RU2195494C2 - Method of l-(+)-lactic acid preparing - Google Patents

Abstract

FIELD: biotechnology, microbiology. SUBSTANCE: method involves fermentation of Jerusalem artichoke powder of ground tubers with microorganism Streptococcus bovis. Method ensures to simplify and decrease cost of the process of preparing L-(+)-lactic acid and to retain its properties and physical-chemical indices. EFFECT: improved method of preparing. 2 ex

Description

 The invention relates to the field of microbiological industry, and in particular to a method for the production of lactic acid from inulin-containing raw materials.

 A known method of producing lactic acid on various carbohydrate-containing raw materials (Smirnov VA Food acids / M. Light and food industry, 1983, 264 C.). According to this method, lactic acid is obtained by fermentation of sources containing fermentable sugars (raw sugar, molasses, beet molasses) using bacterial strains Lactobacillus delbrueckii.

 The disadvantage of this production method is the relatively high cost of the substrates and, as a consequence, the high cost of the final product.

 There is also a method of producing lactic acid from agricultural waste (Galkina G.V., Illarionova V.I., Gorbatova E.V. Possibility of producing food acids from waste starch raw materials. / Food Industry, Inf. Sb. AgroNIITEIPP, 1993, no. 2, pp. 18-20) using strains of L. delbrueckii. The known method is the closest to the claimed technical essence and the achieved result and is taken as a prototype.

 The disadvantage of this method is the need for preliminary hydrolysis of plant materials.

 The purpose of the invention is the simplification and cheapening of the method for producing lactic acid while maintaining its properties and physico-chemical parameters.

 The essence of the proposed method lies in the fact that lactic acid is obtained by fermentation of milled tubers of Jerusalem artichoke Streptococcus bovis.

The proposed method allows you to:
1) to simplify and reduce the cost of the production process by eliminating the expensive stage of pre-fermentation processing and hydrolysis of the substrate;
2) reduce the cost of the resulting lactic acid.

 It is proposed to use representatives of the Streptococcus genus, in particular the Streptococcus bovis species, capable of hydrolyzing the inulin contained in the substrate to fermentable sugars and simultaneously produce L (+) lactic acid as producers for the production of lactic acid from Jerusalem artichoke. The use of such a producer eliminates the stage of pre-fermentation hydrolysis of inulin and leads to a reduction in both the cost of the product and the duration of the process. The low nutritional needs of S. bovis, which distinguishes this species from other lactic acid bacteria, make it possible to use various inulin-containing raw materials for lactic acid fermentation, without the need for additional growth factors. In contrast to the processes currently in use, where fractional dosed feed of the substrate is used to avoid catabolite repression, in this method the entire substrate can be supplied at the beginning, which simplifies the process.

 Example 1

 a) getting the starting culture.

From 1 g of starch, 0.5 g of peptone, 0.5 g of yeast extract, 0.02 g of ammonium nitrate and 50 ml of water, a liquid nutrient medium was prepared, which was sterilized at 121 ^° C for 30 minutes. After cooling, the medium was inoculated strain Streptococcus bovis ATCC-49133. The culture was grown for 24 hours at 37 ^{° C.} and a pH of 6.5;
b) sterilization of the substrate.

150 g of dry Jerusalem artichoke powder was poured into 400 ml of 0.04-0.1 N. sulfuric acid and kept for 4-6 hours, after aging, neutralized boiled chalk milk with a CaCO ₃ content _of 40 g was added to neutralize, then the volume of the fermentation medium was adjusted to 800 ml with sterile water;
c) obtaining L (+) lactic acid.

In a 1 liter fermenter equipped with a stirrer, a disinfected medium was poured, after which the starting one was seeded. Stirring periodically, it was cultured for 96 hours at t = 37 ^o C. After this time, almost all sugars were utilized, and the concentration of lactic acid reached 74 g / l.

 Example 2

 a) getting the starting culture.

From 1 g of starch, 0.5 g of peptone, 0.5 g of yeast extract, 0.02 g of ammonium nitrate and 50 ml of water, a liquid nutrient medium was prepared, which was sterilized at 121 ^° C for 30 minutes. After cooling, the medium was inoculated microorganism Streptococcus bovis TMC-235. The culture was grown for 24 hours at 37 ^{° C.} and a pH of 6.5;
b) sterilization of the substrate.

250 g of ground tubers of Jerusalem artichoke were poured into 600 ml of tap water and 100 g of chalk and sterilized for 30 min at a temperature of 121 ^o C.

A sterilized medium was poured into a 1-liter fermenter equipped with a stirrer, and after cooling to 37 ^° C, the starting culture was seeded. Stirring periodically, it was cultured for 96 hours at t = 37 ^o C. After this time, almost all sugars were utilized, and the concentration of lactic acid reached 85 g / l.

 Thus, the proposed technical solution is new, has an inventive step, is industrially applicable and allows to simplify and reduce the cost of the method of producing lactic acid while maintaining its properties and physico-chemical parameters.

Claims (1)

 A method of producing L (+) lactic acid by fermentation of an inulin-containing raw material by a microorganism that causes lactic acid fermentation, characterized in that the powder or ground Jerusalem artichoke tubers are used as raw material, and Streptococcus bovis is used as a microorganism.