FEWLS research is delighted to share the news that our latest article has been published online in Green Chemistry!
The article entitled “Development of an ammonia pretreatment that creates synergies between biorefineries and advanced biomass logistics models” talks about how lignocellulosic biomass densification at regional depots can not only facilitate the bioeconomy logistics, but also help unleash the full potential of ammonia pretreatment for reducing biomass recalcitrance. A new ammonia pretreatment method, denominated as COmpacted Biomass with Recycled Ammonia pretreatment, or simply COBRA, has been developed to pretreat densified biomass. COBRA pretreatment can modify the native crystal structure of cellulose to a more digestible cellulose III allomorph by cellulase enzymes, while simultaneously extracting lignin from the biomass with high selectivity. More importantly, COBRA pretreatment can achieve these critical cell wall modifications with a third of the ammonia loading used by Extractive Ammonia (EA) pretreatment, resulting in major energy and operation cost savings!
The efficacy of COBRA pretreatment was evaluated using sugarcane bagasse, which is an abundant residue from sugarcane mills, especially in Brazil’s bioethanol producing facilities. The developed pretreatment technology was able to convert over 95% of the carbohydrates present in sugarcane bagasse to monomeric and oligomeric sugars after enzymatic hydrolysis and a maximum of 72% process ethanol yield after fermentation, which could be improved by the development of new enzyme cocktails for reducing oligomeric sugar levels, for example. In fact, if we assume the conversion of all soluble oligomeric sugars to fermentable sugars, there is the potential to achieve a remarkable 88% process ethanol yield from all carbohydrates present in sugarcane bagasse after fermentation!
A robust pretreatment technology needs to be effective for a wide range of feedstock types. In this work, COBRA pretreatment proved to be highly effective for pretreating hardwood dicots like poplar, and herbaceous monocots like corn stover, sugarcane bagasse, prairie cordgrass and miscanthus.
To evaluate the economic potential of COBRA pretreatment-based biorefineries, we have implemented a bioeconomy model for the state of Sao Paulo, Brazil, where sugarcane bagasse produced in sugar mills is densified and dried prior to storage and transportation to “mega-biorefineries”, capable of processing up to 20,000 tons of densified biomass per day. A machine learning algorithm was used to optimize the bioeconomy model and generate the minimum biofuel price for COBRA pretreatment-based biorefineries, which were further compared with AFEX-, Steam Explosion- and EA-based biorefineries.
This publication was the result fruitful collaboration between researchers from The University of Kansas, Laboratorio Nacional de Energia e Geologia (LNEG) from Portugal, Universidade Nova de Lisboa from Portugal, Montana State University, Michigan State University, Stellenbosch University from South Africa, the East China University of Science and Technology, the University of Houston and the US DOE - Great Lakes Bioenergy Research Center (GLBRC).
The work has been published online as a 2022 HOT Article in the journal RSC Green Chemistry and will be highlighted in the front cover of the printed issue when it gets published. Stay tuned for more!
In the meantime, if you are interested to access the article online, please click here!