CS201953B1 - Method of treating the hydrolysers of the agricultural refuse - Google Patents

Description

The invention relates to a process for processing hydrolysers of agricultural waste into feed proteins of yeast microorganisms without removing inhibitors.

Treatment of different agricultural wastes based on different lignocellulosic and other polysaccharide materials by acid hydrolysis yields a substrate for microbial mass biosynthesis using yeast microorganisms. These materials, due to the decomposition of the pentoses, contain a considerable amount of furol and other microorganism growth inhibitors. Prior processes for utilizing such raw materials have anticipated costly removal of inhibitors by adsorption or distillation prior to fermentation. When culturing yeast microorganisms, the hydrolyzate thus treated was neutralized to a pH of 4.5 to 5.

The above-mentioned drawbacks are eliminated by the method of processing of agricultural waste hydrolysers according to the invention, which consists in that the acid hydrolyzate of lignocellulosic or other polysaccharide materials is adjusted to pH = 6.0 to 7.0 with a suitable source of nitrogen and phosphorus. is removed and the clear supernatant is subjected to yeast aerobic fermentation at a pH of 6.0 to 7.0. The advantage of this process is that it is not necessary to remove the inhibitors by adsorption or distillation, except when obtaining them as a by-product. Under these conditions, the growth of yeast is fast enough compared to the rate of growth of the bacterial infection. Bacterial contamination occurs at pH 5, but to a lesser extent.

In the following, the present method of fermentative processing of acid hydrolysers to a bacterial mass is explained in more detail in the examples, although it is not limited thereto.

Example 1

A hydrolyzate obtained by acid hydrolysis of straw with HCl, which had a 7% refractometric dry matter, pH 1.9 and a fural content of 0.07%, was used. The hydrolyzate was fed with K 3 HPO 3 (1 g / L), (NH 4 / 2SO 4/1 g / L) and neutralized to pH 7.0. The precipitate formed was separated by centrifugation or sedimentation. The clear supernatant was inoculated with 1/20 to 1/10 yeast culture volume strain A 78 from the Department of Technical Microbiology and Biochemistry of the Faculty of Chemical Technology of the Slovak University of Technology in Bratislava and cultivated under aeration in a ban201953 shaker at 28 ° C. for 24 to 36 hours. A good sedimenting yeast biomass was obtained in a yield of 2.5 g / 100 ml of medium. In a medium prepared in the same way, with the difference that it was neutralized to pH 6 and the lower culture did not grow even after several days of cultivation.

Example 2

The straw hydrolyzate of Example 1 was neutralized to pH 7, clarified by centrifugation, and fed with a source of nitrogen and phosphorus. One liter of medium was inoculated with 50 ml of A 78 yeast culture grown in previous cultures. The inoculum used was partially infected with motile bacteria and cocci. 1: 100 ratio of bacteria to yeast count.

It was cultured non-aseptically in a 5 L laboratory fermentor under aeration for 72 hours with a state pH system with a registered oxygen consumption measured by Clark's polarographic electrode. Lowering the pH during cultivation below pH 6 by overdosing acid little results in a decrease in the intensity of respiration and yeast growth. Increasing the alkalinity of the culture medium to a pH of 8 by adding lye little results in a rapid proliferation of bacterial contamination. By reversing the acidity to pH 7 and incorporating the fermenter into the state pH system, bacterial contamination was significantly eliminated.

If an analogous fermentation was made non-aseptically at pH 7 on the hydrolyzate from which the inhibitors were removed by hot charcoal, it was not possible to produce yeast microbial mass for a massive bacterial infection. Bacterial contamination occurred even in non-aseptic fermentation conducted at pH 5, but to a lesser extent. Removal of a portion of the inhibitors with activated carbon allowed the pH to decrease below 6 during culture, but bacterial contamination grew faster than yeast cells and semi-continuous cultivation was not feasible. After 24 h. The periodic inoculation of the culture directly from the fermenter to the fermenter under non-aseptic conditions on animal waste hydrolyzate pH 6-7 allowed the yeast organisms to be maintained without overgrowing with bacterial contamination for more than 4 weeks.

Example 3

The acid hydrolyzate of the excrements from the large-fed pigs with an initial dry weight of 5.8% was neutralized by addition of lime to pH 4.5 and decolorized with 2% hot charcoal. After this treatment, the clarified solution had the following composition: 3.5% dry matter. 1.54% reducing agents, 1.2% total nitrogen, 0.1% phosphorus and 0.02% fural. One liter of the medium was inoculated with yeast culture strain A78. During the cultivation, a precipitate was formed which enveloped the yeast cells forming amorphous clumps. The growth of the culture followed by biomass formation and based on the rate of oxygen consumption was low. The same problems arose when a different water-soluble salt-solubilizing principle, e.g. NaOH.

When neutralized with lime or with a Ca / OH / 2 pH of 6-7, the culture medium thus prepared, even in the case without decolouration with activated charcoal, produced only a small amount of clots which, moreover, did not precipitate on the yeast cells and the culture showed intense growth accompanied by rapid growth. oxygen consumption. It has been shown that the addition of nitrogen and phosphorus sources is not necessary.

Claims (3)

A good sedimentation of the yeast biomass was obtained in a yield of 2.5 g / 100 ml of medium. In a medium prepared by the same method, the difference being that the pH value of 6 and the lower culture were neutralized. has not grown up for several days of cultivation. Example 2 The straw hydrolyzate in Example 1 was neutralized to pH 7, clarified by centrifugation and fueled with nitrogen and phosphorus sources. One liter of medium was inoculated with 50 ml of A 78 culture yeast from grown in previous cultures. The inoculum used was partially infected with moving cocci bacteria. The ratio of bacterial count to 1: 100. It was cultured non-aseptically in a 5 L laboratory fermenter under aeration for 72 hours with a pH state system with oxygen demand registration measured by a Clark Polarographic Electrode. Lowering the pH during cultivation below pH 6 by overdosing the acid results in a reduction in yeast respiration and growth. Increasing the quality of the culture medium to pH 8 by adding liquor results in a rapid increase in bacterial contamination. By adjusting the acidity to a pH of 7 and incorporating the fermenter into the pH system of the state, the bacterial contamination was significantly reduced. If the analogous fermentation is acne silane-aseptically at pH 7 on the hydrolyzate from which the inhibitors have been removed by the active heat sink, it has not been possible to produce yeast production microbial mass for a mass-bacterial infection. Although bacterial contamination occurred at a pH 5 of non-aseptic fermentation, it was largely less. Removal of a portion of the inhibitors by the activated carbon allowed the pH to be reduced to below 6, but the bacterial contamination grew faster than the cells of the yeast organisms, and semi-continuous culture was not possible. After 24 hours, the cultivation ratio of bacteria to yeast reached a value of 1: 1 to 2: 1, by periodically re-culturing the culture directly from the fermentor fermenter under non-aseptic conditions to animal wastes pH 6 to 7, keeping the yeast organisms free from bacterial contamination. weeks. Example 3 The acid hydrolyzate of the excreta of large-fed pigs with a dry solids of 5.8% was neutralized by the addition of lime to a pH of 4.5 and decolorized with 2% of the activated charcoal. For this treatment, the clarified solution had the following composition: 3.5% dry matter. 1.54% reducing feed, 1.2% total nitrogen, 0.1% phosphorus and 0.02% fural. One liter of medium was inoculated with yeast culture strain A 78. During the culturing, a precipitate formed which enveloped the yeast cells forming amorphous clumps. Growth of the culture monitored by biomass production and on the basis of the oxygen consumption rate bolmaly. The same problems arose in the case where the neutralizing salt used in the water-soluble, e.g. NaOH, was used for neutralization. In the case of neutralization with lime or Ca / OH / pH 6 to 7 ', the culture medium thus prepared, even in the absence of decolorization with charcoal, produced only a small amount of precipitates which, in addition, did not precipitate in yeast cells and the culture showed intense growth accompanied by rapid oxygen consumption. Addition of nitrogen and phosphorus sources is not necessary. SUBSTITUTE Process for the treatment of agricultural waste hydrolysates, characterized in that the acid hydrolyzate of lignocellulosic or other polysaccharide materials is adjusted to a pH of 6.0 to 7.0 with a suitable source of nitrogen and phosphorus LEVEL, with the resulting precipitate being removed and subjected to a clear supernatant yeast aerobic fermentation at pH 6.0 to 7.0,