Production of citric acid from sugars present in wood hemicellulose using Aspergillus niger and Saccharomycopsis lipolytica

One strain each of the fungus, Aspergillus niger , and the yeast, Saccharomycopsis lipolytica , were investigated for their ability to produce citric acid from the sugars present in hemicellulose hydrolysates. S. lipolytica produced citric acid as efficiently from mannose as from glucose, but failed to assimilate xylose, arabinose or galactose. A. niger readily assimilated mannose, xylose and arabinose, and produced citric acid from these sugars although the yields were lower than from glucose. A possible inhibitory effect of arabinose on citric acid production from other sugars was observed using A. niger .