Lignocellulose to Biofuels: Membranes for Process Intensification

Lignocellulose to biofuels: membranes for process intensification

Membrane based processes are often attractive as they can frequently lead to tremendous levels of process intensification.  This is particularly important in the development of sustainable manufacturing processes.  This presentation focuses on the conversion of lingnocellulosic biomass to biofuels and chemicals, where development of cost efficient manufacturing processes are essential.  The figure below gives the glucose concentration as a function of time for a both a batch and continuous process (left hand side y-axis), as well as the rate of glucose production (right hand side y-axis) for enzymatic hydrolysis of cellulose.  As can be seen in the continuous process the rate of glucose production is several times higher than for the batch process but the glucose concentration is almost10 times lower. This is due to product inhibition of the enzyme

A membrane reactor with an appropriate pore size could lead to continuous removal of glucose in the permeate as it is produced.  Thus the rate of glucose production will be maximized.  However it will be essential to concentrate the glucose prior to further biochemical or thermochemical, processing.  Here results are presented for a submerged membrane reactor that enables continuous enzymatic hydrolysis.  Development of such a process can lead to more rapid hydrolysis and smaller reactor volumes. 

Finally we have developed a unique catalytic membrane that not only enables removal of glucose as it is produced, but also catalyzes the hydrolysis of cellulose in one step.  As cellulase enzyme continues to represent one of the most expensive components in the production of biofuels and chemicals, replacement of the enzyme is highly desirable.  Using our results for the hydrolysis of cellulose, the tremendous potential of membranes for process intensification will be discussed.

Variation of glucose concentration and glucose production rate as a function of time for batch and continuous processing.