Citric acid is produced by the fermentation of suger by Aspergillus niger, Mucor sp. and yeast. Lactic acid (first organic acid to be fermented) is obtained by the activity of a number of bacteria like Streptococcus lactis, Lactobacillus delbreukii, L. bulgaricus over a variety of nutrient medium like hydrolysed corn, or potato starch, molasses etc. Gluconic acid is manufactured through the Penicillium purpurogenum.