Seed culture pre-adaptation of Bacillus coagulans MA-13 improves lactic acid production in simultaneous saccharification and fermentation

Table 1 Overview of recent studies on LA production in SSF using different B. coagulans strains

Strain	Biomass			Process						Lactic acid		References
Strain	Raw material	Pre-treatment	Detoxification	Seed culture medium	Fermentation set-up	Temperature (°C)	pH	Enzyme load	Process time (h)	LA avg. vol. productivity (g/(L h))	Yield (g/g)	References
MA-13	Wheat straw	H₂SO₄-steam explosion	–	SM-0%	SSF	55	5.5	10 FPU/g_WIS	30	1.11	1.23^a/1.24^b/0.27^c	This work
MA-13	Wheat straw	H₂SO₄-steam explosion	–	SM-30%	SSF	55	5.5	10 FPU/g_WIS	15	1.74	1.02^a/1.10^b/0.27^c	This work
DSM 2314	Birch wood	Steam explosion	Water washing	TSNT	SSF	50	5.5	2 mg/g_DM	120	0.35	0.79^b	[28]
CC17	Bagasse	Sulfite pulping	Water washing	GCY	Fed-batch SSF	50	5.0–5.5	10 FPU_cellulase/g_cellulose 120 U_xylanase/g_{hemicellulose}	120	0.92	0.72^b/0.60^d	[25]
LA204	Corn cob	NaOH	Water washing	YEX	Fed-batch SSF	50	6.0	30 (FPU/g_cellulose)	90	1.37	0.77^c	[29]
		NH₃-H₂O₂	Water washing						90	1.32	0.74^c
		NH₃-H₂O₂	–						72	1.10	0.43^c
LA204	Corn stover	NaOH	Water washing	GY or XY	Fed-batch SSF	50	6.0	30 (FPU/g_stover)	60	1.63	0.68^c	[26]
IPE22	Wheat straw	H₂SO₄-steam explosion	–	mMRS	SSCF	50	5.0	20 FPU/g_cellulose	60	0.43	0.46^c	[27]
DSM 2314	Wheat straw	Lime	–	GY	Fed-batch SSF	50	6.0	n.r.	55	0.68	0.43^c/0.81^d	[20]

DM dry matter, FPU filter paper unit, n.r. not reported, U unit; WIS water-insoluble solid
SM-0%; SM-30% Seed medium containing 0% and 30% hydrolysate, respectively (see composition in the paragraph “Strain and media”. )
mMRS modified MRS: 10 g/L peptone; 10 g/L beef extract; 5 g/L yeast extract; 2 g/L K₂HPO₄; 0.2 g/L MgSO₄_7H₂O; 0.05 g/L MnSO₄_4H₂O; 10 g/L glucose
GY 10 g/L glucose; 10 g/L yeast extract; 2 g/L (NH₄)₂HPO₄; 3.5 g/L (NH₄)₂SO₄; 10 g/L Bis–Tris; 0.02 g/L MgCl₂·6H₂0 and 0.1 g/L CaCl₂·2H₂0
TSNT 10 g/L tryptone; 5 g/L soytone; 3 g/L NaCl and 1 g/L Tween 80
GCY 20 g/L glucose; 2.5 g/L corn steep powder; 1 g/L yeast extract; 1 g/L NH₄Cl; 0.2 g/L MgSO₄ and 10 g/L CaCO₃
GY (or XY) 50 g/L glucose (or xylose) and 10 g/L yeast extract
YEX 10 g/L xylose and 10 g/L yeast extract
^ag of lactic acid/g of consumed glucose
^bg of lactic acid/g of glucose released from cellulose
^cg of lactic acid/g of total dry matter
^dg of lactic acid/g of total sugars released from the biomass

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