Abstract

This work evaluates the effect of different carbon and nitrogen sources on conidiophore and conidia formation in Penicillium sp. HC1, a cellulolytic and xylanolytic fungi arousing industrial interest. A factorial design was used having two variables: A carbon source (glucose, sucrose, cassava starch, wheat bran, and rice flour) and a nitrogen source (tryptose, yeast extract, (NH₄)₂HPO₄, and KNO₃). The resulting 20 combinations were evaluated in both solid and liquid medium. Different C:N ratios (5:1, 10:1, 20:1, and 40:1) were also evaluated for one of the combinations. The results revealed the influence of both carbon and nitrogen sources on conidiophore and conidia morphology and the amount of conidia produced; however, this depended on culture condition. A particular culture’s condition could also influence conidia tolerance to stressful conditions; conidia having close to 100% tolerance were obtained in liquid media having complex carbon sources and inorganic nitrogen sources. Regarding the C:N ratio, it was found out that nitrogen limitation increased conidia tolerance for both conditions (solid, liquid), the effect being more noticeable in submerged conditions. Understanding the effects of nutrition on conidia production and quality in fungi having industrial interest is a key issue when developing large-scale production.

Key words: Complex carbon source, conidia, conidiophore, inorganic nitrogen source, medium conditions.