Recent advances on ammonia-based pretreatments of lignocellulosic biomass

• Published in: Bioresource technology Vol. 298; p. 122446
• Main Authors: Zhao, Chao, Shao, Qianjun, Chundawat, Shishir P.S.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.02.2020
• Subjects: Ammonia; Biomass; Biorefinery; biorefining; cell walls; Cellulose; crystal structure; environmental impact; hemicellulose; Hydrolysis; Lignin; Lignocellulose; porosity; Pretreatment; saccharification; Technoeconomics; Technoeconomics; Ammonia; Biorefinery; Pretreatment; Lignocellulose
• ISSN: 0960-8524; 1873-2976; 1873-2976
• DOI: 10.1016/j.biortech.2019.122446

•Leading ammonia-based pretreatments for lignocellulosic biomass are reviewed.•Distinct ammonia pretreatments enhance enzymatic hydrolysis through different mechanisms.•The physicochemical mechanism of various ammonia-based pretreatments was discussed.•Technoeconomic and environmental analysis of ammonia pretreatments were discussed.•A two-staged biorefinery model combining hot water and ammonia pretreatment was proposed. Ammonia-based pretreatments have been extensively studied in the last decade as one of the leading pretreatment technologies for lignocellulose biorefining. Here, we discuss the key features and compare performances of several leading ammonia-based pretreatments (e.g., soaking in aqueous ammonia or SAA, ammonia recycled percolation or ARP, ammonia fiber expansion or AFEX, and extractive ammonia or EA). We provide detailed insight into the distinct physicochemical mechanisms employed during ammonia-based pretreatments and its impact on downstream bioprocesses (e.g., enzymatic saccharification); such as modification of cellulose crystallinity, lignin/hemicellulose structure, and other ultrastructural changes such as cell wall porosity. Lastly, a brief overview of process technoeconomics and environmental impacts are discussed, along with recommendations for future areas of research on ammonia-based pretreatments.