Non-sterilized fermentation of high optically pure d-lactic acid by a genetically modified thermophilic Bacillus coagulans strain

Table 4 Comparison of d-lactic acid production by recombinants strains

Organism	Fermentation temperature (°C)	Fermentation mode	pH	d-Lactate concentration (g/L)	Total sugar addition	Yield (g/g)^a	Productivity (g/L/h)^b	Optical purity (%)	References
Saccharomyces cerevisiae	30	Batch	–	60	100 g/L (glucose)	0.65	2.8	99.9	[18]
Pediococcus acidilactici	42	SSF	–	97	25% (w/w, corn stover)	0.93	1.0	99.1	[24]
Lactobacillus plantarum	37	SSF	5.5–6.0	117	20% (w/v, brown rice)	0.93	0.8	99.6	[2]
Saccharomyces cerevisiae	30	Fed-batch	–	112	~190 g/L (glucose)	0.80	2.2	–	[25]
Escherichia coli	35	Batch	7.0	96	10% (w/v, sucrose)	0.93	2.6	> 99.5	[26]
Sporolactobacillus inulinus	42	Batch	5.0	93	100 g/L (glucose)	0.93	1.1	–	[27]
Bacillus sp.	54	Batch	6.5	28	50 g/L (sucrose)	0.96	–	99.5	[23]
Bacillus coagulans	50	Batch	5.0	90	110 g/L (glucose)	0.96	1.3	100	[12]
Bacillus coagulans	50	Batch	5.5–6.0	118	120 g/L (glucose)	0.98	2.0	99.6	This study
Bacillus coagulans	50	Fed-batch	5.5–6.0	145	150 g/L (glucose)	0.98	1.5	99.9	This study

SSF simultaneous saccharification and fermentation
^aYield (g/g) was calculated as the ratio of d-lactate produced (g) to consumed sugars (g)
^bProductivity (g/L/h) was calculated as the ratio of d-lactate concentration (g/L) to the fermentation time (h)

ISSN: 1475-2859