Construction of Recombinant Producers of Enzyme Preparations for Fodder Production by Means of Expression System Based on Penicillium verruculosum Fungus

Abstract

Using the expression system based on the recipient strain Penicillium verruculosum 537 (ΔniaD) and promoter of the cellobiohydrolase 1 gene, producing strains were created. That made it possible to obtain new enzyme preparations (EP) for feed production, which are characterized by a high content of exodepolymerases (endo-β-l,4-glucanases and endo-β-l,4-xylanase), degrading non-starch polysaccharides (NSP) of grain cereals used in feed. The content of the endodepolymerases in new EP was 44-68% of the total protein content (compared with 15% in the case of the recipient strain), the content of exodepolymerases (cellobiohydrolases) fell to 8-26% compared to 60% in the case of the EP, obtained using recipient strain. New EP had high specific activity of endodepolymerases, which is 1.8-4.6 times higher than for the EP obtained with the recipient strain; the specific activity of exodepolymerases decreased in 2,0-3,7 times. New EP showed endoglucanase and xylanase activity in a wide range of pH and temperature, including the physiological value of these parameters (pH 3 and 7 and Г=37-38 °C); characterized by a high stability of endodepolymerases under the influence of digestive proteases (pepsin and trypsin), as well as the stability of ndodepolymerases under granulation conditions of animal feed (80 °C). The xylanase of the new EP was not inhibited by the inhibitors of cereal proteins. An experimental batch of new EP was manufactured by the enzyme-producing plant "Agroferment" and tested in broiler and pig feeding. The input of new commercial EP into broiler diets has had a positive impact on the safety of chickens, increasing their live weight and reducing feed cost. The supplementation of commercial EP into pig ration also led to positive results during feeding, contributed to the increase in the average daily growth of pig biomass, reduced feed consumption, protein and metabolic energy per unit of live weight gain, improved digestibility and assimilability of feed nutrients, especially of raw fiber and NSP. Feed enzyme preparation, xylanase, endoglucanase, non-starch polysaccharides, Penicillium verruculosum Funding-The work was done with the financial support of the Ministry of Science and Higher Education (State Task 0104-2019-0009).