Breaking through the cost barrier for ethanol production from straw

Thread Content

Following the establishment in 2006 of a demonstration project for the production of 3,000 tons per year of ethanol fuel derived from straw through enzymatic fermentation, Shandong Zesheng Biotechnology Co., Ltd. succeeded, thanks to its independent innovation efforts, in overcoming the bottlenecks that affected production costs in November 2007. This breakthrough enabled the economic viability of straw-based ethanol production: 1 ton of ethanol can be produced from 7 tons of straw, at a cost of 4,500 yuan per ton, which is 1,000 yuan less than the cost of producing ethanol from grain. Zesheng Biotechnology Co., Ltd. is working to increase its annual production capacity of fuel ethanol to 10,000 tons, and it is also actively preparing the preliminary work for a project aimed at producing 60,000 tons of fuel ethanol through the fermentation of straw per year. It is estimated that once the 60,000-ton project is completed, it will be able to consume 420,000 tons of straw per year, producing 60,000 tons of fuel ethanol, 10,000 tons of xylitol, 4,000 tons of xylitol oligosaccharides, and 60,000 tons of organic compound fertilizers, thereby generating an additional annual output value of 600 million yuan. The “New Technology for Enzymatic Hydrolysis and Fermentation of Straw to Produce Fuel Ethanol and Its Industrialization Demonstration Project”, developed by Zesheng Company in collaboration with the Institute of Process Engineering of the Chinese Academy of Sciences, was approved by an expert panel from the Chinese Academy of Sciences as early as 2006. This demonstration project utilizes a new solid-state fermentation technology with independent intellectual property rights, as well as a pollution-free steam explosion technique. It is a systematic, efficient, clean, safe, and feasible approach, providing a basis for scaling up the industrial production of fuel ethanol through the enzymatic fermentation of tens of thousands of tons of straw. This project has resulted in the construction of the largest 100m3 solid-state pure-strain fermentation bioreactor available both domestically and internationally, as well as a large-scale pollution-free steam explosion treatment system for straw. It also introduced a new technology featuring the triple coupling of straw solid-phase enzymatic hydrolysis, simultaneous fermentation, and adsorption separation, and successfully developed a reaction apparatus for this triple-coupling process with a capacity of 110m3. The products manufactured are competitive in the market, providing a production technology route that suits China’s national conditions for the industrial production of fuel ethanol via straw enzymatic fermentation, which holds great significance for China’s strategy of developing renewable energy sources on a sustainable basis. Industry experts believe that, given China’s national conditions, fuel ethanol will in the long term rely primarily on agricultural waste. This technology, jointly developed by the Institute of Process Engineering of the Chinese Academy of Sciences and Zesheng Company, represents a significant innovation that allows for production without competing with humans for land or with the land itself for crops, thus opening up new possibilities for the production of fuel ethanol. It is reported that this technology currently holds 35 patents, of which 15 are international patents.