Effect of mechanical disruption on the effectiveness of three reactors used for dilute acid pretreatment of corn stover Part 2: morphological and structural substrate analysis

Biotechnology for Biofuels

Peter N Ciesielski¹  Wei Wang¹  Xiaowen Chen²  Todd B Vinzant¹  Melvin P Tucker²  Stephen R Decker¹  Michael E Himmel¹  David K Johnson¹  Bryon S Donohoe¹ 

[1] Biosciences Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO, 80401, USA

[2] National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, USA

关键词: Nanofibrillation;    Delamination;    Quantitative image analysis;    Severity factor;    Dilute acid pretreatment;    Biomass conversion;   

Others  :  792939
DOI  :  10.1186/1754-6834-7-47

 received in 2013-11-27, accepted in 2014-03-17,  发布年份 2014

【 摘 要 】

Background

Lignocellulosic biomass is a renewable, naturally mass-produced form of stored solar energy. Thermochemical pretreatment processes have been developed to address the challenge of biomass recalcitrance, however the optimization, cost reduction, and scalability of these processes remain as obstacles to the adoption of biofuel production processes at the industrial scale. In this study, we demonstrate that the type of reactor in which pretreatment is carried out can profoundly alter the micro- and nanostructure of the pretreated materials and dramatically affect the subsequent efficiency, and thus cost, of enzymatic conversion of cellulose.

Results

Multi-scale microscopy and quantitative image analysis was used to investigate the impact of different biomass pretreatment reactor configurations on plant cell wall structure. We identify correlations between enzymatic digestibility and geometric descriptors derived from the image data. Corn stover feedstock was pretreated under the same nominal conditions for dilute acid pretreatment (2.0 wt% H₂SO₄, 160°C, 5 min) using three representative types of reactors: ZipperClave® (ZC), steam gun (SG), and horizontal screw (HS) reactors. After 96 h of enzymatic digestion, biomass treated in the SG and HS reactors achieved much higher cellulose conversions, 88% and 95%, respectively, compared to the conversion obtained using the ZC reactor (68%). Imaging at the micro- and nanoscales revealed that the superior performance of the SG and HS reactors could be explained by reduced particle size, cellular dislocation, increased surface roughness, delamination, and nanofibrillation generated within the biomass particles during pretreatment.

Conclusions

Increased cellular dislocation, surface roughness, delamination, and nanofibrillation revealed by direct observation of the micro- and nanoscale change in accessibility explains the superior performance of reactors that augment pretreatment with physical energy.

【 授权许可】

   
2014 Ciesielski et al.; licensee BioMed Central Ltd.

【 图 表 】

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