Extraction of ferulic acid from agro-industrial wastes and evaluation of bioconversion of ferulic acid to vanillin by Streptomyces setonii

Several agro-industrial wastes (as chestnut and pistachio shells, grass, leaf fruit, vine leaf,and, red and white grape stems) were evaluated to ferulic acid extraction. The chemical analysis of these raw materials shows a high content of xylan in pistachio shells (33%), following the biorefinery concept, this fraction can be used in xylitol manufacture. The lignocellulosic materials were submitted to an alkaline extraction to obtain phenolic compounds, reaching a concentration of 312 mg ferulic acid/L in grass wastes. Other phenolic compounds were also extracted (gallic acid, p-coumaric acid, syringic acid etc.) depending of used raw material. Besides, the ferulic fermentation into vanillin was assayed. The higher concentration of vainillin (2692 mg/L) was achieved at 27 h (QP = 99.704 mg/L·h and YP/S = 0.50 mg/mg) using Streptomyces setonii