TY  - JOUR
AU  - Medina, Miguel A. 
AU  - Belmares, Ruth E. 
AU  - Aguilera-Carbo, Antonio 
AU  - Rodriguez-Herrera, Raul 
AU  - Aguilar, Cristobal N. 
PY  - 2010
TI  - Fungal Culture Systems for Production of Antioxidant Phenolics Using Pecan Nut Shells as Sole Carbon Source
JF  - American Journal of Agricultural and Biological Sciences
VL  - 5
IS  - 3
DO  - 10.3844/ajabssp.2010.397.402
UR  - https://thescipub.com/abstract/ajabssp.2010.397.402
AB  - Problem statement: Many agro-industrial wastes have little or none utilization, when these
materials could be a very rich source of several value-added compounds, such as: the pecan nut shells,
which contain Antioxidant Phenolic (AP) molecules like tannins. Approach: In this study, a
bioprocess for the liberation of AP from Pecan Nut Shells (PNS) was described. A chemical
characterization of raw material was evaluated to determine polyphenolic content of PNS, among other
components. Several fungal culture systems were evaluated at 96 h fermentation processes and using
PNS as sole carbon source. Solid (SSC) and Submerged (SmC) fermentations were carried out using
three strains of Aspergillus niger. Culture medium was composed of a solid (10-50%) and a liquid (90-
50%) part in order to complete the 100% of the medium. Results: A high concentration (19%) of
tannins was found in PNS on a dry basis, from which condensed tannins and their monomers were
found as the main fraction (14%) of tannins of PNS, also on a dry basis. In the strain selection step,
Aspergillus niger GH1 showed better growth on pecan nut shells compared to A. niger PSH strain,
therefore, A. niger GH1 was used for later experiments. The highest concentration of AP was obtained
with SSC inoculated with spores of A. niger GH1 on the 40% of solids system and in 20% solids
system where, among the other systems both presented 114 mg TP g-1 of phenolics liberation at 24 h
of fermentation. PNS is an important source of catechin, being this kind of compound which can be
liberated in higher proportion compared to other phenolics compounds. Conclusion: This study
demonstrated that fermenting PNS represent a good alternative to both use residues and obtaining AP.