Production of l(+)-lactic acid from acid pretreated sugarcane bagasse using Bacillus coagulans DSM2314 in a simultaneous saccharification and fermentation strategy

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)	Q_v,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

ISSN: 2731-3654