Transcriptome Mechanism of Utilizing Corn Steep Liquor as the Sole Nitrogen Resource for Lipid and DHA Biosynthesis in Marine Oleaginous Protist Aurantiochytrium sp.

Abstract

In the current study, corn steep liquor (CSL) is evaluated as an ideal raw agro-material for efficient lipid and docosahexaenoic acid DHA production by Aurantiochytrium sp. Low CSL level in medium (nitrogen deficiency) stimulated the biosynthesis of lipids and DHA while inhibiting cellular growth. The transcriptomic profiles of the Aurantiochytrium sp. cells are analyzed and compared when cultured under high (H group), normal (N group), and low (L group) levels of CSL in the medium. The discriminated transcriptomic profiles from the three groups indicates that changes in CSL level in medium result in a global change in transcriptome of Aurantiochytrium sp. The overall de novo assembly of cDNA sequence data generated 61,163 unigenes, and 18,129 of them were annotated in at least one database. A total of 5105 differently expressed (DE) genes were found in the N group versus the H group, with 2218 downregulated and 2887 upregulated. A total of 3625 DE genes were found in the N group versus the L group, with 1904 downregulated and 1721 upregulated. The analysis and categorization of the DE genes indicates that the regulation mechanism of CSL involved in the perception and transduction of the limited nitrogen signal, the interactions between the transcription factors (TFs) and multiple downstream genes, and the variations in downstream genes and metabolites, in sequence, are illuminated for the first time in the current study.

Lipid Production of Schizochytrium sp. HBW10 Isolated from Coastal Waters of Northern China Cultivated in Food Waste Hydrolysate

“…For S. sp. HBW10, the relative content of PUFAs in the total fatty acids was obviously less than in the thraustochytrid strains previously isolated from the tropical and subtropical areas of China as we reported previously, not to mention the cold habitats [6]. Thraustochytrid strains isolated from a low-temperature environment had been speculated to produce more PUFAs, which had been proved by our previous study [27], as well as those reported elsewhere [41][42][43].…”

“…This might be explained by the phytoplankton bloom which triggered periodic explosive growth of thraustochytrids, a kind of saprophytic protist. Antibiotics were added into the isolation and purification medium for bacteria and fungi elimination as mentioned previously [6]. Notably, more antibacterial drugs were needed for strain isolation of thraustochytrids in temperate habitats than that in tropical waters.…”

“…Because it contains amounts of organic and inorganic nutrients, food waste has been widely used as feedstock for microbial fermentation in lipid, hydrogen, and methane production [1][2][3][4][5]. In addition, functional chemicals, such as polyunsaturated fatty acids [6], squalene [7] and carotenoids [8], as well as polymer degradable biomaterials such as biobased polyhydroxybutyrate [9], succinic acid [10], plasticizers and surfactants [11], could be synthesized through microbial conversion utilizing food waste. Thus, food waste could be an effective and sustainable substrate for biochemical production, and its bioconversion facilitates environmental protection and alleviates the energy crisis.…”

Current advances for omics-guided process optimization of microbial manufacturing

“…Wang et al found that a low-concentration corn steep liquor solution facilitated the docosahexaenoic acid production of thraustochytrids , and high-concentration of corn steep liquor led to increased biomass. The transcriptomic analysis was performed at high, normal, and low levels of corn steep liquor in culture medium to elucidate the low level of corn steep liquor affecting the perception and transduction of a limited-nitrogen signal and interactions between the transcription factors at the transcriptional level for improving lipid and docosahexaenoic acid productivity, providing new directions for subsequent optimization of production (Wang et al 2019 ). The contents of total lipids and exopolysaccharides in P. purpureum were significantly improved under nitrogen stress.…”

Metagenomic Analysis of Bacterial, Archaeal and Fungal Diversity in Two-Stage Anaerobic Biodegradation for Production of Hydrogen and Methane from Corn Steep Liquor

“…Acetogenesis and methanogenesis are slower processes that produce methane [ 9 , 10 ]. Anaerobic digestion has appeared to be one of the most reliable processes with a broad future potential [ 11 ]. Anaerobic digestion comprises sequential processes accomplished by microorganisms that break down biodegradable material in the absence of oxygen [ 12 ].…”