BIOTECHNOLOGY FOR THE CONVERSION OF LIGNOCELLULOSICS

During the last three years most of the research on bioconversion of lignocellulosics has focussed on a process scheme where the substrate is first pretreated, usually by high pressure steam, prior to fractionation into its cellulose, hemicellulose and lignin components. The cellulosic rich fraction is then hydrolyzed enzymatically, followed by fermentation of the liberated sugars to ethanol, while the lignin and pentose sugar rich streams are treated separately. The progress in each of these areas is discussed. Round robin activities between the participating labs were used to provide more uniform methods of quantifying cellulase and xylanase enzyme activities. The various technoeconomic models developed by network members were used to identify probable process schemes and determine technical "bottlenecks". We could also identify which components of the process were the most cost-intensive and determine the levels at which further increases in yields and productivity would have little effect on the cost of the final product.