Metabolic flux analysis in Ashbya gossypii using 13C-labeled yeast extract: industrial riboflavin production under complex nutrient conditions

Table 3 Relative ¹³C enrichment of all seventeen carbon atoms of riboflavin produced by A. gossypii B2 from different ¹³C-labeled tracer substrates

C-atom	Chemical shift (ppm)	Corrected relative enrichment (%)
		Nat. lab. precursors	[¹³C] For		[¹³C₂] Gly	[U¹³C] YE	[¹³C₅] Glu
		0 h	0 h	48 h	0 h	32 h	0 h
2	155.5	0.0	3.7	11.6	0.0	16.2	1.1
4	159.9	0.0	0.0	0.0	0.0	12.1	1.8
4a	136.8	0.0	0.0	0.0	72.1	19.6	0.0
5a	134	0.0	0.0	0.0	0.0	4.2	1.9
6	130	0.0	0.0	0.0	0.0	4.5	2.3
7	137.1	0.0	0.0	0.0	0.0	3.0	1.8
7α	18.8	0.0	0.0	0.0	0.0	3.0	1.7
8	146	0.0	0.0	0.0	0.0	4.0	1.9
8α	20.8	0.0	0.0	0.0	0.0	4.0	2.6
9	117.4	0.0	0.0	0.0	0.0	3.1	0.7
9a	132.1	0.0	0.0	0.0	0.0	3.0	0.3
10a	150.8	0.0	0.0	0.0	71.6	19.7	0.0
1′	47.3	0.0	0.0	0.0	0.0	9.9	2.9
2′	68.8	0.0	0.0	0.0	0.0	8.7	4.1
3′	73.6	0.0	0.0	0.0	0.0	7.7	3.0
4′	72.8	0.0	0.0	0.0	0.0	8.1	3.9
5′	63.4	0.0	0.0	0.0	0.0	7.3	1.6

The labeling was analyzed by ¹³C NMR. The measurement data (uncorrected, Additional file 1: Table S6) were corrected values for naturally occurring isotopes and dilution through naturally labeled pre-culture medium. The time refers to the respective tracer addition. Data denote mean values of three independent replicates with a mean standard deviation of 8%
For, formate; Glu, glutamate; Gly, Glycine; Ser, serine; YE, yeast extract

ISSN: 1475-2859