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Isolation and Identification of Thermophilic Fungi

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We isolated thirty thermophilic fungi with ability to grow at 45 °C on medium containing wheat bran and casein as carbon sources and produced proteases in both SSF and SmF (data not shown). The fungus strain F.2.1.4 presented the highest protease activity and was sub-jected to taxonomic characterization.
Analyses of macro and micro-morphological characteristics accommodated the isolate F.2.1.4 in the genus Myceliophthora due to the presence of spreading colonies with dense aerial mycelium and blastic conidia often borne in ampulliform swellings (Van Oorschot, 1980). Particularly, this isolate produced pulverulent pale mycelium, obovoid conida measuring 5.65-7.91 x 3.39-4.52 μm as well as conidia walls finely ornamented. Based on such …show more content…

Alkaline proteases have many applications in the industry such as laundry detergents, leather processing, brewing, food and pharmaceutical industries therefore the alkalophilic properties exhibited by proteases from Myceliophthora sp. in SSF are an important aspect to be explored.
The maximum activity for both crude enzymes was 50ºC but the crude enzyme from SSF maintained 95% of the maximum activity at 60ºC while for the protease from SmF the activity was 79% (Figure 3b). This property is consistent with the dates reported for extracellular enzymes from thermophiilic fungi. Similar results were reported for proteases from Thermoascus aurantiacus var levisporus (55oC) (Marcy et al., 1984). Proteases from thermophilic Scytalidium (Hasbay and Ögel, 2002) and from thermotolerant Aspergillus fumigatus (Santos et al., 1996) showed optima activities at 45 oC.
Since the protease activity was higher in crude enzyme solution from SSF and addi-tionally, it showed alkaline optimum pH and activity at higher temperature range (50-65 ºC), it was used for the immobilization procedure.
Entrapment of the protease in calcium alginate beads
Among the quantities of sodium alginate (2, 2.5, 3, 3.5 % (w/v)) and CaCl2 concentrations (0.04, 0.06, 0.08, 0.1 M), the best condition for immobilization of the protease was 2.5 % alginate and 0.08 mM CaCl2 (data not shown), obtaining 2 mm (average diameter) beads.
The immobilized enzyme was reevaluated

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