Recent advances in bioethanol production from Lignocellulosic biomass

ABSTRACT

The field of bioethanol production has seen rapid advancements in the past few decades. Despite the advancements, bioethanol production’s recent trends cannot prove effective and efficient transportation fuel. Fossil fuels, which currently power-ups most energy demands, from nonrenewable energies, meaning it will bring adverse effects to the environment, including ozone layer depletion and global warming. It makes bioethanol the best alternative to fossil fuels, owing to the fact than it is considered carbon-neutral. In some parts of the world, bioethanol is utilized as an alternative fuel by using the lignocellulosic (LC) residues, and prioritizing its production as better feedstocks available could fulfill the void created in the transportation fuel sector. Separate hydrolysis and co-fermentation (SSCF) and Pre-hydrolysis and simultaneous saccharification and co-fermentation (PSSCF) are superior to all techniques to achieve saccharification, hexose, and pentose fermentation in a one-pot reaction. For the feedstock modification, the genome engineering and cell wall modification are advanced methods so far. As of not long ago, there is no cost-effective and financially achievable pretreatment technique for the removal of lignin that could be industrialized to satisfy the worldwide requirement for bioethanol. In this review we provide the present scenario of energy demand and advancement on bioethanol technology and challenges. Mainly, altering the LC biomass composition, the robust enzyme that enables to hydrolyzed and maximum fermentable sugar yield, and effectively fermenting bacteria and yeast, which is genetically engineered for simultaneous fermentation with the high rate, is future stepping research which should be emphasized in the bioethanol industry.

Graphical abstract

KEYWORDS:

• Alternative fuel
• Bioethanol
• Robust enzyme
• Thermotolerant yeast
• Future model

List of abbreviation

Mtoe: Millions tonnes of oil equivalent; LPG: Liquefied petroleum gas; NGV: Natural gas vehicle; RFA: Renewable fuel association; SGB: Second-generation bioethanol; LC: Lignocellulosic; 1G: First generation; 2G: Second-generation; 3G: Third generation; 4G: Fourth-generation; HMF: Hydroxymethylfurfural; SHF: Separate hydrolysis and fermentation; SSF: Simultaneous hydrolysis and fermentation; SSCF: Separate hydrolysis and co-fermentation; PSSCF: Pre-hydrolysis and simultaneous saccharification and co-fermentation; CBP: Consolidated bioprocessing; DP: Degree of polymerization; SGC: Synthetic genetic circuits; CRISPR: Clustered regularly interspaced short palindromic repeats; COMT: Caffeic-acid O-methyl transferase; LHW: Liquid hot water; Mpa: Mega pascal; AFEX: Ammonia fiber explosion; FPase: Filter paper activity; NREL: National renewable energy laboratory.

Disclosure statement

The authors declare that there is no conflict of interest regarding the publication of this paper.

Additional information

Funding

The authors have no funding to report.