In this case (Fig. 1a), accumulated

In this case (Fig. 1a), accumulated hydrogen reached 0.107 mol in 48 h and hydrogen productivity reached 114.29 mmol H2/L d after 31 h, with 99% consumption of lactose. On the other hand,lactose addition did not provide increments in the target-product similarly to the previous assays (Conditions 3 and 4), with a reduction of 39.72% of lactose concentration after the sugar addition. Cell density varied from 0.49 to 1.2 gvs/L and after the sugar supplementation, the cell density stabilized in about 1.09 gvs/L.