Lignin in plant biomasses: comparative metrological assessment of the detergent fiber and the insoluble dietary fiber methods

The detergent fiber and the insoluble dietary fiber methods were compared to quantitate lignin in commelinid and non-commelinid magnoliophyta biomasses. This comparison was based on the precision of these methods and on the correlation between these methods. The present study showed that the insoluble dietary fiber method was more reliable to quantitate lignin because of its higher precision and smaller bias, as compared to the detergent fiber method. Nevertheless, the less tedious and resource consuming detergent fiber method can reliably be used to predict the results of the insoluble dietary fiber method with the correction factors determined in this paper. These correction factors of commelinid biomasses are distinctive of those of non-commelinid magnoliophyta biomasses. The lignin content should be corrected for protein-like compounds, otherwise lignin is significantly overestimated. Owing to these correction factors, the biofuel (e.g. cellulosic ethanol and biomethanation production), bio-based chemicals and feed sectors can use the detergent fiber method to rapidly and reliably estimate the available amounts of lignin of plant biomasses and rank them according to their suitability to be converted based on their lignin content.