Biosynthèse des protéines par des bactéries et des moisissures cultivées sur milieu de lactosérum

Abstract - Protein Biosynthesis by Bacteria and Moulds when Cultivated on Whey Medium
Studies were conducted on protein biosynthesis by following mould strains: Penicillium roqueforti WR-16, Oospora lactis-15, Zygorrhynchus meelleri LECK-81, Rhizopus oligosporus CBS 33962 which were cultivated on whey medium.
The intensity of this process was found to depend on the quality and amount of nitrogen compounds as added to the medium, as well as on thechnological parameters, such as time and temperature of cultivation. To less extent, it depended on the original acidity of the medium.
The process of protein biosynthesis by moulds appeared to be intensifield by preliminaryly accumulated biomass of Propionibacterium shermani or Escherichia coli which was followed by the cultivation of moulds.
Amounts of proteins which were obtained from whey medium by associated biosvnthesis of bacteria and moulds, varied from 12,1 to 23,3 g / l.
Mixed biomass of moulds and bacteria was characterized by high content of B-vitamins and nucleic acids. Low amounts of bacterial inhibitors were also found to be present in the biomass. The quantitative composition of amino acids depended on mould species and on cultivation procedures.
Biological values for the mould biomass and the mixed biomass of bacteria and moulds were 83-89 and 95-97, respectively. The results of biological values require further affirmation by experiments with animals

Résumé - On a étudié la biosynthèse des protéines par des moisissures : Penicillium roqueforti WR-16, Oospora lactis-15, Zygorrhynchus meelleri LECK-81, Rhizopus oligosporus CBS 33962, cultivées sur milieu de lactosérum.
La culture associée de bactéries E. coli et des moisissures permet d'obtenir, dans des conditions optimales, 23 g de protéines environ à partir de 1 l de lactosérum. La biomasse qui était obtenue contenait des quantités relativement élevées d'acides aminés limitants, tels que la méthionine 2-2,5 g / 16 g N, la lysine 8,5-9 g / 16 g N et le tryptophane 1,8-2,5 g / 16 g N. La valeur de l'index d'Oser variait de 83-85 pour la biomasse de moisissures et de 95-97 pour la biomasse mixte de bactéries et de moisissures. Outre cela, la teneur élevée en vitamines B₁ et B₂ et en acides nucléiques confirme que la biomasse mixte de bactéries et de moisissures est un composant précieux de la ration alimentaire animale