Production of Bioactive Compounds by Food Associated Galactomyces geotrichum 38, as Determined by Proteome Analysis

Abstract

Fried cottage cheese is a dairy product, popular in some parts of Poland. Proteomic analysis of a culture of the mold Galactomyces geotrichum 38 isolated from fried cottage cheese was performed using UHPLC/MS. From the proteins identified, we selected those involved in the biosynthesis of bioactive compounds and those useful in industry. In the G. geotrichum 38 culture, the production quantities of vitamin B₂ (224 μg/L), ergosterol (54.63 mg/kg), and trehalose (0.91 g/L) were determined by HPLC. The identified proteins were also used to prepare a hypothetical fatty acid biosynthesis pathway, and the percentage of individual sphingolipids in the culture was determined. Sphingolipids are also bioactive compounds. During culturing of G. geotrichum 38, the percentage of three sphingolipids increased. The last step of the research was to prepare a model of fried cottage cheese. The mold G. geotrichum 38, used in the process of ripening fried cottage cheese, synthesized vitamin B₂ and erogsterol, which influenced the nutritional value of the product.

Keywords: G. geotrichum; ergosterol; protein analysis; trehalose; vitamin B2.

Figure 1

Pathway of fatty acid transformation in G. geotrichum. hexokinase (HK, EC2.7.1.1), transketolase (TKT, EC2.2.1.1), transaldolase (TALDO, EC2.2.1.2), phosphofructokinase (PFK, EC2.7.1.11), glyceraldehyde 3-phosphate dehydrogenase (GAPDH, EC1.2.1.12), phosphoglycerate kinase (PGK, EC2.7.2.3), triose-phosphate isomerase (TPI, EC5.3.1.1), enolase (ENO, EC4.2.1.11), pyruvate kinase (PK, EC2.7.1.40), malate dehydrogenase (MDH, EC1.1.1.37), citrate synthase (CS, EC2.3.3.1), aconitase (ACO, EC4.2.1.3), isocitrate dehydrogenase (IDH. EC1.1.1.41 and EC1.1.1.42), glutamate dehydrogenase (GLUD, EC1.4.1.2 and EC1.4.1.3), phosphoenolpyruvate carboxykinase (PCK, and EC4.1.1.32 EC4.1.1.49), succinate dehydrogenase (SDH EC1.3.5.1), alcohol dehydrogenase (ADH, EC1.1.1.2), phosphoglycerate kinase (GLYCTK, EC2.7.1.31), aldehyde dehydrogenase (ALDH, EC1.2.1.3), isocitrate lyase (ICL, EC4.1.3.1), methionine synthase (MS, EC2.1.1.13), and n.- enzymes, whose content in the sample cannot be identified the method used (own work on the basis of Wang et al. [63]).

Figure 2

Trehalose content of G. geotrichum 38 culture.