Fig. 3
Effect of different yeast extracts on microaerobic A. vinelandii ATCC9046 cultivations. Cultivations were conducted in modified Burk’s medium with 3 g/L yeast extract from different manufacturers. Standard deviations are given for n ≥ 3, represented by a shadow or error bars and are in some cases so small that they are not well recognizable. Significant differences to the reference (Roth Batch 1) are marked with asterisks, corresponding to the significance level (* for 0.01 < p < 0.05, ** for 0.001 < p < 0.01 and *** for p < 0.001). A–D: For clarity, only every fifth measuring point of the OTR curves is shown. The number of replicates is given with n; if n = 2, the mean value is shown and the shadow depicts the difference between the two replicates. The OTR curves for each replicate of cultivations with Roth Batch 1 and AppliChem are shown in Additional file 1: Fig. S1A, B, respectively. The horizontal dashed line depicts the OTR value of 2 mmol/L/h for an easier comparison of the nominal cultivation time. E–H: All given values are mean values, calculated from the following number of replicates: cell dry weight, n ≥ 8; alginate dry weight, n ≥ 6; mean molecular weight, n ≥ 5; broth viscosity, n ≥ 4. The flow curves and the acetylation degree are provided in Additional file 1: Fig. S3. Cultivation conditions: 250 mL shake flasks, initial pH = 7.2, filling volume VL = 50 mL, temperature T = 29 °C, shaking frequency n = 165 rpm, shaking diameter d0 = 50 mm