This represents a yield of 0.78 mol mol−1 on glucose and a productivity of 0.27 g liter−1 h−1. Furthermore, they investigated the effect of the nitrogen source, including, among others, peptone and ammonium sulfate, and reported final titers of 32.6 g liter−1 and 30.4 g liter−1, respectively, after 7 days of fermentation from 100 g liter−1 glucose