Biotechnological approaches for l-ascorbic acid production

Over the past decade there has been increasing pressure to develop alternatives to the Reichstein process, a largely chemical synthesis by which the vast majority of world vitamin C (l-ascorbic acid, l-AA) is produced. The pressures include increasing environmental concerns and legislation, and the need to increase process efficiency and reduce capital costs. The development of efficient fermentation processes in the past ten years has also represented a catalyst for change. Here, we describe the development of biotechnological alternatives for the synthesis of Reichstein intermediates by industrial microorganisms. The recent elucidation of the plant biosynthetic pathway represents new opportunities not only for the direct synthesis of l-AA by fermentation but also for the production of human crop plants and animal fodder with enhanced nutritional value. We discuss the potential for these developments in the light of recent findings concerning l-AA biosynthesis in plants.