Biochemical degradation of lignocellulose is a complex process where the substrate is broken down with acids/bases, steam, and specialized enzymes. This works but has the issues that differences in biomass can through the whole system off, there can be high input costs associated, and some of the products may be harmful to the microbes then needed to convert the biochemical product into fuel. Thermochemical degradation directly gasifies the feedstock into syngas. Syngas made from lignocellulosic stock is primarily composed of H2 and CO, these are gaseous substrates with little “fuel” potential. Syngas can be turned into liquid fuel by one of two processes: either through chemical catalyst (Fischer-Tropsch) or by microbial catalysts in syngas fermentation. This article by Elsevier explains the differences between these two systems, comparing their viability. Although not currently economically viable, the microbial fermentation process shows strong promise, more so than the use of chemical catalysts. The process still needs to be refined in terms of syngas quality, and product recovery, as well as optimizing each step in the process, but it is still a runner in the list of possible solutions as to the future of fuel.
An alternative to complex cellulose degradation