Characterization of a heat-tolerant Chlorella sp. GD mutant with enhanced photosynthetic CO2 fixation efficiency and its implication as lactic acid fermentation feedstock

Table 3 The time-course lactic acid production with Lactobacillus plantarum 23 and the consumption of glucose and xylose from hydrolysate of microalgal feedstock

Time (h)	Control	WT^a		M4^b		Lactic acid^c (g/L)
Time (h)	Glucose (g/L)	Glucose (g/L)	Xylose (g/L)	Glucose (g/L)	Xylose (g/L)	Control	WT	M4 mutant
0	20.5 ± 0.32	21.0 ± 0.33	1.9 ± 0.06	21.4 ± 0.29	2.1 ± 0.10	0	0	0
3	4.5 ± 0.17	2.65 ± 0.08	0.21 ± 0.00	2.75 ± 0.13	0.2 ± 0.01	11.60 ± 0.36	13.10 ± 0.54	13.45 ± 0.39
5	0	0	0	0	0	14.50 ± 0.28	16.10 ± 0.40	16.38 ± 0.62
8	0	0	0	0	0	14.40 ± 0.12	16.13 ± 0.08	16.45 ± 0.13
12	0	0	0	0	0	14.50 ± 0.12	16.13 ± 0.08	16.45 ± 0.13
24	0	0	0	0	0	14.50 ± 0.12	16.13 ± 0.08	16.45 ± 0.13
Conversion rate^d (%)						74.87	80.42	79.17

The WT and M4 mutant feedstock was obtained after 8 days of culture under 6% CO₂ condition. Pure glucose (used as control) in the fermentation broth of the control test was 20.5 g/L and accordingly, the content of glucose in the hydrolysate of the wild type (WT) and M4 mutant in the fermentation broth was adjusted to around 21 g/L with a xylose content of around 2 g/L. The conversion rate is estimated as (lactic acid content/theoretical lactic acid content) × 100 after 24 h of fermentation. The data are presented as mean ± SD (n = 3)
^a47.15 g day wt. of WT feedstock in 1 L fermentative mixture
^b39.28 g day wt. of M4 feedstock in 1 L fermentative mixture
^cLactic acid in 1 L fermentative mixture
^d(Real lactic acid content/theoretical lactic acid content) × 100

ISSN: 2731-3654