Influence of morphology and rheology on the production characteristics of the basidiomyceteCyathus striatus

Abstract

The influence of the pellet morphology of the basidiomycete Cyathus striatus on the production of the antibiotics striatals A, B, and C was investigated. The main operating parameters in fermenters of different sizes were the tip speed and the volumetric power input. Different methods were developed for quantification of morphological characteristics. The apparent viscosity of the suspension was measured with a cylinder rheometer. Sediment density was measured with a sedimentation apparatus. Particle size distributions were recorded with an image analysis system. By means of the presented measuring methods, morphological characteristics could be determined and enabled an early assessment of the fermentation course and the antibiotics production. During the exponential growth phase of the fungus the relative sediment height correlated with the biomass concentration. The pellet morphology at this stage influenced the later production of striatals. The yield of the striatals was markedly influenced by pellet size and sediment density. Since these morphological characteristics determine the rheological properties of the culture the measurement of the apparent viscosity of the culture in the production phase allowed predictions of the production yield. © 1998 John Wiley & Sons, Inc. Biotechnol Bioeng 59: 525–533, 1998.

Effect of transport phenomena of Cladosporium cladosporioides on decolorization and chemical oxygen demand of distillery spent wash

“…Several studies have shown that fermentation broths containing high concentrations of filamentous microorganisms are highly viscous and are characterized by shear-rate-dependent viscosities and by a yield stress (Ju et al 1991;Berovic et al 1993;Goudar et al 1999). In case of production, the yield is predicted by the measurement of the apparent viscosity of the culture in the production phase, and the morphological characteristics directly determine the rheological properties of the culture broth (Gehrig et al 1998). The non-Newtonian behavior is relatively predominant at lower shear rate and at higher mycelial concentration.…”

“…The rheological behavior is closely related to the morphology and biomass concentrations (Blanch and Bhavaraju 1976;Charles 1978;Metz et al 1979;Tucker and Thomas 1993). The broth rheology determines the transport phenomena in bioreactors and is considered to be the key factor for getting an improved yield of the targeted product (Berovic et al 1991;Gehrig et al 1998). Generally two types of growth forms the filamentous and pelleted can be observed during a fungal fermentation.…”

Measurement of bubble and pellet size distributions: past and current image analysis technology

“…The measurement procedure often is repeated for several samples, then the size distribution is calculated by averaging [82]. Furthermore, size distribution data have been linked with off-line data to plot the percent dry biomass versus pellet diameter [58] or to obtain the pellet density (division of dry cell weight by pellet volume), q p [28].…”

“…Key quantities are the percentage of pellets [109] or the number frequency of pellets as function of size (e.g., radius) [86,103]. Other obtainable quantities include the pellet concentration, pellet volume (sum of individual particle volumes), average diameter (e.g., d a ), volume concentration (volume of pellets per liter of sample volume), cumulative volume concentration curve (addition of individual volume concentrations from 0 to d i ), normalized cumulative volume concentration curve (d max = 1), and median value of diameter, d 50 (diameter for which normalized cumulative volume curve is 0.5) [28].…”

Process Parameters Affecting the Synthesis of Natural Flavors by Shiitake (Lentinula edodes) during the Production of a Non-Alcoholic Beverage

“…Leisola and Fiechter also reported that P. chrysosporium pellets with an average diameter of 0.1-0.2 cm produced the maximal lignin peroxidase activity (LiP) [16]. On the other hand there are investigations with basidiomycetes which state that the oxygen limitation in pellets can promote the secondary metabolite production [17][18][19].…”