Analysis of the ability to form 2-phenylethyl alcohol by Galactomyces geotrichum MK017

Abstract

The aim of the study was to evaluate the ability of Galactomyces geotrichum MK017 for the biosynthesis of 2-phenylethyl alcohol and optimization of the culture medium composition in order to increase the yield of the product. The culture of Galactomyces geotrichum MK017 strain was carried out in the laboratory scale. For isolation of volatiles Solid Phase Microextraction (SPME) has been used. The identification and quantification of aroma compounds produced by examined microflora was determined by gas chromatography and mass spectrometry (GC/MS) system. The results showed that the tested mould Galactomyces geotrichum MK017 shows the potential for the production of 2-phenylethyl alcohol, but also for the synthesis of phenylacetaldehyde, phenylacetic and phenyllactic acids. For the optimization of the 2phenylethyl alcohol production yield four different medium composition have been tested. The bioprocess of aroma compound production by tested microorganism was the most efficient on the medium composed of sucrose (80 g/l) and L-phenylalanine (21 g/l) and pH value of 5.0. Using this composition in a batch culture of 770 ml volume the highest concentration of 2-phenylethyl alcohol has been obtained-6 mg/l. At the same time amount of phenylacetaldehyde, phenylacetic acid and phenyllactic acidhas reached 2.2 mg/l, 10.66 mg/l and 32.3 mg/l respectively.

Galactomyces geotrichum – moulds from dairy products with high biotechnological potential

“…The most efficient production was obtained when the medium was composed of sucrose (80 g/l), L-phenylalanine (21 g/l) and when the pH value in the batch culture was 5.0. In this medium, the mould was also able to produce phenylacetaldehyde, as well as phenylacetic and phenyllactic acid (Grygier et al, 2015).…”

Analysis of the Ability to Produce Pleasant Aromas on Sour Whey and Buttermilk By-Products by Mold Galactomyces geotrichum: Identification of Key Odorants

“…Strain 32 was lyophilized to standardize inoculum concentration. Shake flask cultivations were carried out in four 300 mL Erlenmeyer flasks with 100 mL of base medium containing per liter (modified, based on Grygier et al [ 48 ]) 22.8 g of Na 2 HPO 4 ·2H 2 O, 10.3 g of citric acid, 0.5 g of MgCl 2 , and 0.17 g of yeast extract. The medium was sterilized, and then sucrose and L-phenylalanine were added to it at a concentration of 60 g/L and 21 g/L, respectively.…”

The Use of Sour and Sweet Whey in Producing Compositions with Pleasant Aromas Using the Mold Galactomyces geotrichum: Identification of Key Odorants

“…Galactomyces geotrichum is a mold that occurs naturally in dairy products, which, according to our recent studies, is responsible for the formation of rose-like aroma compounds, such as phenylacetaldehyde, 2-phenylethanol, and phenylacetic acid. , We have, moreover, noted that the concentration ratio of phenylacetaldehyde and 2-phenylethanol is unusually close to 1:1 in the fried cottage cheese we tested. Phenylacetaldehyde has a lower odor threshold (OT) than 2-phenylethanol in a range of food matrices (60 times lower in water, 10 times lower in oil, and 4 times lower in starch), ,− which is why its highest content in the produced aroma is desirable. , …”

“…This means that there is a need for relatively efficient and straightforward technologies that can produce volatile compounds of natural origin. Particular attention should be paid to biotechnological processes that do not suffer from the difficulties attendant on the extraction of aroma compounds from natural materials (including seasonality and effect of climate change on the acquisition of the raw materials), which can make use of industrial byproducts. ,− …”

“…Phenylacetaldehyde has a lower odor threshold (OT) than 2phenylethanol in a range of food matrices (60 times lower in water, 10 times lower in oil, and 4 times lower in starch), 7,9−11 which is why its highest content in the produced aroma is desirable. 6,7 Whey is a yellowish liquid obtained during cheese production by separating the curd. About 160 million tons of whey is produced globally each year.…”