Table 2.

Volumetric hydrogen productivity in the R. capsulatus photo-fermentation using a 50-mL bioreactor

Assay	C lactosea (g/L)a	C lactic acida (g/L)a	C/Nb	Productivity (mmol H2/L day)
1	5.50	0.58	Without MWPc	8.00 ± 1.40
			35:1	9.62 ± 2.42
			70:1	4.74 ± 1.35
2	5.10	12.30	Without MWP	10.16 ± 1.84
			35:1	6.94 ± 4.66
			70:1	11.24 ± 6.34
3	0.70	8.83	Without MWP	0.44 ± 0.32
			35:1	4.67 ± 0.07
			70:1	8.66 ± 9.14
4	9.10	8.80	Without MWP	14.33 ± 9.78
			35:1	11.43 ± 0.28
			70:1	8.93 ± 2.60

^aInitial concentration

^bCorrelation of carbon and nitrogen (based on the MWP)

^cMWP: milk whey permeate (from 86 to 92 % of lactose)