CS200792B1 - Microbial biomass production method - Google Patents

Description

The present invention relates to a method for producing microbial biomass by yeasts of the genus Trichosporon isolated from waste wood and paper processing industries capable of utilizing non-traditional substrates: treated, thickened prehydrolysate, kraft pulp, oxylcell syrup and wood xylose syrup.

The lack of traditional raw materials and concerns about their exhaustion have turned research attention to new resources in recent decades, including wood waste. Isolation and the stage of various microorganisms capable of utilizing them for the preparation of proteinaceous biomass and cellulolytic enzymes is therefore a serious theoretical problem and is of great importance for practice. Isolation of mono and oligosaccharides from these wastes and their subsequent use as carbonaceous sources is disadvantageous from the technological and economic point of view and the most suitable way is in searching for microorganisms able to use untraditional carbonaceous sources - wastes without major adjustments demanding on technological equipment.

Of the microorganisms, yeast is the most suitable protein producer, their dry matter contains 40 to 65% protein and has a similar amino acid composition to animal proteins except for amino-containing amino acids.

Growing yeasts on wood hydrolysates and wastewater in the woodworking industry to obtain feed protein is the subject of many washing. However, there are rare references to the ability of yeast to break down polysaccharides, cellulose

200 792

200,782 and xylan, respectively hemicelluloses. The ability to utilize cellulose was studied in the genus Trichosporon (C. Dennis J. Gen. Bíocrob. 71, 409 1972) and some strains of the species Areobasidium pullulans (B. Plannigan, Trans. Brit. Mycol. Soc. 55; 277, 1970) in the strain. Cryptococcus diffluens, which can be used and used! for the production of protein feed (J. Hojnoš et al. Pap. Cellulose 27, V. 31, 1972).

The utilization of sulphite leaches by fermentation is evident, their saccharide components are used to produce ethanol and feed yeast (Vraná, Paper et al. 15, 74 (1960), Bárta et al. Paper and Cellulose 23, 333 (1968)). kraft treatments have not been used microbially yet, and are used and directly fed (Dukovansky, Paper and Cell. 30/10 (1975)).

The present invention is directed to a method of producing microbial biomass by culturing on treated concentrated prehydrolysate or syrup flowing after production of xylose or wood hydrolyzate, characterized in that ammonium sulphate, acidic potassium phosphate and yeast autolysate are added to carbon sources to adjust the pH of the medium. , 8 to 5.5, and the sterile medium is inoculated with Trichosporon pullulans 6 / A-CCY 30-1-4 or Trichosporon pullulans 6 / B-CCY 30-1-5 or Trichosporon cutaneum 15 / A-CCY 30-5- 13 and cultured at 28 ° C for 3-4 days, then the culture is centrifuged, washed with water and dried, preferably by lyophilization.

Trichosporon strains were isolated from the waste sciences of the woodworking and paper industries and showed no pathogenic and toxic properties in their characterization. Strains They are stored in the Czechoslovak Yeast Collection in Bratislava under the following straps:

Trichosporone pullulans 6 / A-CCY 30-1-4

Trichosporone pullulans 6 / B-CCY 30-1-5

Trichosporone cutaneum 15 / A-CCY 30-5-13.

These strains are characterized by producing ursase, assimilating lysine and triptophan and forming true mycelium - artrohonidia, not using lactose, ribose, trehalose, 1-arabinose, fucose, arabitol, ribitol, inulin, inositol. They distinguish aa in the assimilation of potassium nitrate, the Trichosporon pullulans strains assimilate potassium nitrate, the Trichosporon cutaneum strain does not assimilate potassium nitrate, and in the assimilation of sugars as shown in Tab. 1. Observing the optimal growth temperature of 5 ° C, 28 ° C and 40 ° C best growth of all the strains examined at 28 ° C

As substrates, the only carbon sources for the production of microbial biomass and used:

1. thickened pre-hydrolyzate resulting from the sulphate production of beechwood cellulose.

Biologically, the prehydrolysates include the saccharides A-xylose, 1-arabinose, D-glucose, D-galactose, D-mannose, xylose oligosaccharides as well as non-cleaved hemicelluloses.

2. Syrup in the production of xylose - remaining as a by-product in the production of crystalline D-xylose from beech wood, which contains the carbohydrates D-xylose, arabinose, rhamnose, gslactose, mannose. 3. Wood hydrolyzate - obtained from beech sawdust by treatment with 1% sulfuric acid at 120 ° C for 2 hours, purified by carboraffin and desalinated with ion exchangers.

Example 1

Prepare a culture medium of 1 liter. 100 ml of concentrated prehydrolysate (xylocell), 3 g of ammonium sulfate, 1 g of potassium phosphate and 1 g of yeast autolysate are used, the pH of the medium is adjusted to 5. The sterile medium is inoculated with a yeast suspension of the genus Trichosporon and cultured on a reciprocating shaker 108 / min. at 20 ° C for 3 to 4 days. Thereafter, the culture is centrifuged, washed with water, the biomass is lyophilized or dried in another suitable manner.

During growth, the relationship between the growth of the culture and the loss of the carbon source substrate is monitored.

The biomass yield for the above strains was 4-6 g dry matter per liter. culture medium.

Example 2

The syrup remaining after production of xylosis is added to the culture medium of Example 1 so that the reducing agent content in the medium is 2%. The cultivation conditions were the same as those of Example no. 1, with substrate growth being also monitored during growth curve growth monitoring (optimal culture time for the strains of interest was 3-4 days). The biomass yield for the above strains was 4 to 7 g dry matter per liter of culture medium.

Example 3

To the culture medium shown in Examples 1 and 2 aa, the wood hydrolyzate is added as the only carbon source so that the reactive sugar content is 2%. Culture conditions as set forth in the previous examples. The optimum cultivation time for said substrate was 3 days and the biomass yield for said strains was 4-5 g dry matter per liter. culture medium.

Table no. 1 / a

strains Assimilation of nitrogenous substances Sugar assimilation kno ₃ lysine tryptophan ga Cle with Ma la Ce tr ra X with Trichosporon pullu- lans CCY 30-1-4 + + + + + + + wall. + wall. + Trichosporone pullulans CCY 30-1-5 + + + + + + wall. + + wall. + Trichosporon cutaneum CCY 30-5-13 + + + +

Explanation of abbreviations;

Ga - galactose

Glc - glucose

S - sucrose

Maltose

Lactose

Ce - cellobiose Tr - rehalosis Ra - rhamnose X - xylose So - sorbose

Table δ. 1 / b

strains Sugar assimilation Me A Fu Fu Gluc In Er Ri Man Mel starch urea Artkon Qal Trichosporone pullulans CCY 30-1-4 4 - _ - + - + - + + + + + Trichosporone pullulans CCY 30-1-5 + - - * + - + - + · + + + + Trichosporon cutaneum CCY 30-5-13 - + + +

V.vevetlenie akratiek:

Me - melibiosis R 1 - ribitol A - arebinoza Man - mannitol R - riboza Mel - melicitis Fu - fucoza Starch - starch formation test gluc - glucitol Urea - hydrolysis of urea in - inositol Artkon - artrokonidia Er - eyytritol Gal - galactitol

OBJECT OF THE INVENTION

Claims (1)

OBJECT OF THE INVENTION Method of producing microbial biomass by culturing on treated densified prehydrolysate or syrup remaining after xylose production or wood hydrolyzate, characterized in that ammonium sulphate, acidic potassium phosphate and quaternary autolysate are added to the carbon sources, and the pH of the medium is adjusted to 4.8 to 5.5 and the sterile medium is inoculated with Trichoaporon pullulans 6 / A-CCY 30-1-4 or Trichoaporon pullulana 6 / B-CGY 30-1-5 or Trichosporon cutaneum 15 / A-CCY 30-5-13 and cultured at 28 ° C for 3 to 4 days, then the culture is centrifuged, washed with water and dried, preferably by lyophilization.