Biotechnological production of alpha-keto acids: Current status and perspectives.

Alpha-keto (α-keto) acids are used widely in feeds, food additives, pharmaceuticals, and in chemical synthesis processes. Although most α-keto acids are currently produced by chemical synthesis, their biotechnological production from renewable carbohydrates is a promising new approach. In this mini-review, we first present the different types of α-keto acids as well as their applications; next, we summarize the recent progresses in the biotechnological production of some important α-keto acids; namely, pyruvate, α-ketoglutarate, α-ketoisovalerate, α-ketoisocaproate, phenylpyruvate, α-keto-γ-methylthiobutyrate, and 2,5-diketo-d-gluconate. Finally, we discuss the future prospects as well as favorable directions for the biotechnological production of keto acids that ultimately would be more environment-friendly and simpler compared with the production by chemical synthesis.