A review on green liquid fuels for the transportation sector: a prospect of microbial solutions to climate change

Document Type: Review Paper


1 Faculty of Medicine and Health Sciences, Macquarie University, NSW, Australia.

2 Department of Microbial Biotechnology, School of Biology and Centre of Excellence in Phylogeny of Living Organisms, College of Science, University of Tehran, Tehran, Iran.

3 Department of Animal Sciences, Ohio State Agricultural Research and Development Center (OARDC), The Ohio State University, Wooster, USA.


Environmental deterioration, global climate change, and consequent increases in pollution-related health problems among populations have been attributed to growing consumption of fossil fuels in particular by the transportation sector. Hence, replacing these energy carriers, also known as major contributors of greenhouse gas emissions, with biofuels have been regarded as a solution to mitigate the above-mentioned challenges. On the other hand, efforts have been put into limiting the utilization of edible feedstocks for biofuels production, i.e., first generation biofuels, by promoting higher generations of these eco-friendly alternatives. In light of that, the present review is aimed at comprehensively assessing the role and importance of microorganisms such as bacteria and yeasts as catalysts for sustainable production of liquid biofuels including bioethanol, biomethanol, biobutanol, bio-ammonia, biokerosene, and bioglycerol. Various aspects of these biofuels, i.e., background, chemical synthesis, microbial production (including exploitation of wild and metabolically-engineered species), and product recovery as well as the derivatives produced from these biofuels which are used as fuel additives are thoroughly covered and critically discussed. Furthermore, the industrial features of these green liquid fuels including the industrial practices reported in the literature and the challenges faced as well as possible approaches to enhance these practices are presented.

Graphical Abstract

A review on green liquid fuels for the transportation sector: a prospect of microbial solutions to climate change


  • Microbial-based biofuel as a promising waste-to-energy technology has been scrutinized.
  • Microbial production of bio-jet fuel is possible through DSHC, AtJ, and GtL.
  • Future application of ammonia as bio-fuel requires special design of ICE. 
  • Cons and pros of microbial liquid fuels over gasoline have been outlined.
  • Conversion of microbial liquid fuel into fuel derivatives has been discussed.


[24] Bechtold, R., 1997. Alternative fuels for vehicle fleet demonstration program. Report of the New York State Energy Research and Development Authority, NYSERDA Report.

[40] Cheng, W.H., Kung, H.H., 1994. Methanol production and use. Marcel Dekker, New York.

[47] Cummins, L., 1989. Internal Fire. Revised ed. Society of Automotive Engineers, Incorporated, Warrendale, Pennsylvania.

[87] Hal, B., William, K., Scott, S., 1982. The forbidden fuel: Power alcohol in the twentieth century. Boyd Griffin, New York.

[95] Hardenberg, H.O., Morey, S., 1992. Samuel Morey and his atmospheric engine. Society of Automotive Engineers, Warrendale, Pennsylvania.

[99] Hester, A., 2000. Microbial glycerol. Ind. Bioprocess 22(4), 3-5.

[105] Hull, A., 2012. Technology for the production of fully synthetic aviation fuels, diesel and gasoline. Contribution to Solakonferansen. Stavanger.

[115] Johnston, G., 2013. Alcohol to jet (AtJ). Contribution to Paris Air Show. June 2013, Paris.

[131] Kroch, E., 1945. Ammonia–a fuel for motor buses. J. Inst. Pet. 31, 213-223.

[138] Latvala, V., Ketola, A., Oskanen, I., Koskenniemi, K., Laaksonen, M., Lensu, E., 2014. Method for producing ammonia or ammonium by fermentation. United States Patent, Application No.14/565,055.

[151] Mavinic, D.S., Lobanov, S., Koch, F.A., Farhana, S., 2019. Process for removal or recovery of ammonium nitrogen from wastewater streams. United States Patent 20190062172A1.

[165] Nibin, T., Sathiyagnanam, A., Sivaprakasam, S., Saravanan, C., 2005. Investigation on emission characteristics of a diesel engine using oxygenated fuel additive. IE (I) J. 86, 51-54.

[204] Schelling, H., Stroefer, E., Pinkos, R., Haunert, A., Tebben, G.D., Hasse, H., Blagov, S., 2005. Method for producing polyoxymethylene dimethyl ethers, U.P. 0207954A1, Google Patents.

[205] Schwarz, W., Gapes, J., 2006. Butanol-rediscovering a renewable fuel. BioWorld Europe 1, 16-19.

[220] Stockes, K., 2007. Ammonia construction record and comments on ammonia fuel. Proc. of the Ammonia–Sustainable, Emission Free Fuel Conference, October 15-16.

[232] Temchin, J., 2003. Analysis of market characteristics for conversion of liquid fueled turbines to methanol. The Methanol Foundation and Methanex, Inc.

[268] Zhuge, J., Liu, X., 1990. A glycerol recovery method for glycerol production by fermentation. Chinese Patent CN 1047532A.