Focusing on the development of integrated biorefining systems for producing liquid fuels from non-grain biomasses such as straw, to provide technical support for improving the utilization and conversion efficiency of such biomass materials

Thread Content

Our country generates over 1 billion tons of straw each year. This straw was once considered agricultural waste that had to be burned, which not only polluted the environment but also wasted resources. If these straws are converted into liquid fuel, they can be turned from waste into treasure. At the parallel forum of the recently held 2026 Zhongguancun Forum annual meeting, namely the \"Enterprise Discovery and Innovation Forum,\" the issue of \"Microbial processes and metabolic regulation mechanisms for the production of liquid fuels from non-grain biomass\" proposed by Energy Group and SDIC was selected as one of the top ten fundamental scientific issues in the biotechnology field for central state-owned enterprises. This study focuses on the integrated biorefining system for producing liquid fuels from non-grain biomasses such as straw, systematically revealing the regulatory mechanisms of the synergistic degradation of the three key components in non-grain biomasses and the synthetic metabolic pathways involved in fuel production, thereby providing technical support for improving the utilization and conversion efficiency of such biomass feedstocks. 　　Non-grain alternatives are an essential path for biomanufacturing. “Biomanufacturing has become a **strategic priority, and the use of non-grain raw materials is a key issue that needs to be addressed urgently in this field.” ”said Tian Chaoguang, a researcher at the Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences. As the scale of China’s biomanufacturing industry continues to grow, the issue of insufficient raw material supply is becoming increasingly prominent. Using grains to produce industrial products is not sustainable; finding alternative non-grain raw materials has become the only way forward for the development of the biomanufacturing industry. 　　As a type of non-grain biomass, straw is an effective solution to the issue of insufficient raw material supply in the biomanufacturing industry. “After 20 years of continuous research on the fermentation and conversion of biomass such as straw, significant progress has been made; the key challenges have been largely identified, and we are now at a stage where it is possible to solve these problems and achieve industrial application. ”Tian Chaoguang explained. 　　What are the tangible benefits of using straw as a raw material for biomanufacturing? Tian Chaoguang did some calculations: China generates over 1 billion tons of straw each year, of which about 500 million tons can be used as biomass resources for biomanufacturing. If this material is used to produce ethanol, the output will exceed 100 million tons, which means that at least 100 million tons of oil imports can be reduced. This is of great significance for ensuring China’s energy security. At the same time, per ton of bioethanol, carbon dioxide emissions are reduced by over 80% compared to petrochemical fuels ； And 1 ton of cellulose ethanol can reduce emissions by about 2 tons of carbon dioxide, indicating a huge potential for emission reduction. 　　“The synergistic degradation of the three components is the key focus of research. After 20 years of development, two main approaches have emerged for producing liquid fuel from straw. The first route is a “three-stage” process—pre-treatment, enzymatic hydrolysis, and fermentation. Straw is hydrolyzed by cellulase to produce straw sugar, which is then fermented to generate products such as ethanol. Currently, several pilot plants around the world are exploring this technical approach; it is nearing industrialization, but profitability remains a challenge. Our country is generally in a follow-up stage in this area, and is rapidly catching up in terms of the level, production, and activity of cellulases. The second technical approach is the “one-step method” – utilizing microorganisms to directly ferment biomass into target products such as ethanol. This technical approach has better prospects but also greater challenges. Currently, countries are accelerating research and development, and companies and research institutions in our country have already begun pilot tests of this technology. 　　Both of these technical approaches have room for development, as well as challenges that need to be addressed. “The challenge of the three-stage technical approach lies in cost control during the saccharification process and quality control of the sugar solution. This is because the glycosylation process requires a large amount of cellulase, and the sugar solution contains pentose and hexose sugars as well as impurities such as furfural; microorganisms have poor ability to utilize pentose sugars, and impurities like furfural also inhibit microbial fermentation. “How to obtain high-quality and low-cost saccharification broth is the challenge that the ‘three-stage’ technical approach aims to solve. ”Tian Chaoguang said. 　　“The core challenge of the \"one-step method\" is how to achieve simultaneous degradation and fermentation of straw, as well as controlling the fermentation time, the fermentation concentration of the product, and the conversion rate of the materials. “Our team focuses on the ‘one-step’ technical approach; we are currently utilizing high-temperature cellulose-degrading fungal systems to carry out both cellulose degradation and fermentation at the same temperature. Through metabolic engineering, we aim to improve the efficiency of producing fuel ethanol from biomass through one-step fermentation and reduce costs. ”Tian Chaoguang said. 　　Tian Chaoguang said frankly, “The main components of non-grain biomass are the ‘three elements’, namely cellulose, hemicellulose, and lignin.” Regardless of the route, for bioenergy to be commercialized, it is necessary to overcome the challenge of utilizing lignin, the third major component. Only when all three components can be efficiently and synergistically decomposed and utilized can the economic viability of biofuels be ensured. ” 　　Industry collaboration boosts the feasibility of producing liquid fuels. Tian Chaoguang’s team is researching integrated biorefining technologies for producing liquid fuels from non-grain biomass. This technology focuses on elucidating, through systematic approaches, the microbial mechanisms underlying the synergistic degradation of cellulose, hemicellulose, and lignin – these three components in plant biomass. It also explores the regulatory patterns related to the synthetic metabolic pathways that lead to the formation of target products. Efficient cellulase systems are developed, and together with partner companies, equipment and technologies for the efficient pretreatment of non-food biomass feedstocks are created, thereby improving the efficiency of utilizing and converting such feedstocks and expanding the sources of raw materials for the biomanufacturing industry. 　　Currently, biofuels are in a critical phase of transitioning from technical development to industrial implementation. Tian Chaoguang suggested that **relevant support policies, such as a carbon tax, should be introduced to assist companies in collecting straw and producing biofuels. Efforts should also be made to promote the certification and industrial application of green and low-carbon technologies, so that the large-scale industrial use of liquid fuels derived from non-grain biomass can be achieved as soon as possible through the combined efforts of the entire industry chain.