Biological science / 9. Biochemistry and Biophysics

Gorshunov Yu.V., Galkin O.Yu.

National Technical University of Ukraine “Kyiv Polytechnical Institute”, Ukraine; Ukrainian Research Institute of Alcohol and Food Biotechnology, Ukraine

GLUCOSE-FRUCTOSE SYRUP AS A FEEDSTOCK FOR ETHANOL PRODUCTION

Cereal crops (corn, rye and wheat) and sugar containing raw materials (sugar beet and sugar cane molasses) are the main kinds of feedstock for biotechnological production of ethanol in Ukraine and many other countries worldwide [1, 2]. Unfortunately, prices of conventional raw materials for ethanol biosynthesis have been showing a persistent trend for growing in recent times to cause an increase in the cost of ethanol and erosion of its competitiveness in the external market. Therefore, a diversification of feedstock basis by using less expensive new sources of carbohydrates is of interest for the Ukrainian alcohol industry at this time.

Feedstock for ethanol production should meet the following criteria: it should be cheap and storable and it should be rich in carbohydrates or starch that may be transformed into ethanol by using the available facilities and yeast vital activity.

Today, sugar-containing starch products (molasses and glucose and glucose-fructose syrups) are large tonnage products of food industry being in stable and consistently growing demand, therefore, an interest to the use of the aforementioned products in the biosynthesis of ethanol is growing significantly in Ukraine and worldwide. Such products are broadly used in the manufacture of alcohol-free beverages, fruit drinks, syrups and confectionery and in brewage [3, 4, 5].

Accounting for the aforementioned, glucose-fructose syrup (GFS) is a most promising feedstock for ethanol production on a commercial scale in Ukraine.

This work is aimed at a study of the composition and biotechnological properties of GFS in view of its suitability for alcohol digestion and optimisation of the media composition.

In this work, GFS-42 and the processes of alcohol fermentation of a wort prepared on the basis of GFS-42, and fermented wort have been studied.

Physical and chemical composition of GFS-42 received directly from TH “Krakhmaloproduct”, LLC, the manufacturer of GFS-24 under TU U 15.6-3216426-009:2005 Specifications, has been studied.

The results of the determination of the main characteristics of GFS-42 are summarised in the Table below.

Table - Characteristics of glucose-fructose syrup (GFS-42)

Characteristic	Value
Dry solids weight ratio (DS), %	70.4
Weight fraction of total fermentable sugar, %	68.02
рН, units	3.8
Acidity, сm^3 (0.1 N NаОН) /100 g DS	2.8
Weight fraction of sulphur dioxide, %	0.024
Weight fraction of total nitrogen, %	0.27
Weight fraction of phosphorus (on Р2О5 basis), %	0.0014

The above Table shows that the dry solids content, pH and weight fraction of total fermentable sugar of GFS-42 make this raw material suitable for alcohol fermentation. However, total nitrogen at the level of 0.27 % and, in particular, phosphorus at the level of 0.0014 % suggest that a wort obtained from GFS-42 will have insufficient nitrogen and phosphorus for the normal vital activity of yeasts and ethanol biosynthesis. Therefore, to provide sufficient quantity of nitrogen and phosphorus nutrients for yeast, it is recommended to supplement the mixture for GFS-42 preparation with additional sources of nitrogen and phosphorus. According to the standards adopted in the practice of alcohol fermentation, nutritional medium for yeast should be supplemented with diammonium phosphate (DAP) and urea.

The performed studies of the composition and biotechnological properties of GFS-42 confirm the suitability of such feedstock for alcohol fermentation.

Literature

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2. P.L. Shyian. Innovative technologies in the alcohol industry. Theory and practice / P.L. Shyian, V.V. Sosnytskyi, S.Т. Oliinychuk. – Kyiv: Askania Publishing House, 2009. – 424 p.

3. G.A. Kovalenko. Modern technologies of plant feedstock processing to form sugar-containing starch products (molasses, syrups) / G.A. Kovalenko, L.V. Perminova // Fundamental Studies (Russ.). – 2008. – No. 1. – P. 80-80.

4. Yu. Bondarenko. Influence of glucose-fructose syrup on the consumer properties of sugar articles / Yu. Bondarenko, V. Drobot // Baking and Confectionery Industries in Ukraine (Ukr.). - 2009. - No. 6. - P. 8-10.

5. Т.А. Ladur. Glucose-maltose syrups in brewage / Т.А. Ladur // Beer and Beverages (Ukr.). - 1997. - No. 4. - P. 8.