Production of high titer of citric acid from inulin

Abstract

BackgroundCitric acid is considered as the most economically feasible product of microbiological production, therefore studies on cheap and renewable raw materials for its production are highly desirable. In this study citric acid was synthesized by genetically engineered strains of Yarrowia lipolytica from widely available, renewable polysaccharide – inulin. Hydrolysis of inulin by the Y. lipolytica strains was established by expressing the inulinase gene (INU1 gene; GenBank: X57202.1) with its native secretion signal sequence was amplified from genomic DNA from Kluyveromyces marxianus CBS6432. To ensure the maximum citric acid titer, the optimal cultivation strategy–repeated-batch culture was applied.ResultsThe strain Y. lipolytica AWG7 INU 8 secreted more than 200 g dm− 3 of citric acid during repeated-batch culture on inulin, with a productivity of 0.51 g dm− 3 h− 1 and a yield of 0.85 g g− 1.ConclusionsThe citric acid titer obtained in the proposed process is the highest value reported in the literature for Yarrowia yeast. The obtained results suggest that citric acid production from inulin by engineered Y. lipolytica may be a very promising technology for industrial citric acid production.

Engineering Yarrowia lipolytica for the Synthesis of Glutathione from Organic By-Products

“…This was maximal during the mid-exponential growth phase (after 14 h of growth, 300 U/mL) and then decreased to 125 U/mL at the end of the growth phase (after 22 h; data not shown). The inulinase activity of strain RIY389 was in the range obtained previously in yeasts, including Y. lipolytica [18,35].…”

“…Moreover, the hydrolysis of inulin into fructose monomers is less complex than starch pretreatments. The heterologous expression of inulinase-encoding gene confers yeast the ability to hydrolyze inulin and to metabolize the released fructose directly [18][19][20]. Recently, the direct fermentation of Jerusalem artichoke powder for the production of lactic acid by an engineered strain of Kluyveromyces marxianus has been reported [21].…”

An efficient method for production of kynurenic acid by Yarrowia lipolytica

“…All the extraction was carried out as described by Turski et al, 2015 coupled to a refractive index detector (Shodex, Ogimachi, Japan). The column was eluted with 25-mM trifluoroacetic acid at 65 C and a flow rate of 0.6 ml/min as described by Rakicka et al, 2019. 3 | RESULTS…”

Sugar Alcohols and Organic Acids Synthesis in Yarrowia lipolytica: Where Are We?

“…When the strain was grown in a 10-L bioreactor in the presence of extract of Jerusalem artichoke tubers (i.e., with a total sugar concentration of 84 g/L), CA titer reached 68.3 g/L with a yield of 0.91 g/g within 336 h [36]. With the strain Y. lipolytica AWG7 INU 8, overexpressing INU1 gene from K. marxianus CBS6432, a CA titer of 203 g/L was obtained by repeated batch culture; this corresponded to a productivity and yield of 0.51 g/(L•h) and 0.85 g/g, respectively [37]. In addition, sucrose was tested as a carbon source for CA production with Y. lipolytica strain A101-B56-5 overexpressing invertase (SUC2 gene from Saccharomyces cerevisiae).…”