Affiliation:
1. Department of Biotechnology and Food Microbiology, The Faculty of Biotechnology and Food Science, Wroclaw University of Environmental and Life Sciences, Chełmońskiego Str. 37, 51-630 Wrocław, Poland
Abstract
Citric acid and erythritol are obtained on an industrial scale using biotechnological methods. Due to the growing market demand for these products, research is underway to improve the process economics by introducing new microorganisms, in particular of the species Yarrowia lipolytica. The aim of this study was to evaluate transformants of Y. lipolytica for growth and ability to overproduce citric acids and erythritol from glycerol. The transformants were constructed by overexpressing glycerol kinase, methylcitrate synthase and mitochondrial succinate-fumarate transporter in the mutant Wratislavia 1.31. Next, strains were assessed for biosynthesis of citrate (pH 5.5; nitrogen limitation) and erythritol (pH 3.0; high osmotic pressure) from glycerol. Regardless of culture conditions strains, 1.31.GUT1/6 and 1.31.GUT1/6.CIT1/3 exhibited high rates of substrate utilization. Under conditions favoring citrate biosynthesis, both strains produced several percent more citrates, accompanied by higher erythritol production compared to the parental strain. During erythritol biosynthesis, the strain 1.31.GUT1/6.CIT1/3.E34672g obtained as a result of co-expression of all three genes stood out, producing 84.0 g/L of erythritol with yield and productivity of 0.54 g/g and 0.72 g/Lh, respectively, which places it in the group of the highest-ranked producers of erythritol among Y. lipolytica species.
Funder
Wrocław University of Environmental and Life Sciences
Subject
Inorganic Chemistry,Organic Chemistry,Physical and Theoretical Chemistry,Computer Science Applications,Spectroscopy,Molecular Biology,General Medicine,Catalysis