RU1267788C - Method of purifying hydrolysate of plant raw - Google Patents

Description

 The invention relates to the microbiological industry and can mainly be used for cleaning hydrolysis media in the production of fodder yeast.

 The aim of the invention is to increase the degree of purification of the hydrolyzate and accelerate the cleaning process.

 The method is as follows.

 In order to separate suspended particles, a cationic high molecular weight flocculant is introduced into a semiproduct of hydrolysis-yeast production (hydrolyzate of plant raw material cooled by self-evaporation or its cooled neutralizer). A flocculant, for example, poly-4-vinyl-N-benzyltrimethylammonium chloride (VA-2 or VPK-101), which is a quaternary ammonium salt based on polystyrene and polyvinyltoluene, a polymer based on isopropyl ether polydimethylaminoethyl methacrylate 21-polyacrylic ester of ethyl acetate acids (Sanflock CH-799r); polyethyleneimine (Epaflock-2); and polydimethyldiallyl ammonium chloride (VPK-402) is introduced in an amount of from 0.5 to 50 mg / l, which leads to the formation of large dense flakes and their rapid deposition in settlers.

 The increase in the degree of purification and acceleration of this process is explained by the following.

 Along with substances of ligno-humic nature in the hydrolyzate of plant materials, there is a complex of condensed furan compounds with a variable set of functional groups (hydroxyl, carbonyl, carboxyl) that provide individual fractions of these impurities with isoelectric points in the pH range from 3 to 6, i.e. anionic properties. Therefore, cationic high molecular weight flocculants enter into chemical interaction with substances of the ligno-humic complex and condensation products of furan compounds with the formation of polymer bridges between flocculated particles. As a result, slightly dissociated hydrophobic compounds are formed, which rapidly precipitate. Thus, cationic flocculants are specific reagents in relation to a number of impurities of the hydrolyzate of plant materials.

 Along with colored impurities, cationic flocculants bind and remove negatively charged suspended solids, microorganisms, and other undesirable impurities from the solution.

 The method is illustrated by the following examples.

PRI me R 1 (prototype). The experiments were carried out with a production hydrolyzate neutralized to a pH of 4.2. Characterization of the neutralizer: concentration of PB is 3.05%; the content of colloidal substances is 1.41 g / l (100% control); concentration of dyes color 700 pcs (100% control). The concentration of dyes is determined by the optical density, and the content of colloidal substances by a known method. 2L neytralizata it is having a temperature of 80 ° ^C, basified with ammonia solution to pH 5.4 and added, with stirring, 3,895 g of Al ₂ (SO _{4) 3.} 18 Н ₂ О (based on 1 g of anhydrous aluminum sulfate per liter of substrate).

 After the salt has dissolved, the pH is again adjusted to 5.4 with ammonia water, stirred for 15 minutes, 20 ml of a 0.10% aqueous solution of flocculant-polyacrylamide are added (dose of 10 mg / l). The solution was stirred for another 15 minutes, after which the dependence of the absorbance of the neutralizer on the settling time was determined. The duration of sedimentation of the neutralizer is 30 minutes After separation of the precipitate, the solution is acidified to pH 4.2. The concentration of dyes in the neutralized purified 65.0% to the control, the colloid content of 85.0% to the control. The purified neutralizer is used later in the cultivation of feed yeast.

PRI me R 2. To 5 l of the neutralizer, according to example 1, having a pH of 4.2 and a temperature of 80 ^about C, add 50 ml of a 0.10% solution (dose of 10 mg / l) of a cationic high molecular weight flocculant BA- 2 (VPK-101). The solution was stirred for 30 minutes. Settling time 15 min. After separation of the precipitate, the concentration of coloring substances in the solution was 36.5% of the control, the colloid content of 52.0% of the control. The purified neutralizer is used later in the cultivation of feed yeast.

 PRI me R 3. To 100 ml of neutralizer, according to example 1, add 1.0 ml of a 0.1% solution (dose of 10 mg / l) of cationic high molecular weight flocculant BA-212. The solution was stirred for 30 minutes. The settling time is 12 minutes. The concentration of dyes in the solution is 38.6% of the control, the colloid content of 85.0% of the control.

 PRI me R 4. To 100 ml of neutralizer, according to example 1, add 0.5 ml of a 0.01% solution (dose of 0.5 mg / l) of cationic high molecular weight flocculant Sanflock SN-799 p. The solution was stirred for 30 minutes. The settling time is 8 minutes. The concentration of dyes in the solution is 51.8% to the control, the colloid content is 67.5% to the control.

 PRI me R 5. To 100 ml of the neutralizate, according to example 1, add 1 ml of a 0.1% solution (dose of 10 mg / l) of cationic high molecular weight flocculant Epaflock-2. The solution was stirred for 30 minutes. The settling time is 15 minutes The concentration of dyes in the solution is 49.7% of the control, the colloid content of 72.7% of the control.

Example 6. The initial hexose hydrolyzate is obtained by percolation hydrolysis of cellolignin of vegetable pentazane-containing raw materials (corn cobs and cotton husks) and is cooled by self-evaporation. 1 liter of hydrolyzate (pH 1.2) is neutralized to pH 3.0 with lime milk, and then to pH 4.4 with ammonia water. Neutralizate characteristic: RV content 2.23%; concentration of coloring substances; color 1190 ^о pcs (100% control); colloid content 1.20 g / l (100% control). The resulting neutralizer is cooled and used in this example and in the following. 0.5 ml of a 1% solution (dose of 50 mg / l) of a BA-2 cationic high molecular weight flocculant (VPK-101) is added to 100 ml of neutralizate. The solution was stirred for 30 minutes. The time for settling the solution is 20 minutes. The concentration of dyes in the purified neutralizer is 54.0% of the control, the colloid content of 61.0% of the control.

 To 100 ml of hydrolyzate (pH 1.2) add 0.5 ml of a 1% solution (dose of 50 mg / l) of the cationic high molecular weight flocculant BA-2 (VPK-101). The hydrolyzate is neutralized to a pH of 3.0 with lime milk, and then to a pH of 4.4 with ammonia water. The solution was stirred for 30 minutes. The time for settling the solution is 20 minutes The concentration of dyes in the purified neutralizer is 54.0% of the control, the colloid content of 61.0% of the control, i.e. the introduction of a flocculant into the hydrolyzate before it is neutralized does not affect the deposition rate of colloids and the degree of purification of the hydrolysis medium.

 PRI me R 7. The experiments are carried out with the same neutralizer as in example 6. To 100 ml of neutralizer add 2.0 ml of a 0.1% solution (dose of 20 mg / l) of cationic high molecular weight flocculant VPK-402. The solution was stirred for 30 minutes. Settling time 18 min. The concentration of dyes in the solution is 58.5% to the control, the colloid content is 67.3% to the control.

 PRI me R 8. The experiments are carried out with the same neutralizer as in example 6. To 100 ml of neutralizate add 0.3 ml of a 0.01% solution (dose of 0.3 mg / l) of cationic high molecular weight flocculant Epaflok- 2. The solution was stirred for 30 minutes. Settling time 32 min. The concentration of dyes in the solution of 76.3% to the control. At low doses of flocculant, the results are worse than in example 1.

 Thus, for clarification of hydrolysis media, cationic flocculants should be used in amounts of 0.5-50 mg / L. At a dose of less than 0.5 mg / L, the settling time of the neutralizer increases and the clarification effect worsens. At doses of large 50 mg / l with a slight increase in the clarification effect, the consumption of flocculants becomes unreasonably high.

 The results of the experiments in examples 1-8 are shown in table. 1.

 The best results for the purification of hydrolysis media were obtained using the VA-2 flocculant (VPK-101). On neutralizers purified by this flocculant (example 2) and the prototype (example 1), a comparative cultivation of fodder yeast (example 9) was carried out.

 PRI me R 9. Conducted 3 experiments on the cultivation of feed yeast on the neutralizer according to examples 1-5. In the control experiment, 5 l of the neutralizate is directed to the cultivation of fodder yeast according to the usual technology for the installation of continuous action. To do this, the neutralizate is diluted twice with tap water to a content of 1.50%; it is enriched with the nutrient salts of nitrogen, phosphorus, potassium according to the calculation based on the content of yeast in the cell: nitrogen 8% phosphorus 4% potassium 3%. The substrate is sterilized in an autoclave for 20 minutes. After cooling, sowing pressed Candida scottii KS-2 yeast is introduced into it and fodder yeast is grown according to the generally accepted method in a continuous way with automatic adjustment of pH 4.5 by neutralizing the substrate with an ammonia solution.

Duration of the cultivation in steady state for 17 hours, at an average flow rate of the substrate 229 ml / hour and 37 ° ^C.

 In the control experiment, the output of A. with. yeast from 45.8 ± 1.3% of rV, confidence probability P 0.95. The productivity of the fermenter is 1.46 g / l˙h. The color of the obtained yeast is dark gray with a brown tint.

PRI me R 10. For the cultivation of yeast using 2 l of the neutralizer described in example 1. The preparation of the substrate and the cultivation of fodder yeast is carried out according to the same methodology as in example 1. Yield a.s. yeast is from 47.7 ± 1.2% of PB, P 0.95. Productivity of the fermenter 1.78 g / l˙h. The color of the yeast is gray. Received an increase in the yield of yeast in relation to the control experiment by 1.9%
PRI me R 11. For the cultivation of yeast using 5 l of the neutralizer described in example 2, with a cationic flocculant VA-2 (PVK-101). The preparation of the substrate and the cultivation of yeast is carried out according to the same methodology as in the control experiment. When growing yeast in a continuous manner on a substrate purified by a cationic flocculant, deposits of colored substances on the glass walls of the fermenter are not observed, as was the case in Example 9. Substrate foaming is also significantly reduced. The time for growing yeast in steady state is 15 hours at an average substrate flow rate of 257 ml / h.

 Output A.S. fodder yeast is 52.2 ± 1.2% P 0.95. The productivity of the fermenter is 2.02 g / l˙h. The condition of the yeast obtained is good. The color is light cream, the cells have a thin shell, homogeneous protoplasm, normal budding and branching structure.

 Received an increase in yeast yield in relation to the control experiment by 6.4% in relation to the prototype by 4.5% of RV (table. 2). The results of the cultivation of yeast in examples 9-11 are shown in table. 2.

 Thus, the proposed method allows to increase the degree of purification of hydrolysis media from dyes 1.1-1.8 times; from colloidal 1.0-1.6 times in relation to the prototype. The cleaning process is accelerated, the duration of colloid sludge in hydrolysis media is reduced from 30 to 8-20 minutes. Precipitation after settling of the neutralizate (flocculant) is more dense. The amount of monosaccharides adsorbed by such precipitates decreases on average 1.4 times. The quality of the target product (fodder yeast) grown on purified substrates is improved. The yeast becomes lighter, and the yield of yeast increases by 4.5% of PB compared with the prototype. When using the proposed method also increases the productivity of fermenters from 1.78 (prototype) to 2.2 g / l · h. Thus, the invention provides an increase in the degree of purification of the hydrolyzate and acceleration of this process.

Claims (1)

 METHOD FOR CLEANING HYDROLYZATE OF VEGETABLE RAW MATERIALS, which provides for cooling the hydrolyzate by self-evaporation, neutralizing it, separating suspended solids during the introduction of the flocculant and cooling the neutralizate, characterized in that, in order to increase the degree of purification of the hydrolyzate and accelerate the cleaning process, flocculants use cationic high or after neutralization in an amount of from 0.5 to 50 mg per 1 liter of hydrolyzate.

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