RU2022009C1 - Method of preparing of nutrient substrate for food yeast growing - Google Patents

Abstract

FIELD: microbiological industry. SUBSTANCE: method involves alkaline hydrolysis of protein-containing waste, acid hydrolysis of plant raw, refining of acid hydrolysate, its neutralization with alkaline hydrolysate of protein-containing waste, separation of suspended particles, cooling and addition of nutrient salts to the prepared neutralisate. Hydrolysis of protein-containing waste with concentration 1-8 g/l is acrried out with 15-20% aqueous ammonia solution at -30-+80 C for 3-60 min. Active silt of refining units, slime residues of fermenting or yeast-growing tanks are used as a source of protein-containing waste. EFFECT: improved method of nutrient substrate preparing. 2 cl

Description

 The invention relates to the microbiological industry, in particular to a method for the preparation of hydrolysates for growing feed yeast.

A known method of preparing substrates for growing fodder yeast, including hydrolysis of wood raw materials, neutralizing excess acidity, separating suspended solids, diluting the substrate with an aqueous extract of an active or treatment plant, cooling and subsequent cultivation of fodder yeast. The aqueous extract obtained by treating the active sludge with water at a temperature of 80-100 ^{° C} for 10-60 min [1].

The disadvantage of this method is the significant heat consumption for obtaining an aqueous extract, comprising 5-65% of the volume of the substrate. Furthermore, it is necessary re-cooling the substrate to the fermentation temperature (28-36 ° ^C).

Known method of preparing a nutrient medium for the growth of microorganisms by acid hydrolysis of the activated sludge suspension with a solids content of 0,5-99,5% at 80-150 ^{° C} for 1 hour followed by neutralization of the hydrolyzate [2].

 The disadvantages of this method are the low quality of the substrate and the additional consumption of acid for the hydrolysis of activated sludge and a neutralizing agent for its subsequent neutralization.

Closest to the proposed invention in technical essence and the achieved result is a method of preparing a nutrient substrate for growing fodder yeast, which ennobles the substrate of plant origin, neutralizes it with an alkaline hydrolyzate of activated sludge, separates suspended solids, cools and introduces nutrient salts into the neutralizer, followed by the cultivation of yeast. Alkaline hydrolysis of activated sludge is carried out with a 0.5-10% solution of alkali metal hydroxide at a concentration of activated sludge of 10-60 g / l, a temperature of 20-150 ^about C for 15-60 minutes [3].

 The disadvantage of this method is the low quality of the nutrient substrate.

 The purpose of the invention is improving the quality of the substrate.

This is achieved by the fact that in the method for preparing a substrate for growing fodder yeast, including alkaline hydrolysis of protein-containing waste, acid hydrolysis of plant materials, refinement of an acid hydrolyzate, its neutralization with an alkaline hydrolyzate of protein-containing waste, separation of suspended solids, cooling and introduction of nutrient salts into the resulting neutralizer, followed by growing yeast, hydrolysis of protein-containing wastes with a concentration of 1-8 g / l is carried out with a 15-25% aqueous solution of ammonia at a temperature (-30) - (+80) ^о С for 3-60 minutes, and activated sludge from sewage treatment plants, sludge sediments of fermentation or yeast-growing tanks are used as a protein-containing waste. The use of concentrated ammonia solution as a hydrolyzing agent allows for mild alkaline hydrolysis of protein-containing wastes without significant decomposition of enzymes, vitamins, amino acids and other biologically active substances. When the concentration of ammonia is less than 15%, it is not enough for hydrolysis of protein-containing waste. The upper limit of ammonia concentration is determined by its solubility in water. The concentration of protein-containing waste is determined by the hydrolysis conditions. At a concentration of more than 8 g / l, partial decomposition of biologically active substances occurs, and at a concentration of less than 1 g / l, the concentration of biologically active substances is insufficient to improve the quality of the nutrient substrate.

Increasing hydrolysis temperature over 80 ^{° C} causes growth substances decay and deterioration of substrate quality. The lower temperature limit is determined by the freezing temperature of the reaction mixture. An increase in the hydrolysis time of more than 60 minutes leads to the decomposition of growth substances, and with a hydrolysis time of less than 3 minutes, the hydrolysis of protein-containing wastes does not have time.

 From the literature it is not known the use of aqueous ammonia for the alkaline hydrolysis of protein-containing waste and is proposed for the first time.

PRI me R 1. Prepare a solution (suspension) of sludge sludge yeast tanks (TAN) with a concentration of 1.7 g / l of dry matter in a 20% solution of ammonia. The slurry was hydrolyzed for 40 min at 20 ° ^C. To 1 liter of vegetable raw hydrolyzate obtained by hydrolysis of a mixture of sawdust softwood and hardwood (ratio 1: 1) 0.5% solution of sulfuric acid at a temperature of 170 ^{° C} was added alkaline fermentation tank sediment hydrolyzate to an acid hydrolyzate pH of 4.0. Neytralizat maintained under continuous stirring for 15 minutes at 75 temperatupe ^C. The substrate was cooled to 38 ^{° C,} separated by filtration from the separated suspended solids, aqueous extract administered MAP and potassium chloride of 2.5% P ₂ O ₅ and 1.7 % K ₂ About the mass of reducing substances (RV) of the substrate. Candida scottii U-882 yeast is used as seed material (hereinafter, numbers of cultures of microorganisms obtained from the All-Union Collection of Industrial Microorganisms of the All-Russian Research Institute of Genetics are indicated). The biomass yield is 57–78% of the RV substrate.

 According to the known method [3], the yeast biomass yield is 48.5% of the RV substrate.

PRI me R 2. Prepare a suspension of precipitation of fermentation tanks (OBH) with a concentration of 2 g / l in a 15% solution of ammonia. Hydrolysis is carried out at a temperature of -18 ^about C for 50 minutes The preparation of the substrate is carried out according to the conditions of example 1.

 As a seed, a culture of the yeast-like fungus Trichosporon cutaneum U-225 is used. The biomass yield is 59.37% of the RV substrate.

PRI me R 3. Prepare a suspension of sediment local treatment facilities with a concentration of 6 g / l in a 15% solution of ammonia. Hydrolysis is carried out at 50 ^about C for 15 minutes The preparation of the substrate is carried out according to the conditions of example 1.

 The seed culture used is the yeast culture Hansenula anomala Y-1184. The biomass yield is 53.14% of the RV substrate.

 The results of growing yeast on acid hydrolysates of wood raw materials neutralized by ammonia hydrolyzate obtained with other values of the parameters of hydrolysis of protein-containing waste are shown in the table.

 Thus, the proposed method allows to increase the yield of yeast from the radioactive substances by 14-19% compared with the known method and to eliminate the discharge of protein-containing waste polluting the environment.

Claims (2)

1. A METHOD FOR PREPARING A NUTRIENT SUBSTRATE FOR GROWING FODDER YEAST, including alkaline hydrolysis of proteinaceous wastes, acidic hydrolysis of vegetable raw materials, its refinement, neutralization of alkaline hydrolyzate of proteinaceous wastes, separation of suspended solids, cooling and introduction of temperature-neutralizing hydrolysis, waste is carried out with a 15 - 25% aqueous solution of ammonia at a concentration of protein-containing waste 1 - 8 g / l at a temperature of minus 30 - plus 80 ^o C in 3 to 60 minutes  2. The method according to p. 1, characterized in that as a protein-containing waste use activated sludge treatment plants, sludge sludge fermentation or yeast tanks.

Images