UNIVERSITÉ PAUL CÉZANNE, AIX MARSEILLE III - IMEP

Résultats et discussion. Chapitre 3: Evaluation des facteurs de croissance
cultivation. Moyson and Verachtert (1991) have demonstrated that the growth of L.edodes is
initially associated to hemicellulose content of substrate, since hemicellulose and other water-
soluble sugars are mainly utilized during the active growth phase, prior to the breakdown of
lignin and cellulose. On the other hand, the use of OC supplemented with OMW caused in the
oxygen (O2) depletion could be the cause which reduces mycelial biomass development in
substrates (Ohga, 1990). Small air spaces present in OC supplemented may slow gas
exchange from deep within the interior of the substrate to the surface (Royse and Sanchez-
Vazquez 2001).
In many cases, different factorial designs were used in the literature for assessing the
effect of environmental factor on biological responses (Ranz and Lankmayr 2006; Swalley et
al., 2006; Purama and Goyal 2008). The factorial design and statistical analysis were
performed with NemrodW software (Mathieu and Phan-Tan-Luu, 2000). The combination of
moisture content, which was maintained at 50% (v/v) with the incubation of substrate in oven
for two days without forced aeration, allowed preventing any contamination of L. edodes
culture with filamentous fungi which are known as major antagonistic agent in mushroom
culturing (Savoie and Mata, 1999; Terashima et al., 2002; Kalmis and Sargin 2004). The
supply of culture with humidified air allowed gradual increase of the substrate moisture
contentand keeping the substrate with suitable moisture content.
The influence of the composition of the substrate on mushroom production characters
has been emphasized in recent studies (Philippoussis et al., 2001; Sunchez and Royse 2001;
Philippoussis et al., 2003). In the framework of the present study, the nutriment added to the
substrate and the spawn size were the main parameter that affected the growth of L. edodes.
This can be attributed to the nitrogen content, imported with addition of the mineral solution,
which exercised a negative effect on mycelial growth. Indeed, Nitrogen has been recognized
as a growth limiting factor for the L. edodes cultivation (Boyle 1998; Kalberer 2000), while
recently a positive correlation of mycelial growth to low C/N ratio values of substrates used
for the cultivation has been demonstrated as well (Philippoussis et al., 2003; 2007). However,
in L. edodes cultivation on synthetic composite media (OTL + OC + OMW), supplementary
nutritive solution should not be used. Otherwise, when the nutritive solution was added, we
observed that the risk of contamination of the growth media was increased considerably.
Similar findings were reported by Schunemann (1988).
The data obtained on polyphenol removal from the substrate by the culture of
L. edodes, showed that there was a negative effect of mineral solution added to initial
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