Lignocellulosic materials are the most abundant renewable resource, which can be converted into fuel and chemicals. Unlike grain starch, the carbohydrates are not readily available for enzymatic hydrolysis due to recalcitrant and complex structure, and the composition of biomass. Pretreatment methods using physical, chemical, and biological principles are under various stages of investigation. Extrusion is a well-known technology in processed food, feed, and plastic industries, which is simple yet offers an effective technique for affecting physiochemical changes.

C. Karunanithy and K. Muthukumarappan, South Dakota State University, USA, studied the influence of extruder barrel temperature, screw speed, alkali concentration, and switchgrass particle size on sugar recovery. Statistical analyses revealed that all the independent variables had a significant contribution to glucose, xylose, and combined sugar recovery from switchgrass.
The studies resulted in a glucose, xylose, and combined sugar recovery of 90.5, 81.5, and 88 %, respectively.

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• Optimization of Alkali, Switchgrass, and Extruder Parameters for Maximum Sugar Recovery
  C. Karunanithy, K. Muthukumarappan,
  Chem. Eng. Technol. 2011, 34 (9).
  DOI: 10.1002/ceat.201000378