Gasification vs. Microbial Fermentation
There are two approaches to breaking the cellulose chains into simple sugars – thermochemical and biochemical.Gasification breaks down biomass into synthesis gas -- H2, CO, ( + small amount) CH4 -- which can be burned like natural gas, converted catalytically to fuels, plastics, or chemicals, -- or fermented into alcohols.
Thermochemical conversion involves breaking down the biomass into a mixture of gasses and then converting the gasses into ethanol. Although thermochemical conversion is a relatively simple and well known technology, it is expensive and requires significant capital and energy expenditures.
Biochemical methods use enzymes to break down the cellulose chains. An analogy to this is a termite that utilizes enzymes to break wood into sugar. Other biochemical methods for breaking down cellulose chains can be some varieties bacteria and yeast which then also ferment the sugar into ethanol. _BiofuelsDigest
Gasification is ready to go, technologically, but requires up-front capital and technical expertise. It works for any carbonaceous material -- even cheap & dirty coal and garbage biomass. Dirty coal cleans up marvelously via gasification, and turns a nuisance mineral into a valuable energy. The same applies to garbage biomass -- which would otherwise be an expensive disposal problem.
Synthesis Energy Systems, Inc. (SES) has executed a revised license agreement with the Gas Technology Institute (GTI) for its U-GAS technology rights. The revised agreement expands the rights and further defines the terms for SES to sub-license U-GAS to third parties for coal, coal and biomass mixtures, or 100% biomass projects.The microbial energy approaches will all need feestock materials. Most will use biomass of some type.
...With the reliable operations of SES’ 95%-owned Hai Hua plant in China this year (earlier post), and its success gasifying difficult fuels such as high-ash coal washing wastes, a high-ash sub-bituminous coal and most recently a lignite coal, SES says it is seeing significant interest from companies in the US, China, India and Australia for licenses to use the technology for both biomass and coal applications. _GCC
Companies such as Mascoma, Amyris, Virent, LS9 and Qteros, to name a few, are discovering technologies that shorten the feedstocks to ethanol cycle into two steps. For example, Mascoma’s transformative technology uses yeast and bacteria to produce ethanol from non-food agricultural and forestry materials sources such as switchgrass, wood, and agricultural waste feedstocks. Amyris, a company we explored last month, transforms Brazilian cane into ethanol and requires eight times less energy than converting corn to ethanol. Amyris’ renewable diesel has little sulfur and creates less particulate, carbon monoxide and hydrocarbon-exhaust emissions than fossil fuels. _BFD