Development of an ammonia pretreatment that creates synergies between biorefineries and advanced biomass logistics models

• Published in: Green chemistry : an international journal and green chemistry resource : GC Vol. 24; no. 11; pp. 4443 - 4462
• Main Authors: Morais, Ana Rita C, Zhang, Jian, Dong, Hui, Otto, William G, Mokomele, Thapelo, Hodge, David, Balan, Venkatesh, Dale, Bruce E, Lukasik, Rafal M, da Costa Sousa, Leonardo
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 06.06.2022; Royal Society of Chemistry (RSC)
• Subjects: Ammonia; Bagasse; Biomass; Biorefineries; Carbohydrates; Ethanol; Glucan; Green chemistry; Hardwoods; Lignocellulose; Logistics; Pretreatment; Refining; Sugar; Sugarcane; Yield
• ISSN: 1463-9262; 1463-9270
• DOI: 10.1039/d2gc00488g

A novel ammonia-based pretreatment for densified lignocellulosic biomass was developed to reduce ammonia usage and integrate with viable biomass logistics scenarios. The COmpacted Biomass with Recycled Ammonia (COBRA) pretreatment performed at 100 °C allows >95% conversion of sugarcane bagasse (SCB) carbohydrates into soluble monomeric and oligomeric sugars (glucose and xylose) using industrially relevant 6% glucan loading (∼21% solids loading) enzymatic hydrolysis conditions at reduced enzyme loadings. Pretreatment via COBRA with simultaneous lignin extraction (COBRA-LE) improved Saccharomyces cerevisiae 424A(LNH-ST) metabolic yield from 89% to 97.5% relative to COBRA without delignification, allowing a process ethanol yield of 71.6%. A technoeconomic analysis on SCB biorefining to ethanol in the state of São Paulo, Brazil, compared COBRA to other mature technologies, such as AFEX and steam-explosion. Amongst all scenarios studied, biorefineries based on COBRA-LE pretreatment offered the lowest average minimum ethanol selling price of US$1.45 per gallon ethanol. COBRA pretreatment was subsequently tested on perennial grasses and hardwoods, and >80% total sugar yields were achieved for all cases. Biomass densification allows economic long-distance hauling and enables mega-biorefineries that benefit from economies of scale. COBRA-LE pretreatment uses densified biomass to achieve near-theoretical conversion of carbohydrates and usable lignin.