Solange Mussatto, Invited Assistant Professor at the Bioprocess Engineering Group at the Delft University of Technology, is specialist in the area of biomass conversion. Recently she published a book on “Biomass Fractionation Technologies for a Lignocellulosic Feedstock Based Biorefinery”, which provides the state-of-the-art in this area by covering the most important topics related to biomass pretreatment.
‘Pretreatment is an essential step in the overall process for biomass conversion to biobased products.In order to achieve an efficient utilization of biomass and to develop economical, robust, and reliable processes for a biorefinery, an effective pretreatment technology is essential’, Mussatto says.
‘To be attractive, pretreatment must be cost-effective by minimizing heat, power, and chemical requirements, avoiding the degradation of sugars (since this negatively impacts the fermentation step) and generating few wastes. Momentarily, only three methods are being used on a commercial scale: steam explosion, dilute acid and alkaline pretreatment. These methods are effective but also have disadvantages in terms of costs, being this step one of the most expensive in a biomass biorefinery. Apart from the ‘big 3’, more than 20 other pretreatment methods have been studied with the purpose of developing technologies less energy-intensive and less dependent on the use of chemicals. One of these options is hydrothermal pretreatment, using relatively moderate temperatures and high-pressure, but without chemical agents. Other interesting method is based on the use of CO2 under high-pressure conditions, which results in an inexpensive acid, clean and easy to recover after use by depressurization. These cleaner methods have to be scaled up in order to assess their true potential in terms of economics.’