“…Finally, the bottles were filled up to 150 mL with nutrient solution and flushed with a mixture of 80% N 2 and 20% CO 2 to maintain the proper pH and anaerobic conditions. Each liter of the nutrient solution contained beef extract, 2.0 g; yeast extract, 1.0 g; peptone, 4.0 g; MgSO 4 Á7H 2 O, 1.0 g; FeSO 4 Á7H 2 O, 0.1 g; NaCl, 3.0 g; KH 2 PO 4 , 1.0 g; K 2 HPO 4 , 1.0 g; l-cysteine 0.5 g (Ren et al, 2008). The bottles were kept at 35°C in a temperature controlled water-bath and inverted twice per day manually.…”