Studies on the Attached Cultivation of Filamentous Oleaginous Microalga Tribonema minus

Abstract

Attached cultivation is a promising method for microalgal biomass production. Filamentous oleaginous microalga Tribonema minus (hereafter T. minus ) has shown a remarkable potential for biofuel production in terms of its high lipid content. However, the strain has only been cultivated in suspended cultivation systems including open pond and closed photobioreactors. Here, we attempted to study the attached cultivation of T. minus , which might be helpful for its scale-up cultivation and industrial applications. As the results, the optimal conditions for T. minus growth in the attached biofilm are 200 μmol photons m −2 s −1 of light intensity and 5% of CO 2 , and the maximum biomass density of 223 g m −2 has been achieved under the light intensity. The non-woven fabric as substratum was found as the best substratum in thin layer attached bioreactor, on which the average biomass productivity of T. minus is about (9.73 ± 2.19) g m −2 d −1 . Furthermore, two attached bioreactor systems, rotary drum and rotation disc, were designed following the light dilution strategy and introduced into T. minus cultivation. The highest footprint areal biomass productivity of these two systems is 33 and 47.1 g m −2 d −1 , respectively, much higher than that in suspended cultivation system. The results shows that T. minus can be cultured with attached cultivation method to improve its biomass productivity.