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Table 4 Parameters at aerobic growth of K. marxianus DSM 5422 in media with various sources of nitrogen in a stirred bioreactor

From: Efficient growth of Kluyveromyces marxianus biomass used as a biocatalyst in the sustainable production of ethyl acetate

Parameter Added sources of nitrogen…
   (NH 4 ) 2 SO 4 a Urea NH 4 OH (NH 4 ) 2 SO 4 + NH 4 OH (NH 4 ) 2 SO 4 + NH 4 OH
Added (NH4)2SO4 [g/L] 10 0 0 1 2
Added urea [g/L] 0 5 0 0 0
Added Na2SO4 [g/L] 0 0.4 0.4 0 0
Initial NH4-N content [g/L] 2.12 0.10 0.13 0.30 0.53
Initial urea-N content [g/L] 0.04 2.38 0.04 0.04 0.04
Maximum growth rate [h−1] 0.56 0.54 0.54 0.54 0.56
Consumed sugar [g] 45.2 44.7 44.3 44.8 44.9
Final cell concentration [g/L] 26.7 30.8 7.49 22.1 27.0
Formed biomass [g] 16.3 17.3 4.2 13.0 16.2
Overall Y X/S [g/g] 0.362 0.388 0.095 0.289 0.361
Final NH4-N content [g/L] 0.02 0.03 0.00 0.04 0.17
Final urea-N content [g/L] 0.00 0.00 0.00 0.00 0.00
Supplied 2 M NH4OH [mL] 0.0 0.0 0.0 24.8 39.8
Supplied ammonia-N [g] 0.000 0.000 0.000 0.694 1.114
Consumed NH4-N [g] 1.212 0.039 0.077 0.849 1.317
Consumed urea-N [g] 0.024 1.371 0.025 0.026 0.023
Consumed N [g] 1.236 1.410 0.102 0.875 1.340
Overall Y X/N [g/g] 13.2 12.3 41.2 14.9 12.1
Final N content, x N [mg/g] 76 81 24 67 83
Supplied 2 M KOH [mL/L] 82 10 0 0 0
Supplied KOH [gKOH/gX] 0.34 0.04 0.00 0.00 0.00
Consumed oxygen [g] 25.3 26.4 28.6 30.3 27.9
Formed CO2 [g] 35.1 37.2 41.2 42.5 39.0
Average RQ [mol/mol] 1.01 1.02 1.05 1.02 1.02
Maximum CEtOH,L [g/L] 1.8 1.8 <0.1 0.2 <0.1
  1. Final parameters are valid for 36 h of cultivation with exception of the process with NH4OH as the only added N source where the final parameters were determined for 40 h of cultivation; cultivation at conditions as stated in Figures 3 and 4.
  2. a Data in this column was in part taken from Urit et al. [10,11,14]; small deviations from the formerly published data are due to re-evaluation of basic data taking liquid sampling into account.