Production of Citric Acid in Basal Coffee Husk Medium by Aspergillus niger under Solid State Fermentation

Citric acid is the most important organic acid produced in tonnage by fermentation. In the present study Aspergillus niger is used for the production of citric acid in basal coffee husk medium under solid state fermentation. Addition of methanol (3% v/w) to coffee husk medium in optimum moisture 45%, pH 4.5 and supplemented with trace elements had shown significant improvement in citric acid production. 187.54g citric acid/kg dry coffee husk was accumulated at 72 h resulting in 78.14% and 83.36% conversions based on the amount sugar of initially present in coffee husk and sugar consumed during fermentation respectively, with 97.73% sugar utilization.