Liquid Anaerobic Digestate as a Source of Nutrients for Lipid and Fatty Acid Accumulation by Auxenochlorella Protothecoides

Abstract

In recent years, there has been growing interest in the biomass of unicellular algae as a source of valuable metabolites. The main limitations in the commercial application of microbial biomass are associated with the costs of production thereof. Maize silage is one of the main substrates used in biogas plants in Europe. The effects of sterilized agricultural liquid digestate (LD) from methane fermentation of maize silage on the growth rates, macro and micronutrient removal efficiency, lipid content, and fatty acid profile in Auxenochlorella protothecoides were investigated. The results indicate that A. prothecoides can proliferate and accumulate lipids with simultaneous reduction of nutrients in the 1:20 diluted liquid digestate. The rate of nitrogen and phosphorus removal from the liquid digestate was 79.45% and 78.4%, respectively. Cells growing in diluted liquid digestate exhibited the maximum lipid content, i.e., 44.65%. The fatty acid profile of A. prothecoides shows a decrease in the content of linolenic acid by 20.87% and an increase in oleic acid by 32.16% in the LD, compared with the control. The liquid digestate changed the content of monounsaturated fatty acids and polyunsaturated fatty acids. The cells of A. protothecoides growing in the liquid digestate were characterized by lower PUFA content and higher MUFA levels.

Cultivation of microalgae on liquid anaerobic digestate for depollution, biofuels and cosmetics: a review

“…Moreover, Auxenochlorella protothecoides cultures removed phosphate by 30%. Auxenochlorella protothecoides were used for nutrient removal from diluted (1:2) agricultural liquid digestate resulting in nitrogen and phosphorus removal of 79.45% and 78.4%, respectively (Krzemińska et al 2019). Scenedesmus obliquus (FACHB-31) cultivation in diluted piggery liquid anaerobic digestate was investigated by (Xu et al 2015).…”

Performance of Brewery Digestate as a Potential Water Substitute in Concrete Applications

“…The organics presence, in volatile solids (VS), shows that about 7.2% (w./w). is degradable matter, with values mostly in line with other brewery digestate [29]. At the end of the digestion period (~28 days), the degradation resulted in the production of biogas, with an average methane yield of 44.0 CH 4 mL/g VS .…”

A Review on Synchronous Microalgal Lipid Enhancement and Wastewater Treatment

“…The post-fermentation wastewater comprises a high content of nitrogen and phosphorus, significant amounts of dissolved carbon dioxide, and low organics. A. prothecoides when cultivated in post-fermentation wastewater reported 79.45% nitrogen removal, 78.4% phosphorus removal, and the maximum lipid content of 44.65% [40].…”