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Table 4 Saccharification yields, milling energy and energy efficiency of milled switchgrass samples at different enzyme loadings

From: Gaseous ammonia pretreatment lowers the required energy input for fine milling-enhanced enzymatic saccharification of switchgrass

Sample 7 mg enzyme/g (glucan + xylan) Energy input during fine milling (MJ/kg) Monomeric + oligomeric Glucose % theor. yield Glucose mass yield (kg/kg biomass) Energy efficiency (glucose mass yield/energy input) (MJ/kg) Monomeric + oligomeric Xylose % theor. yield Xylose mass yield (kg/kg biomass) Energy efficiency (xylose mass yield/energy input) (MJ/kg) Energy efficiency (glucose + xylose mass yield/energy input) (MJ/kg)
Union process attritor mill, 5 min 0.958 61.75 0.2334 0.244 81.13 0.1874 0.196 0.439
Hosokowa 2ACM Air-classifier mill 1.801 55.81 0.2110 0.117 74.56 0.1722 0.0957 0.213
Fluid energy model 4 microjet, jet mill 5.40 57.06 0.2157 0.0399 75.74 0.1750 0.0461 0.0886
Kemutec 5H universal pin mill, 2 passages ND 53.57 0.2025   74.88 0.1730   
NH3-treated unmilled NA 49.58 0.1874   59.61 0.1377   
Sample 14 mg enzyme/g (glucan + xylan)
 Attritor mill 0.958 81.77 0.3091 0.323 91.81 0.2121 0.221 0.544
 Air-classifier mill 1.801 70.62 0.2669 0.148 83.18 0.1921 0.1068 0.255
 Jet mill 5.40 66 0.2495 0.0462 74.11 0.1712 0.0319 0.0779
 Pin mill, 2 passages ND 59.69 0.2256   73.46 0.1697   
 NH3-treated unmilled NA 57.09 0.2158   63.07 0.1457   
Sample 28 mg enzyme/g (glucan + xylan)
 Attritor mill 0.958 82.57 0.3121 0.326 87.36 0.2018 0.211 0.537
 Air-classifier mill 1.801 79.83 0.3018 0.168 87.65 0.2025 0.112 0.280
 Jet mill 5.40 76.31 0.2885 0.0534 85.23 0.1969 0.0365 0.0899
 Pin mill, 2 passages ND 72.54 0.2742   79.36 0.1833   
 NH3-treated unmilled NA 61.89 0.2339   64.21 0.1483   
  1. Saccharification yields and milling energies for milling trials on UT-4b NH3-treated (150–160 °C, 1 h) switchgrass. Each of the samples was saccharified at a 25 % solids loading for 120 h with three different concentrations of Accellerase® DUET at 7, 14 and 28 mg protein/g (glucan + xylan). The sugar yields are based on soluble monomer plus oligomer