Exploring cocoa pod husks as a potential substrate for citric acid production by solid-state fermentation using Aspergillus niger mutant strain

Abstract

The aim of this work was to use the cocoa pod husks (CPHs) as a new substrate/support for citric acid (CA) production by Aspergillus niger strains in solid-state fermentation (SSF). Actually, CPH does not have a proper final destination, and its characteristics are suitable to be used as sole substrate in SSF for CA production. Partial physical-chemical characterization of CPHs showed interesting composition and potential for fungal growth. The mutant A. niger B6 – CCT 7717 was previously screened due to its great capacity of CA production. The peak of CA production 978.52 g kg−1 of dry CPHs was reached at 72 h with a yield of 88.70 % (dry CPHs) and a productivity of 13.59 g kg h−1, surpassing the highest reported rates of CA production. Great perspectives are viewed for this process.