Carbon neutrality in biobutanol production through microbial fermentation technique from lignocellulosic materials – A biorefinery approach

Biobutanol is gaining more interest as advanced biofuel owing to its characteristics such as higher energy content, density and lesser corrosiveness. Deriving butanol from biological sources is an approach to attain carbon neutrality by exploiting renewable and sustainable reserves for biorefineries. Lignocellulosic materials are regarded as the suitable resources for the manufacture of butanol and several value-added products. The yield and quality of biobutanol largely rely on three factors, namely, the pretreatment of lignocellulosic feedstock, bioconversion methods adopted and the downstream oil upgradation. In the present report, a critical review on six pretreatment methods, namely, radiative treatment, ultrasonication, hydrothermal methods, organic solvation, ionic liquids solvation and biological treatment of distinct lignocellulosic materials along with their performance levels are presented. The recent strategies devised in the utilization and modification of yeast and bacterial strains for the biorefinery approach in the synthesis of biobutanol are described. The optimal butanol yield of 13.3 g/L was reported using from rice straw and mixed culture of Saccharomyces cerevisiae and Pichia species by enzymatic hydrolysis.