Metabolism of Scenedesmus obliquus cultivated with raw plant substrates

• Published in: Frontiers in plant science Vol. 13; p. 992702
• Main Authors: Schambach, Jenna Y, Kruse, Colin P S, Kitin, Peter, Mays, Wittney, Hunt, Christopher G, Starkenburg, Shawn R, Barry, Amanda N
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Media SA 02.12.2022; Frontiers Media S.A
• Subjects: metabolism; mixotrophy; Plant Science; plant substrate; Scenedesmus; transcriptomics; transcriptomics; Scenedesmus; metabolism; plant substrate; mixotrophy
• ISSN: 1664-462X; 1664-462X
• DOI: 10.3389/fpls.2022.992702

The potential benefits of adding raw, non-food, lignocellulosic plant material as a carbon source for mixotrophic growth of microalgae have previously been demonstrated. This approach has advantages over using traditional carbon sources like glucose or acetate due to wide-spread plant biomass availability and substrate recalcitrance to bacterial contamination. Here, we report the overall growth characteristics and explore the metabolic patterns of cultured in the presence raw plant substrate. An initial screen of plant substrate candidates showed an increase in specific growth rate and biomass accumulation when was cultured in the presence of switchgrass or yard waste compared to media alone. We observed a near doubling of microalgal dry weight when was grown with 0.2% ( ) switchgrass under ambient CO . Scanning electron microscopy (SEM) of corn stem after cultivation exhibited substantial phloem degradation. Transcriptomic analyses of during mid- and late-log phase growth revealed a dynamic metabolic landscape within many KEGG pathways. Notably, differential expression was observed for several potential glycosyl hydrolases. We also investigated the influence of switchgrass on the growth of at 50 L volume in mini raceway ponds to determine the scalability of this approach.