Ability of Aspergillus niger to tolerate metal ions and minerals in a solid-state fermentation system for the production of citric acid

摘要: Abstract Biosynthesis of citric acid by Aspergillus niger in molasses medium submerged and liquid surface fermentations is highly sensitive to the concentration trace elements present medium. Studies on production wheatbran a solid-state fermentation system, however, showed no such influence despite high concentrations metal ions total ash content wehatbran. In contrast, supplementation with additional amounts mineral as iron, copper, zinc, manganese, magnesium phosphorous was found be necessary for increased acid. All when used individually at an optimum level 1·4–1·9 times. However, only copper zinc were effective combination. Citric this combination 49·21 g/kg commercial 48 h against 22·49 g formed absence any added same time. These results indicate that advantage tolerating probably due gradients impaired transport conditions limited water availability.