Optical monitoring of the development of Dunaliella salina microalgae cultures
Daniil A. Puzanov1, Vladimir A. Bogatyrev1, Lev A. Dykman1, Nikolai G. Khlebtsov1
1.Institute of Biochemistry and Physiology of Plants and Microorganisms, Saratov Scientific Centre of the Russian Academy of Sciences (IBPPM RAS), Saratov, Russia
Abstract
The salt-water microalga Dunaliella salina is a promising object for biotechnological production, as it is an important source of antioxidant β-carotene. The issues of cultivation with high yield of the target product to a sufficiently large extent have not yet been solved. Increased production of secondary carotenoids (carotenogenesis) occurs in microalgae populations as a defence response to various stressors, the most important of which are increased salinity, increased light radiation, nitrogen nutrition deficiency, etc. The method of operative tracking of secondary carotenoids (carotenogenesis) has been developed.
A method of operative monitoring of the dynamics of abundance and changes in pigment composition in the culture of microalgae Dunaliella salina under the influence of various stressors was developed.
The method is based on spectrophotometric (SP) and digital photocolorimetric (DPC) analysis of light absorption spectra of living suspensions. The SP method was used to quantify the content of chlorophylls a and b as well as carotenoids. The basis of DPC assessment is the analysis of a time series of images (in transmitted light) of live microalgae suspensions in the additive RGB colour model. It is shown that the ratio of colours correlates to a high degree with the content of the determined main plant pigments - chlorophylls and carotenoids - and with the spectrophotometric measurements of live suspensions. Such colourometric monitoring of microalgae growth and development allows rapid, remote and non-destructive analysis of large arrays of samples for changes in the content of the main plant pigments.
Cell counting in a microscopic counting chamber and spectroscopy of dimethyl sulfoxide extracts of microalgae were used as comparison methods. As a result, the data of both methods correlate well with each other and with the data of the comparison methods, and also allow to construct growth curves and solve multi-parametric problems on optimisation of microalgae cultivation.
Speaker
Daniil Puzanov
Institute of Biochemistry and Physiology of Plants and Microorganisms, Saratov Scientific Centre of the Russian Academy of Sciences (IBPPM RAS)
Russia
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