Fig. 2

Cultivation of Paenibacillus polymyxa with increased concentrations of nicotinic acid in microtiter plate. Moppa medium (specified in Table 2) without or with increased concentrations of all vitamins of group 1 or of nicotinic acid. Vitamin group (gr.) 1 is specified in Additional file 1: Table S3. nic.: nicotinic. Initial concentrations were: 54.2–56.3 g/L (a-d) and 51.8–53.1 g/L (e–h) maltose, 4.2–4.5 g/L (a-d) and 4.1–4.3 g/L (e–h) glucose, 3.3–3.4 g/L (a-d) and 3.2–3.6 g/L (e–h) citrate. a, e: Oxygen transfer rate (OTR), b, f: Final optical density (OD), total oxygen consumption (TOC) and pH, c, g: Final maltose, glucose and citrate concentration, d, h: Final acetoin, 2,3-butanediol and lactate concentration. a, b: For clarity, only every 10th measuring point over time is marked as a symbol. Mean values for OTR of at least three replicates with standard deviations as shadows are shown. b, f: TOC was determined based on OTR data of the replicates. Mean values for TOC of the replicates with standard deviations depicted as error bars are shown. b-h: For offline analysis, samples (wells) of the replicates of the OTR measurement were pooled at the end of the experiments. OD measurement of pooled samples was performed in triplicate and mean values with standard deviations depicted as error bars are shown. OD of pooled sample of the cultivation w/o nicotinic acid was measured in duplicate and the mean value without standard deviation is shown. pH and concentrations of sugars and metabolites were determined in a single measurement of pooled samples. c – h: d.l. means that concentrations of components were lower than the detection limit. Parameters in c – h were determined after 61 – 66 h. Cultivation conditions: temperature 33 °C, 48-round well plate, filling volume 0.8 mL, shaking frequency 1000 rpm, shaking diameter 3 mm, 0.1 M MES, initial pH 6.5