In related work, continuous fermentation using spruce enzymatic hydrolysate showed 4.6 times higher productivity values under high cell density conditions (Palmqvist et al. 1998).
These values are the highest productivity values obtained among the values from design experiments.
Maximal productivities represent the highest productivity values between two consecutive time points.
The defined process was successfully validated, which yielded 4.50 HU/mL/min, one of the highest productivity values obtained compared with the productivities of the experimental design and with reduced operational costs.
Productivity comparisons calculated as amount of refolded protein per reactor volume and process time showed that an optimal refolding concentration to achieve highest productivity value is a balance between a rational reactor volume and a reasonable refolding time.
However, this integrated process did not surpass yield values obtained in a stirred tank fermentor when fumaric acid fermentation was controlled by CaCO3 under pressure pulsation (see previous section), but a higher productivity value of 1.09 g L−1 h−1 was reached (Zhou et al. 2000).
But only high water productivity values carry little or no interest if they are not associated with high or acceptable yields.
The highest volumetric productivity values (QEtOH (0 4 h), 1 2 g/l/h) were achieved with the Tembec and LYCC 6469 strains.
In opposition, the river community, that reached higher specific productivity values, seems to be a well-adapted community, which probably has a large supply of oxygen available for aerobic metabolism.
Higher tolerance, productivity values and other positive industrial attributes have been reported for Z. mobilis, as reviewed previously [ 6].
