A fast method for the quantification of methylamine in fermentation broths by gas chromatography

The objective of this study was to develop a method for the quantitative analysis of the methylamine concentration in fermentation broths of Hyphomicrobium zavarzinii ZV 580 cultures. For this purpose an established method for the quantification of free amino acids in such matrices was adapted and validated. The detection limit was 10 μM, the calibration curve showed good linearity (R2 = 0.9998) in the concentration range between 0.1 and 8 mM. The standard deviation of the injection-to-injection reproducibility (n = 10) of the retention coefficient was <1%, that of the peak area <5%. In case of the sample-to-sample reproducibility (n = 8), the standard deviation was <5% for the retention coefficient and <10% for the peak area. The validated method was successfully applied for monitoring a fed-batch bioprocess (starting volume: 8 L, initial methylamine hydrochloride concentration: 10 mM) producing a dye-linked formaldehyde dehydrogenase in H. zavarzinii ZV 580.