Monoraphidium sp. IBASU-A 574 (Selenastraceae, Chlorophyta) - a promising producer of biomass for bioenergy

Abstract

he present studies were carried out to evaluate a potential biofuel application of the native strain Monoraphidium sp. IBASU-A 574 (Selenastraceae, Chlorophyta) adapted to the temperate zone climatic conditions. This strain was isolated from a small freshwater lake situated in Kyiv-city (Ukraine) by the reached culture method for obtaining desired strains of different species with high growth rate. It was identified based on its morphological characterization under light microscopy and 18S rRNA sequence analysis. Its culture’s growth, kinetic characteristics (specific growth rate and productivity) and biological peculiarities of the investigated strain were studied in comparison with the well-known biomass producer Chlorella vulgaris Beijer. CALU 157 under the same autotrophic cultivating conditions with using the modified Tamiya medium. It was established an active growth of Monoraphidium sp. IBASU-A 574 which was practically equal to the well-known producer and characterized by following parameters: a maximum cell density of 248 ∙ 10-6 cells ∙ mL-1, the specific growth rate of 1.4 days-1 and productivity of 72.5 ∙ 10-6 cells ∙ mL-1 ∙ days-1. The results of gas-liquid chromatography analysis showed that a fatty acid profile of this microalga included a complex of palmitic (C16: 0), oleic (C18: 1), linoleic (C18: 2) and linolenic (C18: 3) major fatty acids with suitable proportion for developing biodiesel feedstocks. Moreover, there was considerable variation in formation of its fatty acid composition depending on the stage of growth, that confirmed the necessity for such studies to determine both optimal time for growing algae and gaing maximum yield of target products. Thus, Monoraphidium sp. IBASU-A 574 was found to be the promising producer of biomass for bioenergetic industry due to obtained data of its growth characteristics and suitable fatty acid profile of lipids.