Fig. 3
From: Direct conversion of cellulose to l-lactic acid by a novel thermophilic Caldicellulosiruptor strain
Effect of externally added lactic acid on growth of Caldicellulosiruptor DIB 104C wild-type strain and evolved strain clone 45. Bacteria were grown at 70 °C in 16 ml Hungate tubes with 9 ml medium containing 5 g/l glucose and 10 g/l MOPS. Lactic acid was added as sodium lactate to initial concentrations of 4.0 g/l (A), 15.5 g/l (B), 19.2 g/l (C) or 22.8 g/l (D). Growth was monitored by measurement of the optical density (McFarland units) of cultures directly in tubes using a densitometer DEN-1. One McFarland unit corresponds to an optical density OD550 of 1 when measured in 1-cm cuvettes