Lipase production by some thermophilic fungi under submerged and solid-state fermentation conditions

The capacity of lipases to catalyze the hydrolysis and synthesis of lipids makes them adaptable biocatalysts that find widespread application in many different industries, including food, medicines, detergents, and biofuels. Due to their remarkable capacity to survive in extremely hot environments and to generate highly stable and active lipases, thermophilic fungi have garnered interest as potential thermostable lipase suppliers. Eighty-nine isolates belonging to fifteen species of thermophilic and thermotolerant fungi were isolated from agricultural soil at Assiut Governorate, Egypt. The identified species belonged to Acremonium, Acrophialophora, Aspergillus, Humicola, Malbranchea, Myceliophthora, Paecilomyces, Penicillium, Talaromyces, Thermoascus, and Thermomyces. All fungi were screened for lipolytic activity at 45ºC on agar medium. Results revealed that 80.9% of the tested fungi showed variable degrees of lipolytic activity. Of these, 35 isolates displayed high activity, 24 showed moderate activity, and 13 exhibited low activity. The most active isolates were cultivated in sucrose-free Czapek`s broth supplemented with 1.0 % Tween 80 at 45ºC under submerged fermentation conditions (SmF), where lipase activities varied between 6.1 and 8.33 U/mL. Utilizing solid-state fermentation (SSF) conditions, lipase was produced from olive oil processing paste using twenty isolates of thermophilic fungi that demonstrated high lipase activity. The lipase activity ranged from 8.3 to 20.8 U/gds. The most potent strain was identified as Thermomyces lanuginosus based on sequencing results of the internal transcribed spacer region (ITS).