Bioethanol Production from Residual Biomass of Plants: Prospective and Challenges

Abstract

The transportation sector faces urgent challenges due to climate change and declining fossil fuel reserves, necessitating viable alternatives to petroleum. This article focuses on second-generation bioethanol production, which utilizes lignocellulosic biomass, offering a significant advancement over previous biofuel generations. Biomass containing Lignocellulose i.e., cellulose, hemicellulose and lignin, undergoes pretreatment, enzymatic hydrolysis, fermentation, distillation and dehydration for conversion. Pretreatment enhances carbohydrate accessibility and reduces inhibitors, while enzymatic hydrolysis releases fermentable sugars like glucose and xylose. However, hydrolysates may require detoxification before fermentation, because of inhibitors. Moreover, effective saccharification involves exogenous hemicellulases and cellulolytic enzymes. Genetically engineered microorganisms are essential for fermenting xylose, as conventional yeast cannot. Moreover, genetic engineering facilitates the acquisition of pentose-fermenting microorganisms by optimizing xylose utilization from the hydrolysate. Utilizing residual biomass for bioethanol production offers substantial potential as a renewable energy solution, capable of combating climate change, bolstering energy security and promoting rural development.