Spectrometric Characteristic of Superficial <i>Chlorella</i> Sp. Grown in Photo-Bioreactor under Different Flow Rates

Abstract

In this study, photo-bioreactor designed with 4 L of volume to cultivate Chlorella sp. was conducted for comparing the differences of biomass increase among three gas flow rates. All experiments were controlled at light reaction of 12 hrs. with 1,700 lux. The organic fluorescence of algae, expressed in excitation emission fluorescent matrix (EEFM), was obtained from algal solution deducted from EEFM of the filtrate obtained from the filtration of algal solution using 0.2 μm membrane filter. Also, the surface charge and functional group for Chlorella sp. were respectively measured by zeta meter and Fourier transform infrared spectroscopy (FTIR). Biomass was measured by absorbance wavelength of 683 nm or dried biomass. Current results reveal that high flow rate produced more biomass than low flow rate did. Regarding to the fluorescent characteristic derived from Chlorella sp., two peaks were appeared in both wavelengths of excitation and Emission (EX/EM) respectively located at 280/330 nm (protein-like) and 440-480/680 nm (pigment). For the variation of autofluorescent intensities during algal incubation, algal image captured by epofluorescent microscope equipped with CCD (Charge-Coupled Device) could be further dealt using image software, showing that there were divergences of fluorescent intensities derived from varied amount of protein-like substance or pigment. Functional group of Chlorella sp. analyzed by FTIR, hydroxyl, peptidic bond, carboxylic acids and polysaccharide were existed with variations of transmittance (%) while gas flow rate was changed.