ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Estimating protein quantities from microalgae: protein per biomass percentage, spectroscopic concentration, and lectin content

Diego de Carvalho Carneiro, Mariane Mascarenhas Oliveira, and Suzana Telles da Cunha Lima

Universidade Federal da Bahia, Salvador, Brazil

E-mail: diegoccarneiro@gmail.com

Abstract: Protein quantifications can be essential steps in the screening of microalgae strains. The protein per biomass percentage of seven species of Chlorophyceae microalgae was estimated by a procedure that includes a protein precipitation step for removal of interfering substances. Ankistrodesmus fusiformis, Coelastrum microporum and Scenedesmus obliquus presented the highest protein content (22%, 21%, and 25%, respectively), whereas Chlamydocapsa bacillus presented the lowest protein per biomass ratio (11%). Specific values of percent extinction coefficients (E1%) for each strain was used as a strategy for rapid estimations of total protein concentrations from microalgae by absorbance readings at 280 nm. The species found with the highest lectin contents were Kirchneriella lunaris, Pseudokirchneriella subcapitata and C. bacillus, since they rendered the highest specific hemagglutinating activity (SHA) values for their total protein precipitates (5.2, 3.5, and 2.3, respectively), which was defined as the ratio between the hemagglutinating activity titer and the logarithm of its total protein concentration in μg/mL. Because the titer is indirectly associated to the concentration of lectins in a sample before the serial dilution, the SHA is more convenient for screening of different species, as it also includes the protein concentration of the titer.

Keywords: Screening ; Protein content ; Hemagglutinating activity ; Percent extinction coefficient 

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-019-00807-9

Chemical Papers 73 (10) 2535–2540 (2019)