Spore production of Penicillium roqueforti by solid state fermentation: Stoichiometry, growth and sporulation behavior

Abstract

The development of Penicillium roqueforti on buckwheat seeds proceeds roughly into four steps, involving a lag phase and three growth phases. First, it appears as a spore germination and external colonization of the grains by the mycelium. Then, mainly external sporulation and internal colonization of the seeds occur and finally internal sporulation takes place. The Stoichiometry of the growth and the sporulation is established. Kinetic experiments performed in a fixed bed reactor show that the growth of the microorganism (biomass production) may be estimated by the protein content of the medium. This growth occurs with a very low mu(max) value close to 0.030 h(-1). The chitin content of the medium is an indicator of the sporulation, just as the metabolic liquor (mainly water) produced during the course of a cultivation. The values of the observed respiratory quotient are close to those predicted by stoichiometry.

Growth and sporulation stoichiometry and kinetics ofConiothyrium minitans on agar media

“…The ash content was assumed to be 5% for mycelium and 3% for spores based on results with P. roqueforti and M. anisopliae (Desfarges et al, 1987;Dorta et al, 1996).…”

Growth and sporulation behaviour of Penicillium roquefortii in solid substrate fermentation: effect of the hydric parameters of the medium

“…Chitin content of the medium did not allow estimation of mycelium formation when P. roquefortii was cultured on buckwheat seeds because the spores also contained this polymer (Desfarges et al 1987). Protein enrichment of the medium might give mycelium synthesis only if mineral nitrogen was used as the substrate (see before).…”

“…Assuming that the nitrogen content in the mycelium was the same as for spores (Desfarges et al 1987), it was possible to cal- Initial water (g/glDM)…”

“…Previous studies on the growth and sporulation of P. roquefortii on buckwheat grains have shown that the treatment of the substrate prior to cultivation is of critical importance and material balances demonstrated that carbon limitation never occurs during fungal development (Desfarges et al 1987;Larroche et al 1988). More recently, have hypothesized that mycelium formation involved passive water moving from substrate to microorganism in order to synthesize fresh biomass.…”

Submerged Liquid Culture for Production of Biomass and Spores ofPenicillium

“…To overcome these disadvantages, spore production in submerged liquid culture is presented as a promising alternative to Roux flasks and has been the subject of several debates of the scientific community in this area (5,6,7) . The submerged liquid culture process consists of growing an organism, most of the time from microbial origin, in a defined liquid medium in a tank called fermentor, which can be aerated and/or agitated.…”