Use of Raman spectroscopy for continuous monitoring and control of lignocellulosic biorefinery processes

The production of fuels and chemicals from lignocellulosic biomass demands efficient processes to compete with fossil fuel-derived products. Key biorefinery processes, such as enzymatic hydrolysis of cellulose and microbial fermentation, can be monitored by advanced sensors in real time, providing information about reactant and product concentration, contamination, and reaction progress. Spectroscopic techniques such as Raman spectroscopy provide a means of quickly and accurately assessing many types of reaction mixtures non-destructively, in real time, and with no costly sample preparation and analysis time. Raman spectroscopy techniques have been developed to accurately quantify a number of compounds present in lignocellulosic processes, and methods have been developed to overcome the presence of fluorescent compounds that can increase the spectral background. Online Raman sensors also can provide the feedback measurements necessary for advanced process controls (APCs). Specifically, model predictive control, a common APC used extensively throughout similar processing industries, is especially well suited for ensuring optimal production of bio-based chemicals from lignocellulosic material.