FTIR assessment of compositional changes in lignocellulosic wastes during cultivation of Cyclocybe cylindracea mushrooms and use of chemometric models to predict production performance

Abstract

Solid-state fermentation of various lignocellulosic residues through the use of mushroom fungi leads to the production of edible/medicinal biomass. However, several aspects of this process remain obscure, while the potential exploitation of a wide range of agro-industrial wastes as mushroom substrates is of questionable usefulness. This study attempts to develop a fast and inexpensive method based on Fourier transform infrared (FTIR) spectroscopy for (a) determining compositional changes in lignocellulosic wastes used for the cultivation of Cyclocybe cylindracea mushrooms, (b) identifying compounds in substrates which are related to enhanced productivity and (c) developing a chemometric model through the use of multivariate analysis to predict biological efficiency in mushroom production process. High prediction scores were obtained (R2CAL: 0.95, R2CV: 0.70, RMSECV: 24%), while interpretation of regression coefficients was congruent to results of principal component analysis demonstrating a positive correlation of C. cylindracea biological efficiency values to the initial materials content in lignocellulosic compounds, and a negative correlation to their protein and phenolics content. The combined use of FTIR data and chemometrics provides valuable information on structural modifications of major substrate components during C. cylindracea growth and fructification, and could be exploited for evaluating substrates’ suitability prior to their use for mushroom cultivation.