Biomass pretreatments

The use of recombinant microorganisms for cofermentation is one of the most promising approaches in the field of bioethanol production, though their use for large-scale industrial processes still requires fine-tuning of the reliability of the entire process (2). The technical hurdles of cofermentation increase when real biomass hydrolysates have to be fermented. In fact, whatever the biomass pretreatment, the formation of degradation byproducts that could inhibit the fermentation usually requires the addition of a further detoxification step. Therefore, the production of ethanol from hydrolysates should be considered in its entirety, from the optimal pretreatment to the choice of the proper fermentation process. 

Harvest the cellulase-containing transgenic plants at the end of the season, use biomass pretreatment to rupture plant cells to facilitate the release of enzyme, and then combine this material with lignocellulosic biomass in enzymatic hydrolysis. 

Schultz, T. R, Blermann, C. J., and McGinnis, G. D., Steam explosion of mixed hardwood chips as a biomass pretreatment. Industrial Engineering Chem Product Res Dev 1983, 22 (2), 344-348. 

AFEX [Ammonia Fiber Explosion (or Expansion)] A pretreatment process for ligno-cellulose prior to enzymatic conversion to ethanol. The wood is exposed to liquid ammonia at 60 to 100°C for a short time, and the pressure suddenly released. Invented in 1998 by B.E. Dale and M. Moniruzzaman at Texas A M University and further developed by Dale at Michigan State University. In 2006, AFEX was regarded as the leading nonenzymatic biomass pretreatment process. 

Ionic liquids have only just begun to be investigated for biomass related processes within the last 10 years, yet there are already many exciting examples of how they can be applied in this area. They have been used in cellulose functionalisation, thermochemical depolymerisation, enzymatic depolymerisation, extraction of biomass components, and biomass pretreatment processes. In a growing number of cases, ionic liquid processes have been patented, which suggests future commercial value. 

All sugar and lignin content based on the oven-dty untreated biomass. Pretreatment conditions 15wt% of... 

Many factors impact the xylose to xylitol fermentation process, including oxygen delivery rate and concentration, pH, temperature, and the presence of other sugars (in addition to xylose), nutrients, and inhibitors [4, 6]. The least studied of these factors is the effect of specific inhibitors derived from biomass pretreatment on the growth of xylitol-... 

E. Chornetr R.P. Overend and co-workers at the Universite de Sherbrooke have been working on a liquefaction process in pressurized solvent for some years. Their approach involves an overall integration of biomass pretreatment, fractionation, acid processing, thermochemical and biochemical treatment. 

Balan V, Bals B, Chundawat SPS, Marshall D, Dale BE, Mielenz JR. (2009). LignoceUulosic biomass pretreatment using APEX. Methods Mol Biol, 581,61-77. 

Dale BE, Ong RG. (2012). Energy, wealth, and human development why and how biomass pretreatment research must improve. Biotechnol Prog, 28(4), 893-898. 

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