Production of organic acids by yeasts and filamentous fungi

Organic acids are broadly distributed in nature, and humans used them in their natural sources since the early ages, essentially for food and drink preparations. Organic acids are low-molecular-weight organic compounds with one or more acidic groups such as carboxyl, sulfonic, alcohol and thiol groups. These functional groups make organic acids key building block chemicals, which have huge markets and are still commonly refined from petroleum. Indeed, during the first half of the twentieth century, advances in chemical synthesis offered competitive manufacturing processes. This scenario changed starting from the 1990s when development of the industrial biotechnology field, environmental issues and the integration of biomasses processing industries, fermentation and downstream procedures, yielded improved economics for the biological pathways. In this chapter, we mainly review the aspects of current or piloting large-scale successful industrial processes for yeast or fungal organic acid productions. Perspectives are also reported.