ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Efficient utilization of inulin and glycerol as fermentation substrates in erythritol and citric acid production using Yarrowia lipolytica expressing inulinase

Magdalena Rakicka, Zbigniew Lazar, Anita Rywińska, and Waldemar Rymowicz

Department of Biotechnology and Food Microbiology, Wrocław University of Environmental and Life Sciences, Chełmońskiego St. 37, 51-630 Wroclaw, Poland

E-mail: magdalena.rakicka@up.wroc.pl

Abstract: Inulin and glycerol were used as substrates for efficient erythritol and citric acid production by newly engineered Yarrowia lipolytica strains. Hydrolysis of inulin by the Y. lipolytica Wratislavia K1 strain was established by expressing the Kluyveromyces marxianus INU1 gene. Erythritol was produced in two stages: inulin was used for biomass formation, followed by erythritol biosynthesis initiated by glycerol addition. The highest titer of erythritol obtained, 120.9 g L⁻¹ with the yield of 0.6 g g⁻¹, was produced by the K1 INU 6 strain. Moreover, the K1 INU 6 strain in fed-batch culture produced a high amount of citric acid: 105.2 g L⁻¹ after 235 h from 200 g L⁻¹ of inulin. Maximum activity of inulinase during this culture was 14000 U g⁻¹ of cell dry mass. The presented study proves the potential of new Y. lipolytica transformants for efficient erythritol and citric acid production from inexpensive raw materials such as inulin and glycerol.

Keywords: inulin – erythritol – citric acid – glycerol – Yarrowia lipolytica

Full paper is available at www.springerlink.com.

DOI: 10.1515/chempap-2016-0085

Chemical Papers 70 (11) 1452–1459 (2016)