Molecular analysis of sugar transporters and glycolysis pathways in Ettlia sp. under heterotrophy using fructose and glucose

Abstract

Fructophilic behavior in microalgae is a rare trait that could benefit biorefineries by enabling substitution of carbon source with fructose, and our previous study identified that Ettlia sp. prefers fructose relative to glucose. In this study, by analyzing the transcription levels of genes related to sugar transport and the glycolysis pathway, the fructose utilization of Ettlia sp. was investigated. In a fructose‐containing medium, the expression levels of fructokinase (EttFRK3) and glucokinase (EttGCK1 and EttGCK2) genes were significantly upregulated in heterotrophic cultivation of Ettlia sp. under fructose supplementation conditions. Further, a sugar transporter (EttSTF11) was significantly upregulated by 3.2‐fold in 1 day, and this increase was analogous to the specific growth rate exhibited by the species. Subsequent cultivation tests with multi‐sugar sources also showed a significant upregulation of EttSTF11 relative to other treatments without fructose. A phylogenetic tree derived from the analysis of different transporters of interest identified that EttSTF11 was adjacent to reference fructose transporters with a high bootstrap value of 71. Given that the transmembrane domains of EttSTF11 were analogous to those of reference fructose transporter genes, EttSTF11 appeared to play a critical role in fructose consumption and metabolism in Ettlia sp.

Effect of DACH-K2CO3 Mixed Absorbent on the Performance of a CO2 Absorption and Microalgae Conversion (CAMC) System

“…The third category was enriched in the transport of glucose metabolism, such as “hexose transmembrane transport,” etc. Glucose metabolism is an important process of energy metabolism and substance metabolism in cells, including the synthesis, degradation, and transport of sugar …”

“…Glucose metabolism is an important process of energy metabolism and substance metabolism in cells, including the synthesis, degradation, and transport of sugar. 45 To further explore the functions of DEGs in metabolic pathways, KEGG pathway enrichment analysis was conducted on DEGs. Figure 5c lists the top 30 altered enriched pathways changed by KEGG annotation.…”

Recent advances and fundamentals of microalgae cultivation technology

“…[85] In the H. pluvialis, the pH steady cultivation is accompanied by the increase of biomass accumulation, nitrate consumption and carbon fixation due to increased Ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCo) activity. [86] In addition to CO 2 , carbon can also be supplied as different organic molecules, which typically enhance the microalgae growth, [142,153,154] It was recently reported that a combination of acetate and pyruvate enhanced the Haematococcus lacustris growth twice in mixotrophic in comparison to phototrophic conditions. [153]…”

“…In addition to CO 2 , carbon can also be supplied as different organic molecules, which typically enhance the microalgae growth, [ 142,153,154 ] It was recently reported that a combination of acetate and pyruvate enhanced the Haematococcus lacustris growth twice in mixotrophic in comparison to phototrophic conditions. [ 153 ]…”