The textbook "Citric Acid from Aspergillus Niger" offers a comprehensive analysis of the industrial production of citric acid using the fungus Aspergillus niger. It highlights the biochemical processes that lead to the accumulation of citric acid and examines the role of enzymes produced by Aspergillus niger. The book discusses the utilization of carbohydrate sources and the associated metabolic pathways, including the glycolytic pathway and the citric acid cycle. Furthermore, the study optimizes various fermentation parameters to maximize the efficiency of citric acid production from waste materials such as peels of sweet oranges, mangoes, and bananas. This research is significant for the food industry and other sectors that rely on citric acid.