides, a number of valuable components, such as pectin and bioactive compounds (e.g., phenolic compounds), have been recently isolated from the waste materials of bioethanol plants through various environmentally friendly valorization methods. These emerging distillation and extraction techniques can be integrated to evolve a greener bioethanol production process in the future.