Growth efficiency of thielavia terrestris mycelial structures

Abstract

The growth energetic efficiency (7) of two mycelial forms of Thielavia terrestris (pellets and diffused form) was studied by different methods. 7 Values determined by the pulse method are similar for the two forms, but the 7 values determined by C balance for pellets were lower than those for diffused mycelium. These balance data prove that pellets yield more extracellular products than the diffused mycelium form, which is also confirmed by experimental data for different amounts of carbon in the culture fluid.Growth efficiency can be determined by various methods based on t,he principles of mass and energy balance. The estimates most frequently used are the biomass and substrate balances. However, growth efficiency determination according t o oxygen balance (particularly by the pulse method) is simpler and more accurate; a s it makes possible the immediate fixation of changes in the physiological condition of microorganisms and the determination of comples substrate utilization efficiency [ 13. Earlier the possible use of this method for evaluating the growth efficiency of heterotrophic bacteria [2], h-yphalic and yeast forms of microscopic fungi [3] was shown. The aim of the present stutly is the comparative investigation of the growth efficiency of two mycelial structures (hyphalic and pellets) by different methods as well as by pulse additions. Materials and 3IethodsMicromyanisms Thermophilic ascomycetes Thielacia terrestris from the collection of the Institute of Jlicrobiology and Virology of the UkSSR Academy of Sciences were used. CultivulionAt dl cultivation stages, both for obtaining inoculate in the form of vegetative mycelium and for growth in the chemostat CHAPEK medium was used. 1% glucose solution was the carbon source.Vegetative mycelium was obtained from spore inoculum for diffused mycelium 10' spores/ml, pH of the medium: 4.0; for pellets lo5 spores/ml, pH: 7.0. The cultivation was performed in an AKCUM-2M fermenter equipped with automatic controls for pH, PO, and temperature. The working volume of the apparatus was 5 1. The process tempera-:$ Acta Biutectinol. 11 (1991) 4

Development peculiarities of mycelial structures of Thielavia terrestris under batch conditions

“…Проведенный нами ранее сравнительный анализ уравнений мате риального баланса роста различных мицелиальных структур Th. terrestris позволил установить, что при развитии гриба в виде пеллетов иа одну молекулу глюкозы потребность в кислороде ниже, чем при диффузном росте [12,27]. Рост в виде пеллетов отличается от диф фузного более низким выходом биомассы, высоким образованием мета болитов и меньшим выходом продуктов полного окисления глюкозы: С0 2 и Н 2 0.…”