Morphological and enzymatic response of the thermotolerant fungus Fomes sp EUM1 in solid state fermentation under thermal stress

作者：Ordaz Hernandez Armando; Ortega Sanchez Eric; Montesinos Matias Roberto; Hernandez Martinez Ricardo; Torres Martinez Daniel; Loera Octavio^*

来源：FEMS Microbiology Letters, 2016, 363(16): fnw177.

DOI：10.1093/femsle/fnw177

• thermotolerance
• white-rot fungi
• solid state fermentation
• lignocellulolytic enzymes

Thermotolerance of the fungus Fomes sp. EUM1 was evaluated in solid state fermentation (SSF). This thermotolerant strain improved both hyphal invasiveness (38%) and length (17%) in adverse thermal conditions exceeding 30 degrees C and to a maximum of 40 degrees C. In contrast, hyphal branching decreased by 46% at 45 degrees C. The production of cellulases over corn stover increased 1.6-fold in 30 degrees C culture conditions, xylanases increased 2.8-fold at 40 degrees C, while laccase production improved 2.7-fold at 35 degrees C. Maximum production of lignocellulolytic enzymes was obtained at elevated temperatures in shorter fermentation times (8-6 days), although the proteases appeared as a thermal stress response associated with a drop in lignocellulolytic activities. Novel and multiple isoenzymes of xylanase (four bands) and cellulase (six bands) were secreted in the range of 20-150 kDa during growth in adverse temperature conditions. However, only a single laccase isoenzyme (46 kDa) was detected. This is the first report describing the advantages of a thermotolerant white-rot fungus in SSF. These results have important implications for large-scale SSF, where effects of metabolic heat are detrimental to growth and enzyme production, which are severely affected by the formation of high temperature gradients.

• 出版日期2016-8