Table 2.
SSF experiments performed with 20% DW pretreated bagasse using the enzyme cocktail GC220 at different enzyme dosages to monomerize sugars, and B. coagulans DSM2314 for fermentation to lactic acid
| SSF | Biomass liquefied with | Enzyme added %V/DW | Preculture | C La (g/l) | A La (g) | Qv,av (g/l/h) | Q v,max (g/l/h) | Y s/La (%) | Y Lc/La % | Time (h)a |
|---|---|---|---|---|---|---|---|---|---|---|
| Batch | Liquid fraction | 12.5 | Reference | 64.1 | 77.6 | 0.78 | 4.2 | 80 | 74 | 90 |
| Batch | Liquid fraction | 12.5 | Furfural | 74.6 | 91.7 | 0.92 | 4.2 | 94 | 87 | 90 |
| Batch | Water | 7.5–>10 | Furfural | 70.6 | 84.2 | 0.92 | 4.4 | 92 | 83 | 84 |
| Batch | Water | 15 | Furfural | 70.4 | 83.8 | 1.14 | 4.2 | 90 | 83 | 68 |
| Two-stage 9.5 h | Water | 15 | Furfural | 58.2 | 75.9 | 1.81 | 4.3 | 90 | 73 | 37 |
Either liquid fraction acquired after acid pretreatment or MilliQ water is used to solubilize the solids. As inoculum, either a preculture to which furfural was added was used, or a reference preculture was used which did not contain furfural. Addition of 20% DW bagasse fibres was either done as batch at the start of fermentation, or in two stages of 10% DW. Lactic acid was determined via HPLC
C LA concentration of lactic acid at the end of the SSF in g/l
A La total lactic acid produced in g
Q v,av average volumetric lactic acid productivity in g/l/h
Q v,max maximum volumetric lactic acid productivity in g/l/h
Y s/La estimated conversion efficiency of sugar monomers to lactic acid in W/W
Y Lc/La lactic acid production yield on total lignocellulosic sugars in W/W
aTotal fermentation time, from inoculation of SSF to reaching final lactic acid concentration