Bradford method for microcystis biomass protein quantification

Introduction It is known, that microalgae are considered a viable source of protein and some of the species of microalgae contain similar protein levels as meat, eggs, soybeans and milk [1]. Aim The aim of the study – to determine the quantity of protein extracted from cyanobacteria biomass collected in Lake Simnas using Bradford test. Methods Cyanobacteria scum biomass from Lake Simnas (Alytus district) containing 84% of Microcystis and 12% of Dolichospermum species was received from the Nature Research Centre, Laboratory of Algology and Microbial Ecology. Wet weight of cyanobacteria biomass was poured into 15 mL test-tubes. Extraction was carried out by ultrasound sonication (3 times × 1min). Biomass homogenisation followed by pH adjustment to 13 with 1.0 M NaOH solution. The sample was cooled and centrifuged. Precipitate was discharged and supernatant was used in further experiments. Proteins were precipitated by TCA/Acetone, ice cold (-20 ºC) 13.3 % TCA solution in acetone, with 0.2 % of β mercaptoethanol (β-ME). Sample was incubated in -20 °C for 18 h. After incubation, sample was centrifuged and supernatant poured out. Precipitated proteins were washed with acetone and 0.2% β-ME. Washing was repeated 2 times. Washed protein pellets were resuspended in PBS buffer, pH 7.4. Bradford assay was used for protein quantification [2]. 595 nm wavelength absorption was measured with spectrophotometer [3]. Research results were statistically processed by using MS Excel software....[...].