Propionate production by Bacteroidia gut bacteria and its dependence on substrate concentrations differs among species

Table 1 Product formation of six Bacteroides strains

Products [mM]
Yeast extract [ ±]	B. ce. CRE21	B. gra. XDT-1	B. int. 341	B. luti UasXn-3	B. xylan. XB1A	B. pro. SV434
Propionate
−	3.1 ± 0.09	8.0 ± 0.40	3.2 ± 0.17	2.3 ± 0.05	2.4 ± 0.15	12.7 ± 0.50
+	3.6 ± 0.16	8.8 ± 0.15	3.8 ± 0.16	2.1 ± 0.44	2.8 ± 0.07	13.8 ± 0.32
Acetate
−	8.0 ± 1.01	3.2 ± 0.12	8.4 ± 0.43	10.3 ± 0.77	8.1 ± 0.41	6.1 ± 0.21
+	7.9 ± 0.33	3.5 ± 0.35	8.5 ± 0.59	11.0 ± 0.71	8.4 ± 0.05	6.8 ± 0.22
Succinate
−	2.7 ± 0.51	3.8 ± 0.29	3.1 ± 0.16	6.8 ± 0.19	4.4 ± 0.32	0.0 ± 0.00
+	3.3 ± 0.23	3.7 ± 0.31	3.2 ± 0.20	7.8 ± 0.94	5.0 ± 0.14	0.0 ± 0.00
Lactate
−	0.4 ± 0.57	0.0 ± 0.00	0.1 ± 0.19	1.5 ± 0.46	0.0 ± 0.00	0.0 ± 0.00
+	0.0 ± 0.00	0.0 ± 0.00	0.2 ± 0.21	0.7 ± 0.92	0.0 ± 0.00	0.0 ± 0.00
Formate
−	0.2 ± 0.22	5.9 ± 0.22	1.7 ± 0.96	4.7 ± 0.34	0.5 ± 0.13	0.0 ± 0.00
+	0.2 ± 0.06	6.4 ± 0.59	2.0 ± 0.93	5.1 ± 0.02	0.9 ± 0.31	1.0 ± 0.15
Yield [g_pro/g_gluc]
−	0.09 ± 0.00	0.23 ± 0.01	0.09 ± 0.00	0.06 ± 0.00	0.07 ± 0.00	0.34 ± 0.00
+	0.10 ± 0.00	0.25 ± 0.01	0.11 ± 0.00	0.06 ± 0.01	0.08 ± 0.00	0.39 ± 0.01
Molar ratio [mol_pro/mol_suc)
−	1.2	2.2	1.1	0.3	0.6	–
+	1.1	2.4	1.2	0.3	0.6	–
Molar ratio [(mol_pro + mol_suc) /mol_ac]
−	0.7	3.7	0.8	0.9	0.8	2.1
+	0.9	3.7	0.8	0.9	0.9	2.0

Cells were grown in defined minimal medium with 15 mM glucose (DMMG), either with ( +) or without (−) 0.5 g/l yeast extract in 48-well plates with 0.5 ml culture volume under anoxic conditions (N₂/CO₂; 80/20; vol/vol). The cultures were incubated for 24 h (B. propionicifaciens for 48 h) at 30 °C (B. propionicifaciens) and 37 °C (all others). Samples for product formation were retrieved at the end and analysed via HPLC. Average values and standard deviation of three biological replicates are shown. B. ce., B. cellulosilyticus; B. gra., B. graminisolvens; B. int., B. intestinalis; B. luti, B.luti;B. xylan, B. xylanisolvens; B. pro., B. propionicifaciens

ISSN: 2731-3654