Fig. 5.

Effects of intermittent glucose addition on 2-KGA production. With an initial glucose concentration of 100 g L⁻¹, 60 g L⁻¹ glucose was intermittently fed several times when glucose was depleted. The titre of 2-KGA was 134.0 g L⁻¹ with a 77.7% conversion efficiency with intermittent feeding three times, higher than with two feeds (123.2 g L⁻¹ with a 71.4% conversion efficiency) and six feeds (113.5 g L⁻¹ with a 65.8% conversion efficiency). The significant differences about highest 2-KGA titre of modes of two/three intermittent additions compared to that of mode of six intermittent additions were analysed with T-test, p ≤ 0.01 was considered significant difference marked with a "*". (A) Two additions of 30 g L⁻¹ glucose each time. (B) Three additions of 20 g L⁻¹ glucose each time. (C) Six additions of 10 g L⁻¹ glucose each time. Squares = glucose, circles = D-GA, white triangles = OD₆₀₀ values, black triangles = 2-KGA.