A panoramic view of technological landscape for bioethanol production from various generations of feedstocks
Arti Devi, Somvir Bajar, Priyanka Sihag, Zaheer Ud Din Sheikh, Anita Singh, Japleen Kaur, Narsi R. Bishnoi, Deepak Pant
Abstract
Bioethanol is an appropriate alternate energy option due to its renewable, nontoxic, environmentally friendly, and carbon-neutral nature. Depending upon various feedstocks, bioethanol is classified in different various generations. First-generation ethanol created a food vs fuel problem, which was overcome by second-generation, third-generation and fourth-generation ethanol. The considerable availability of lignocellulosic biomass makes it a suitable feedstock, however, its recalcitrant nature is the main hurdle in converting it to bioethanol. The present study gives a comprehensive assessment of global biofuel policies and the current status of ethanol production. Feedstocks for first-generation (sugar and starch-based), second-generation (lignocellulosic biomass and energy crops), third-generation (algal-based) and fourth-generation (genetically modified algal biomass or crops) are discussed in detail. The study also assessed the process for ethanol production from various feedstocks, besides giving a holestic background knowledge on the bioconversion process, factors affecting bioethanol production, and various microorganisms involved in the fermentation process. Biotechnological tools also play a pivotal role in enhancing process efficiency and product yield. In adddition, most significant development in the field of genetic engineering and adaptive evolution are also highlighted.