The applicability of the Beer-Lambert-Bouguer equation in determination microalgal biomass by culture optical density is discussed. Analysis of published data showed that due to the high heterogeneity of microalgae culture, as well as microalgae culture of high density, there is considerable deviation from a linear equation between optical density and microalgae biomass. A mathematical model describing the dependence of optical density from microalgae biomass is proposed. The model is based on the assumption that each cell absorbs the same amount of light energy, is not changed in size and has a fixed surface area. It is shown that experimental dependences of transmittance from the microalgae biomass can be described by the obtained equation with high accuracy (R2 = 0.99). Unlike the equations of the Beer-Lambert-Bouguer, the optical density from microalgae biomass is nonlinear.
Beer-Lambert-Bouguer law, the light intensity, the extinction coefficient
1. Chen Y., Vaidyanathan S. A simple, reproducible and sensitive spectrophotometric method to estimate microalgal lipids. Anal. Chim. Acta, 2012, vol. 724, pp. 67-72.
2. Collos Y., Mornet F., Sciandra A., Waser N., Larson A., Harrison P.J. An optical method for the rapid measurement of micromolar concentrations of nitrate in marine phytoplankton cultures. J. Appl. Phycol., 1999, vol. 11, pp. 179-184.
3. Sid'ko F.Ya., Eroshin N.S. Opredelenie koncentracii pigmentov i chisla kletok vo vzvesi vodorosley na fotoelektrokolorimetre FEKN-57. Upravlyaemoe kul'tivirovanie mikrovodorosley, M.: Nauka, 1964, c. 38-42. [Sydko F.Ya., Eroshin N.S. The determination of pigments concentration and cell numbers in algae suspensions on photoelectrocolorimeter FECN-57. Upravlyaemoe kultivirovanie mikrovodorosley. M.: Nauka, 1964, pp. 38-42. (In Russ.)]
4. Gevorgiz R.G., Alisievich A.V., Shmatok M.G. Ocenka biomassy Spirulina platensis (Nordst.) Geitl. po opticheskoy plotnosti kul'tury. Ekologiya morya, 2005, vyp. 70, s. 96-106. [Gevorgiz R.G., Alisevich A.V., Shmatok M.G. Estimation of Spirulina platensis (Nordst.) Geitl. biomass by optical density. Ecologia morya, 2005, vol. 70, pp. 96-106. (In Russ.)]
5. Furyaev E.A. Mikrospektrofotometricheskie harakteristiki kletok vodorosley v razlichnyh usloviyah kul'tivirovaniya. avtoref. kand. dis., Krasnoyarsk, 1979, 23 c. [Furyaev E.A. Microspectrophotometric characteristics microalgae cells in different culture condition. avtoref. kand. dis., Krasnoyarsk, 1979, 23 p. (In Russ.)]
