摘要

将生物质转化为生物燃料

作者(年代):Anil出差费

能源价格的上涨和化石燃料储备的枯竭继续引起人们对将生物质转化为生物燃料生产的兴趣。从可再生原料中提取的生物燃料是环境友好型燃料，到2050年有可能满足世界四分之一以上的交通燃料需求。此外，生物燃料预计将减少对进口石油的依赖，减少温室气体排放，并通过创造就业机会和提高生物产品的需求和价格来刺激地区经济。像乙醇这样的生物燃料是从粮食作物、生物质或木质纤维素材料中通过生化和热化学转化过程获得的。第一代生物燃料(即玉米乙醇和生物柴油)主要由粮食作物，如谷物，甘蔗作物和油料种子制成。从可食用糖和淀粉中生产第一代生物燃料的技术已经成熟并被广泛理解，生产主要受到环境和社会问题的限制，例如对用于食品和纤维生产的土地和水的竞争，导致世界食品和动物饲料的商品价格上涨(Sims et al. 2010)。由于这些重要的限制，“下一代”或第二代和第三代生物燃料正在使用先进技术从不可食用的木质纤维素材料中开发出来。这些木质纤维素原料包括木质生物质和木材废料、作物残余物、专用能源作物，如柳枝稷、城市垃圾和藻类。这些下一代原料不直接与粮食生产竞争，通常可以在边缘或未使用的农田上生产。此外，木质纤维素生物质是一种丰富的可再生能源，有可能取代大部分常规能源，如化石燃料和天然气，用于未来生产液体生物燃料，改善环境效益。 As a result, lignocellulosic biomass holds promise as a feedstock for a bio refinery where sugars can be transformed into building-block chemicals through fermentation, enzymatic, and chemical transformations (Ragauskas et al. 2006).Lignocellulosic biomass is a composite structure of lignin, cellulose, and hemicellulose polymers. The efficient utilization of biomass for biofuels production requires a fractionation of biomass constituents into separate streams at maximum yields. However, a major barrier to lignocellulosic biomass utilization in any sugar platform bio refinery is its intrinsic resistance to deconstruction. This recalcitrance results from multiple factors including the heterogeneous nature of the polymer matrix, the complexity of lignin and hemicellulose spatial and chemical interactions, and the extensive hydrogen bonding of crystalline cellulose. Therefore, investigating plant cell wall biosynthesis to unravel the recalcitrant structure of lignocellulosic biomass, exploring the types of pretreatment processes used to deconstruct biomass, and developing efficient enzymatic hydrolysis are main focus areas in converting the polymeric carbohydrates present in plant biomass to fermentable sugars for cost-effective ethanol production.